M46 proper engage/disengage of OD!
 

Ok this is my first Volvo as you may know and my first experience driving a car with a elec OD. When I shift into OD should I be pushing in the clutch like a standard 5th gear, shift while letting off the gas pedal, or just keep accelerating and let it shift. Now on down shifting has me baffled. Should I be clicking OD off before down shifting at all? While on the freeway today I was in OD and hit traffic, I slowed down enough to grab third and while not realizing that OD had not dis-engaged because I had to pay attention to the vehicles in front of me. I had to hit the button again and then it dis engaged. Am I just over thinking this or is there a proper in/out procedure for OD. Thanks.....

There's a knack to it...
 

I'm no authority on this but the following is how I drive the OD and it seems happy enough!

You shouldn't depress the clutch when selecting or de-selecting the OD, it has its own 'clutch' internally.

The main gearbox should have a switch that only allows the OD to be selected in 4th gear and automatically de-selects it if you move the gear lever out of that gear. (700/900 only???)

When selecting or de-selecting the OD, momentarily lift the throttle to the point where the engine is no longer accelerating or braking so that there is minimum strain on the drivetrain whilst the OD engages/dis-engages. Then re-apply throttle or release completely depending on whether you desire acceleration or engine braking.

The throttle action you want is pretty much identical to that which you would perform changing between gears in the main box, except there is a short delay between pressing the button and when you need to lift your right foot.

I find this delay depends on road speed. At 30mph it can be nearly 1.5 seconds. When thrashing flat out at 70mph the whole sequence from pressing the button to getting back on the throttle takes less than half a second.

At low road speeds (below 40 mph say) with the engine braking, I feel that the forces involved are low enough to not touch the throttle at all when de-selecting the OD. It just gently disengages, the revs rise a bit and you get some more engine braking.

Once you get the hang of where to put the throttle when, you can get the changes so smooth your passengers won't even know they've happened.

Have you ever tried changing up and down a manual box without using the clutch? If so, you'll know what I mean by 'matching' the revs. This is what you want to be doing to give your OD an easy life...

Although the 4th gear switch will dis-engage the OD when you shift down, I don't usually rely on this as, on my box, going straight for 3rd from 4th + OD catches the synchromesh on 3rd out, eliciting a fairly good crunch! If I know I'm gonna want 3rd next (approaching roundabout/traffic etc.) I de-select the OD a couple of seconds before changing down.

All this said, I get the impression that this OD is a pretty sturdy beast and will stand up to a fair amount of abuse. I occasionally have brain fade and press the button at silly times or forget to lift off the gas and it seems to survive!

Now I've got used to it, I really love my OD - its really satisfying when you get it just right...

HELLO- I have 2 1984 D24 powered wagons. One shifts more smoothly than the other (probably an age and wear factor).
Frankly, I prefer using the clutch when going from 4th to OD as if I were shifting a 5-speed w/o overdrive. It is guaranteed smooth and insures a good clean shift, especially if timed correctly.
My OD kinda 'klanked' in on the first wagon purchased. I thus resorted to using the clutch to completely eliminate that issue. Again, there may be some age and wear factors here at 300k! The OD unit may be a bit sluggish due to this. The uni-joints, intermediate bearing, and differential may also be a bit 'loose' and on the worn side.

The second wagon shifts much smoother overall. I have not tried to go from 4th to OD "straight with the button only" to see if it is better than the other one. Bottom line for me is to use the clutch. I'm quite happy with that.
I will be driving this vehicle tomorrow and will post if it is silky smooth or no.

Downshifting is usually with the clutch as well since it enables me to go directly into the lower gear of choice. Going from 4th w/OD into neutral and back to 4th puts you in 4th of course. Same is achieved by merely pressing the button. I use the clutch because many times I want out of OD and want maybe 3rd or even 2nd on the exit ramp (after braking and a bit of a coast). If the light turns green before I reach it my momentum and 2nd gear are usually the ticket.

I lean towards 'kid glove' treatment of my vintage wagons so I can continue to enjoy a great ride and 36 mpg on my daily commute between Tacoma and Seattle.

My '87 automatic gasser shifts into OD quite smoothly going both ways but that is to be expected.

Perhaps someone with a tighter drive train will chime in and offer more thoughts.

Ah well, each to their own!

This bus has only done around 170k so the drivetrain is pretty sweet...

The OD has a a screen which should be cleaned at least once every 15 years, and it may engage better if you do that.
I'm of the opinion that it should be clutched on upshift if under load, but we might not make enough power for it to matter. Mine has survived may full throttle cycles.

Well I used the 'other' wagon today and it shifted into and out of overdrive very smoothly without 'clutching'. I did ease up on the throttle to go up from 4th to OD and it was sweet. Apparently the 'klanky' wagon's OD needs remediation. The screen seems like a good start since it engages in a delayed sense and all at once- 'klank!, I will continue to use clutch for it.

I would guess the smooth OD would be the norm on this application.

As previously mentioned, shifting out of 4th w/ OD engaged should automatically disable the OD. Conversely, the OD will normally engage only in 4th. If your xmsn does otherwise there is a problem somewhere.

I have had the OD continuously disengage on it own for a short period, but a new relay completely solved that problem.

M46 Overdrive relay, 5th gear
 

My 745 d24t has the m46 transmission as well. Today I started the car, idled for about 10-12mins then drove away slowly. I have to mention that my overdrive (5th gear) usually does not work until I drive for about 2miles/or 5-8-10minutes and then it functions normally without any issues… Absolutely no problems thereafter. (I know it from a good source that it is normal for an older m46 to engage later).Today as I was driving home with a relatively cold engine and I was waiting for the tranny to `warm up`. As always, after a couple of minutes of driving I tried to switch into 5th but it did not happen. I tried again a few times and the system warmed up by then so it engaged nicely as it always does. Then I drove another few miles with no isssues at all, like everything was normal and THEN I had to slow down because of traffic and I switched back to 4th and then to 3rd (traffic). This time I saw something I never experienced before in this car: the 5th gear`s green light was ON and the tranny was in 2nd or 3rd I think. Not sure though. ...I said: how? And then took it out (pushed the overdrive button on the knob and continued driving but when the next time I needed the 5th gear again, it did not work anymore. As I was trying and trying, I even heard a click coming out from the dash (as I pushed the button). Also, it clicked by itself but 5th gear never came back to life. I heard that click (or tick), click, every 2-3 seconds for like half a minute and then never again. Do you have an opinion about this thing? I think my overdrive relay went to heaven. I did not have the time and patience to do major research at 11pm but I did check the fuse (#12) and it was alright. I don`t think that my knob is malfunctioning btw. The wires inside are in ok condition and the knob is not loose so the connection is good.
Things to know about my m46 OD: 1, it always needs some time to work but then it works perfectly. 2,if the gear shift (=the stick)is pushed to the left when car was in 4th, OD disengaged by itself (sometimes IF passenger or vibration pushed the shifter a bit towards the left) 3,My OD green dash light (5) never came up in gears other than 5th but today it did once, I believe. 4, I never noticed this click-by-click sound before, coming from the dash, middle area, maybe. Like my od relay was on-off-on-off a number of times but my od green light never came on again and I had to drive home in 4th gear (40mph @ ~2000rpm)
I do clutch when using my OD, up and down too. I was suggested to do so but on the other diesel m46 Volvos I had I never did and they were all fine for long long years. Now I do clutch when switching in and out of 5th. I don`t think an OD relay would cost more than 50-60bucks but I might be wrong.(The click click noise is gone, disappeared but still no 5th gear...)I am not sure if the relay can be/should be heard when driver switches into /out of 5th gear. I remember that in my d24 240 it was possible to put the car into 4th and then press the OD button and the green 5 would come on immediately even if the engine was NOT running. I can`t do this with my d24t 745, just curiosity...is that normal that when I put the 745 m46 into 4th and then switch 5th, with engine off, the 5th dash light would NOT come up. ?? Just wondering...

I would say there are a number of things you need to check...

The delay in operation when cold would suggest to me that a fluid and filter change would be a good idea.

If the select button is sound, as you suggest, the relay may be at fault but 'in the 4th gear switch' on the main gearbox also needs to be checked.

My 740 will show green 5 and both the relay and the solenoid on the OD will click in and out with just the ignition on (i.e. motor not running) so long as the stick is in the 4th gear position.

You need to methodically work through the suspects testing each one, starting with the electricals.

One way to check if the 4th gear switch on the main box is duff is to have the ignition on, keep the OD button pressed and then move the stick into 4th and waggle it around some. If the green light/OD solenoid flicker in and out as you waggle, the 4th gear switch will need replacing.

If you can't get any green light/OD solenoid activity at all then the relay or wiring/fuse/earthing is likely the problem. Poor contact where the relays plug into the fusebox is a common problem on older cars and it is self exacerbating. A poor contact presents high resistance to the circuit causing excessive heating of the contact. This heating increases the resistance due to tarnishing/distortion and so on until eventually the contact burns out. It would be worth checking the seating and condition of the contacts on the OD relay in the fusebox.

This circuit should be reasonably easy to diagnose logically with a multimeter or test lamp...

Tranny fluid in m46+ OD issues
 

Thanks for your ideas on fixing my OD. You are absolutely right about the relay-fusebox connection. I inspected the relays and many of them were not tight at all. Huge amount of dust as well. The od relay is out by now, it will be checked very soon and if not bad, I will move on to changing the fluid and inspecting all wiring I can reach around that area and also the shifter/knob itself. The delayed operation in my m46 was always present but no issues related to that at all, I think. I`ll see how it goes after spending some time with it.
Hey professional d24t owners, what is the best/suggested type of transmission fluid for an m46 tranny?

OVERDRIVE RELAY to be tested
 

I forgot to include my other question. How would you test if the overdrive relay is functioning or not?

M46 overdrive issues ... 4th gear contact switch
 

Can someone confirm please if this is the correct od switch for my 1985 d24t.
Thanks. The 1985 d24 is not listed in the vehicle fitment guide but I guess all m46 trannies used the same switch. Thanks.
http://www.ipdusa.com/products/7426/...contact-switch

M46 overdrive bad wires / under shifter boot!
 

After I resoldered my OD relay a few days ago, I decided to check on the passenger side seat heater switch as well. I took it apart and found out that it was completely oxidized to the point that the movement of the small parts inside was impossible. The small lightbulb that`s inside is burnt out and melted but somehow the seatheater works now. Anyways, as I was messing around at the handbrake/seatheater /shifter area removing all those plastic parts and switches, I inspected the OD`s wires that come from underneath the relays/fusebox , through the rubber shifter boot and up all the way to the 5th gear button on top of the shifter. I noticed that the connection near the fusebox was loose and both wires were so much hardened that I couldn`t even bend them. They cracked when I touched it (inside the rubber boot). Days ago I was about to order a 4th gear switch and a relay as well from ipd but today my od problem seems to be solved finally! I removed the aged heat shrink cover with the old plugs along with the cracked-burned wires. I used new wires and plugs to make sure they will not ground anywhere again causing me fake tranny problems. : ) Lesson learned. If you have m46 od issues, peel the shifter completely of all parts and inspect ALL wiring before you start worrying condemning your OD. I tested the od and it worked fine! ((At least I checked the fluid levels and learned a lot again about the M46 manual transmission (4-speed + Laycock de Normanville overdrive))). The green dash light came up happily so I finished the job with installing all dash covers and parts of shifter back. What a pain to get all that wiring into the tight shifter! I realized only later that the shifter knob was pushed down too much so it wasn`t easy to put the car into reverse. I also got surprised how much of greasy dust had accumulated on the shifter at the base where it moves down there… I had to remove lots of dust/hair/sand mixed with old grease to free the junction for some fresh synthetic ball-bearing grease. Oh, what a difference it makes! Now the shifter moves freely, goes into 1st and 2nd much lighter and reverse is easier too. Proper lubrication and the freedom of moving for all the shifter`s parts. I would love to get a new spring for the shifter btw (for the reverse) so it would be more comfortable to not to have to push that black thing down after getting out of reverse. All Volvos I drove had that thing `jump` down immediately but mine doesn`t. They even have that typical click sound to it. I also could not figure out how to get to that spring for removal but that`s not a big thing now. I will also buy a new 5th gear button so the `5` will be visible on the shifter. That would help me out explaining the tranny for curious observers and unbelieving passengers. :) Thank you for your attention and all previous suggestions on fixing my m46 od issue!Attachment 51

Attachment 52

Attachment 53

Attachment 54

Attachment 55

Glad you got your OD problem sorted out...

For reference, there is a complete wiring diagram for the overdrive circuit, including the relay internals and pinout here: http://forums.turbobricks.com/showthread.php?t=202693.

I'm certainly going to save the drawings at the end of the post for any future diagnosing I may have to do...

Boots.

overdrive wiring
 

Wow, that`s really a great source! I saved them for later! Now I just have to learn how to use them :) Isn`t it easier to understand Egyptian hieroglyphs in Gizah (at night)? :( That last wiring diagram drawing scares me more than a triple flat tire at 90mph.

It's just what you get used to I suppose. (I'm an electronics engineer by trade so I have to read schematics like these all the time!) The last diagram is actually of the circuit internal to the relay itself and is a very belt and braces design to ensure that the OD doesn't drop in or out due to electrical noise from the car's other equipment. In a 'cleaner' electrical environment, you could do the same job with about 5 components rather than the 20 odd shown there.

What's nice about the earlier diagrams is that they show ALL of the connections, their locations on the vehicle and which legs of the circuit carry current under which conditions - very handy...

Summary of the relay operation is as follows - for anyone needing to test one:

Pin 15 - +12v from ignition switch via fuse.

Pin 31 - Permanent circuit ground. (Chassis).

Pin 85 - 4th gear switch connection (enable). Relay will only engage if this pin is connected to chassis(grounded). (If relay is engaged and this pin is disconnected from chassis, relay will disengage.)

Pin 86 - Trigger input. Applying 12v to this pin momentarily (normally done using the pushbutton switch on the gear lever) will engage or disengage the relay sequentially for each application of the 12v signal. (If pin 85 is grounded.)

Pin 87 - Output of relay. Supplies 12v when relay is engaged. In normal use, supplies the current to light the bulb in the '5' light on dash and to engage the solenoid on the OD.

Interestingly, all of this is only needed to allow the use of a push-button rather than an on-off type switch to select or de-select overdrive.

If a slide switch or similar were used, none of the fancy circuitry, or even a relay would be necessary! It would just supply current to the lamp and OD solenoid in the 'on' position and not when 'off'.

Boots.

I had to do this also.

Symptom: Could not engage OD. No response from pressing OD button driving in 4th gear.

Removed switch button, cleaned contacts, continuity testing showed better switch operation but still no OD. BTW, can test circuitry (engine off) via key in run position (disconnect GP relay ground terminal wire to avoid burning out the GPs), gear selector in 4th. Pressing the OD button should light the green indicator in the instrument panel, and should provide audible solenoid click.

Could get intermittent OD operation by pushing or squeezing the red OD relay on the relay/fuse panel.

Removing the cover of the OD relay (the hardest part of this process), and inspecting with a high-power loupe showed that ALL the soldered connections at circuit board-to-base were suspect. Minute cracking. I could get one to test intermittent continuity when flexing the two pieces.

This is the area on the other side shown in Redarrow's photo, sorry, I didn't get any photos of this.

Resoldered these joints with a 40-watt soldering pencil w/ sharp fine tip, and fine (.032" dia.) solder. Regular soldering gun and normal dia. solder would have been impossible here.

Driveway test showed consistent OD operation. Test drive today.

OD disengages itself while driving
 

Issues with the m46, I believe, became known as `typical Volvo problems` that are very familiar among all those who ever had one. Interesting that my OD started living its own life again, also making decisions by itself... Issue: When I drive through rough surfaces that shake the car, or, when I hit a pothole/larger bump; then the 5th gear disengages by itself and I have to press the button on shifter to get back to normal (5th)... And it always takes it nicely and smooth & goes back to 5th the way it should. This frustrating action of jumping-out-of-5th thing *never* happens on flat roads. Can this be related to a worn transmission mount at all? I know that my tranny mount has been replaced not too long ago by someone very reliable. So now I`m wondering what causes this uncomfortable `in-and-out` thing.
(Btw, I want to mention here that it does not put itself *back* to 5th... only simply gets out of 5th by itself, at those mentioned circumstances).
Is there an easy way to remove 4th gear switch from transmission for inspection when the car is lifted? (As far as I remember there`s no great access to that without removing the tranny but I might be wrong about that.) I actually hate this thing to happen at or above 60mph.
Oh please, also, write suggestions on what`s the proper (highly suggested) type of tranny fluid to be used in the manual m46 transmissions. Thx!

Test for 4th gear switch is to hold shift lever hard down and to the right. That is supposed to make better switch contact. If that doesn't help on a bumpy road, than I would look again at the OD relay. I had to use a loupe and strong light on mine to see the cold solder joints at the junction of circuit board to base. Only then was it very obvious. Textbook cold solder joints. I had similar problem where if I could get OD it would switch itself off, often over bumps.

Type F ATF recommended for M46. There is a filter(s?) in there to clean.

Got my trans back!!
 

I just got my trans back this afternoon. Should be good to go for another few hundred thousand miles. I also modified the shifter for a little shorter throw and installed a stud so that I can put a threaded shift knob on. I will be moving my O/D button to an open spot on the dash.

Here is the link below. I cannot figure out how to imbed the picture.
https://www.dropbox.com/s/3vdc4r3eom...2018.26.29.jpg

https://www.dropbox.com/s/3vdc4r3eom...2018.26.29.jpg

Small spring on m46 shifter
 

That transmission looks nice&fresh. How much is a complete overhaul?
BTW Did you think about having the original `5` built into your dash? (next to the rear demist switch maybe if there`s room still) :)

Also, another thing... last time I took mine apart I was wondering how to remove/replace that spring on the shifter that`s serving the black ring`s vertical movement for position `Reverse` of the shifter. It was too late+dark to figure it out. Anyone did that spring replacement? I could not find a place to order the spring from either.

It`s good to know that www.ipdusa.com sells great m46 parts and service kits if anyone interested.
http://www.ipdusa.com/newsletters/10...ter-components

I am lucky enough that my dad has been rebuilding Transmissions for 40+ years and owns his own Transmission shop. So I only have to pay for parts. I did find out that volvo parts are either
A.a SOB to find
B.priced at stupid high prices
C.most likely hard to find at even stupider higher prices. (Yes I said stupider)
I am only into the whole trans and O/D rebuild $300. That includes a dumb $130 bearing in the O/D that I probably didn't need but I bought out of self insurance that the trans wont go out for a long time!!!!

The shifter mods are totally free since I had everything laying around. I will be using a different shift knob. I think I will be putting the O/D switch down near the E-brake handle since I have 2 open spots and down there.

What is a demist switch?
What is an original 5?

Demist switch is also called rear window defroster? "Original 5" I think means the green "5" that lights up in the instrument panel when OD is energized.

13-20
 

Here we go again,
with the same fluid-question `popping up` ...

more than 7 years later,

and the same m46 still running okay and very reliable. :cool:

Today I lifted the car up to check the undercarriage and inspected wirings of the m46, also to attempt opening the tranny drain plug and fill plug (Murphy never sleeps so I did that in the exact opposite order ;) )
Despite some nightmare-ish stuck drainplug stories, in my case loosening both of them went really well... though I used a gas torch and a hammer to help break up the very tight, corroded connection (not because of an existing rounded plug issue but to prevent any bigger issues).


The tranny fluid that leaked out looked really dark.

I checked the original greenbook manual and I got surprised by what I read: for the m46 it suggests the 600-1000km ATF replacement (after first miles when car is `new`) then none(!), except topping up fluid If missing (This seems weird BTW--how often do You change your m46 fluid? In miles, or in years, share with me whatever you do with your m46)

Also, is it true that the required amount for the m46 is 2.3-2.4 Quarts (2.4x947ml)? What exact brand and what exact F type atf to use?

I found this, part of a full rebuild instruction sheet for the m46, written by IPD Volvo specialists:
``The M40 takes .8 qts of 30 wt, the M41 uses 1.7 qts of 30 wt, the M45 uses .8 qts of Type F automatic trans fluid, the M46 uses 2.4 qts of Type F and the M47 uses 1.6 quarts of Type F.``

The d24t m46 manual suggests that the correct level is right at the lower lip of the filler plug so I guess, if the correct fluid level is the filler plug itself then we can not overfill the m46 tranny even if we wanted to (car obviously should be level for this service).
Is it suggested to slightly overfill it though, as you might do the engine oil by adding 1/4 quart extra for a worn out and/or cold-climate diesel brick? I welcome your experience and happy to hear your own m46 story and m46 atf habits.

I haven`t changed the fluid in any of our m46 Volvos (never had a single issue with any of our m45 or m46 trannies, for tens of years, ever)...

so can someone verify a few m46 details please? Thanks.

Also, IPD suggests that in case of a worn (or misbehaving) manual brick tranny we could/should use 10 W 30 synthetic motor oil (Castrol etc). Anyone tried that?
I have no issues but sometimes the motor oil is much easier to find on the shelves than finding an F type ATF. Especially at /\utozone (plus there`s the covid factor, reduced staff, lines, no customer service etc).

IPD says:

``M46 & M47 Transmission Oil
Created on 2011-07-29 by IPD Staff
From the factory, automatic transmission fluid is the specified fluid for both the M46 and M47 transmissions found in the 200/700/900 models. Over the years as synchronizer rings wear and tolerances increase, we have found that changing the transmission fluid to synthetic 10W30 motor oil makes a noticeable increase in smoothness and gear engagement. We have even noticed ‘weak’ overdrive engagement has become firmer with the new fluid. Using your clutch when shifting into overdrive can also help to reduce wear on the overdrive.``


Diesel brickers, could you let me know your best advice about the most proper fluid for my m46 transmission diesel car?

Because my m46 atf fluid level seems lower than the suggested amount, i want to get this done tomorrow and test the car right after for increased smoothness (sometimes, very rarely though, I feel the shifter not liking the 1st gear at redlights and going into reverse isnt 100percent smooth either, sometimes audible)

I appreciate good ideas, thanks for reading this long m46 thing.

OMG one more question,
According to the manual and a previous comment too, there is a `filter` or `screen` that must be flushed/cleaned/declogged. The overdrive unit must be holding some fluid too, I am sure it should be drained too by removing this cover.
Where is a filter located? I saw a nice easy-access, flat cover right under the overdrive unit, held by 6 bolts. I assume that is the filter /screen that is serving the unit.
Is there another filter anywhere in this m46 unit?

also, can I get away reusing the overdrive bottom gasket, do you think is it doable that way? Is that gasket still available somewhere? (update: yes, found it)

Hoping to get this done early morning tomorrow, possibly get the Mobile1 TD synthetic engine oil in, too. I know this car really appreciates that.
THANKS FOR THE M46 ADVICE!

Yes, a cup-shaped coarse wiremesh filter under the largest round screwcap cover visible when you remove the OD rectangular finned oil pan and the main filter.

I've never seen either of these filters dirty or clogged. They are too open to trap much, unless there was catastrophic damage that caused larger chunks to break off and circulate. Usually the magnetic drain bolt is covered in fine metal paste.


The OD oil pan gasket is usually in good shape, but YMMV, and remember your Murphy's Law. Get a spare, and you won't need it. ;)

Overdrive type 5th gear manual transmission m46 fluid change. Needs ATF `F` type
 

Ngoma, thank you for your response, though unfortunately I only saw your message after I finished this project.

I probably need to go back in there and do it again because up until I started the fluid change I thought there was only one filter
and didn`t really look around for another one.
This is proof that I never changed fluid in an m46.

Could you explain where exactly a 2nd filter is? (I can see a scratch mark on the largest round thing that I did not do) I am guessing you access that filter under there.
Update: I found info online, yes there is a damn 2nd filter in there.
Brickers, read info here (if it is not OK to link in another volvo website on this forum then OP please delete this part as you wish):
https://www.brickboard.com/RWD/volvo...rs_prices.html
Here`s another link directly to the filter (to see how it looks):
https://classic-volvo.com/140-142-14...-type-j-p.html

In my case, that 2nd filter ALSO might be clogged or at least covered with some fine metal paste.
In this m46 today the larger square/rectangular screen/strainer on the bottom of the overdrive pan was buried in very fine metal paste, grey in color. Not just a little bit, it was truly covered. Also the magnetic drainplug was pretty much covered in fine paste.
Using half a bottle of brake cleaner, gently but directly, worked very well on the strainer, and it got pretty clean. No big chunks of metal, no larger visible dirt particles found, luckily. The bottom of the `pan` (the inside of the overdrive cover) was fully coated too with the same grey metal `cream` also the large bottom magnet too, and the inside of the `tube` that leads into the wire cage screen.

It all cleaned up really nicely and there was no damage, also, you are right Ngoma, the cover gasket was in good enough shape to be safely reused and there are no leaks anywhere whatsoever.
I rechecked it twice after testdrives.
The drain and filler plugs both have now a new copper washer on them and tightened using common sense (i didnt have the greenbook with me this time).
Maybe when I flush this new fluid out again in a few miles down the road, maybe 50 or so.
Then, I will make sure to take out and clean the 2nd filter that I missed today.

The old fluid that came out looked really dark but not murky,milky not full of metal parts; but oh boy it stank! Imagine a rotting marsh area in record Summer heat OR this: by true memories of his safari expeditions, my helper bricker-buddy said, `disgusting elephant poop, full of rotting grass` .
AT THAT POINT HIS SOCIAL DISTANCING SKILL IMPROVED BY 100%, TO 12FT.

About the fluid amount.

I captured it all but lost some at the lowering of that overdrive cover.
I then contained it all in a 1-liter Seltzer bottle that didn`t even get nearly full!

2.4 quarts is the fluid capacity of the m46 unit.

The required 2.4 QT equals with 2.27 liters (=more than 2 full bottles of that same Seltzer bottle, 2.27 bottles to be exact).
I only captured about 850milliliters at the maximum, which is about 0.85liter. Definitely not 2.27liters (2.4 quarts). The 0.85liter equals about 0.9 quarts. ONLY*

That is not even close to 2.4 quarts! I did not lose too much fluid on the ground but some of the old fluid may have remained `trapped` inside the m46.
Still... i didnt like the facts.

Then, 2 quarts made it in, not a drop more.
Yes, the car war warmed up, not just the engine, I drove the car 10miles on local roads so the tranny fluid was warmed up to be drained properly. Yes, the car was completely level and I did check it twice. I even took a 6t jack to slightly lift the left side about 1cm higher than the right.

I didn`t want to end up adding less fluid than what it could take, also if it wasnt parked on a totally flat surface it would take less (if a car/road tilted to the left)

So, 0.9 qt came out, 2qts went in.
This is with the overdrive cover also removed and all old ATF drained.
I`m a little confused about this because I don`t see leaks anywhere and luckily the area And the bottom of my car is very dry.

If someone told me that this was the very original m46 fluid from the factory and never been opened since 35years ago, I would certainly believe him.
(Except that I expected old fluid to be much thicker and totally `worn` but surprisingly it was still pretty much `liquid` :) ).

The tranny now shifts much better although I did not have any shifting issues earlier. Never abused the car and it never gave bad sounds, was not throwing itself out of gears etc.
But, now, it feels so much more right!!
I got back the original Volvo feel from when I drove these cars in the 90`s. The result is most noticable in reverse, first and second gears; but the overall feel improved a Lot, as well. And in and out of 5th is more responsive and smoother. As I said, it just feels so much more right.
What a great day, the tranny feels so much happier. And my mistake will result in a tranny flush for her. :)

I will go back in 50miles and use new ATF again, one more time, and get that 2nd filter cleaned. Any experience with the o-ring that is in there? Does it ususally look bad? Reusable? Maybe I should have it but these days ordering something is pain. It takes weeks to get parts. Plus hey it cant be 50bucks, damn?!

I`ll add pictures for those who did what i did: never change(d) fluid in the manual tranny for so long.
For me, it was worth changing it (great results).
BTW The cost was 2x5.99=$11.98 +a bottle of brake cleaner spray ($2.50) + (5.99 for a spare 3rd bottle of ATF)

The leftover bottle of ATF was used for topping up the power steering reservoir and tomorrow I can fill the rest into a new fuel filter. If I still have some left of the 3bottles after all of that, I`ll add it to the main fuel tank (diesel car*). :) Not bad! :)

You sure did a good job cleaning that all up. It may have been underfilled for quite a while.

Wrong ATF for the PS. The PS system wants common Dexron, not Type F, not Power Steering Fluid, etc.

Why not use the extra Type F to overfill the trans. like you were starting to do? Jack up the left side, fill until it comes out of the fill hole. They work better overfilled that way.

Be interesting to see what settles out of your old captured fluid.

Overfilling of the m46 by how much???
 

Oh shoot, true. The PS does not use the F type. Right!!
IDK what hit me when I topped it up using the F type (though it was only 1/2 inch lower than the `HOT FULL` mark so I didnt add much but still (it was warm, after the test drive) but I don`t understand myself, I even have the proper MercIII bottle right there in front of the battery tray, UGH.
I`ll just empty that ``PS`` reservoir :D and use the other atf in it.
At least the steering gets a flush too (plus it will have the right fluid).
THX for the note.

About the tranny.

I did not know that it does do good for the m46 to be overfilled.
I thought of it and I did make sure the left side was a little higher but by not much. I was hoping the m46 would take 2.5-2.6 qts instead of the greenbook 2.4... but it still only took 2quarts.

If I decide to overfill it purposely the next time,
What do you think is the suggested amount of overfill as expressed by quarts? Entire m46 takes 2.4 they say but it only took 2quarts.
Would you fill it using 2.5 or 2.75 or 3 full quarts? 3 qts would be a 25% overfill approximately. :eek: compared to the factory 2.4 suggestion (of which it only took 2. So if 3 used, there would be a full extra qt in it above the 2 that normally filled the tranny with car being level.

Many owners actually do that? Is it necessary? In this m46 everything has worked fine so far so I maybe simply lucked out that I had no issues with level being that low (good that this car has no abuse except some occasional Italian tune-up; with hot engine).

I don`t think this tranny fluid had been changed since at least ten years ago. Probably much more!
Okay I`ll flush out this atf from the tranny in 50miles and report back about what came out.
By then I should also be able to find that inner o-ring next to the secondary fine filter.

Is it a good idea to remove and clean another part while `inside` the m46?
I guess when something works fine we could leave it alone... but there may be another part to look after too.

Learned from the longtime Volvo heads over at turbobricks.com who have run the m46 a lot more years than we have.

Your computations are confusing me. The idea is to jack up the side of the car and fill the trans.

I meant the old oil you collected in the bottle.

It's not a FINE filter, it's a COARSE open weave filter. Doubt you'll find much of anything in that filter.

Can't think of anything.

Yep. Best wisdom I've heard all day.

Don't make problems for yourself. ;)

ATF mismatch
 

Thanks for your reply.
Yesterday I drove the car to Autozone and bought 3bottles of the F type ATF again, for the next tranny fluid job where I`ll try to slightly overfill the m46 as you suggested, maybe by 0.5qt max (100-500miles from now). No leaks noticed anywhere on the tranny yet, so that`s good news. Shifting feels so right, loving it!

I also bought another bottle of the Merc3-5/Dexron type ATF. Yesterday I also sucked out the F type ATF that I wrongly used earlier as `power steering fluid`... and finally the steering reservoir was filled up with the correct version of ATF fluid.
Thanks again for the note.

Does anyone happen to have an m46 laying around? Would be nice to know the measurements of the two holes under the round inside filter of the overdrive unit. I`d make the tool in advance to make the fluid swap as quick as possible. Not much torque on that barrel shape thing, according to the m46 greenbook manual that I have. So I might be okay with just any diy random tool or even with some beefy circlip pliers. I thought of making this tool to access the filter... I`d be using cut-out socket so that`s why the measurements of the holes would be great, center to center and the hole diamater. In this case my own socket would let me apply the proper factory torque value by using the socket-tool (after flushing the filter). Thanks!
I have a vw timing tool that actually looks like it could be the right fit but my tranny is filled now and I dont feel like doing the job just to measure things. If anyone has a dry m46 around, that`d be great. It is a J type btw.