D24T.com  

Go Back   D24T.com > Technical Discussion Area > Diesel Engine and Drivetrain

Reply
 
Thread Tools Display Modes
  #1  
Old 03-15-2011, 04:11 PM
Jason's Avatar
Jason Jason is offline
Owner/admin
 
Join Date: Jun 2009
Location: St.Louis, MO
Posts: 1,266
Default Towing with D24t equiped 7xx series??

Anyone here use their car to tow, if so how heavy? The manual says 3300lbs, which I was suprised as that seems pretty heavy. I'm trying to buy a trailer hitch so I can drag my flatbed trailer around from time to time, mostly just to go get it or if I need to haul something bulky but not heavy, rather than to use my gas guzzler truck. I was also thinking about doing a trailer brake controller just to help since it does have electric brakes. Any things to look out for towing with a 7 series I should look out for? I'm not a novice when it comes to driving with a trailer by any means, but I've never used a car to tow with. I know the engine will be up to the task! It will be doing some work!

Jason
__________________


Back again with a '84 760 GLE D24T/ZF

SOLD but not forgotten! 1984
760 Sedan, built D24Tic/ T-5 swapped

My engine build: http://www.d24t.com/showthread.php?t...t=engine+build
T-5 swap: http://d24t.com/showthread.php?399-W...to-quot-w-pics!
Reply With Quote
  #2  
Old 03-15-2011, 06:57 PM
casioqv casioqv is offline
Senior Member
 
Join Date: Apr 2010
Location: California
Posts: 153
Default

This is one of my favorite subjects!

I do a lot of towing with 7 series, and think they tow really well. Although far from recommended, I've towed a ~7,000 pound trailer from Portland, OR to Seattle, WA with a D24T 760, without any issues; the factory rating of 3,300lbs is definitely doable. I towed a ~5,000lb trailer 1,000 miles when I moved from Portland to Riverside, CA and now I tow my ~3,000lb sailboat all over the place. The sailboat tows easily and effortless, but the heavier loads were due to "emergencies" and required very careful driving.

The most important thing is great fade-free brakes plus good trailer brakes. A strong hitch, rear suspension, and cooling system are a must also.

My recommended upgrades for heavy towing with a D24T:
-Healthy cooling system with audible alarms on temp and coolant level
-Strong electric fan or tropical fan clutch
-PBR Ceramic brake pads
-ATE Blue brake fluid, changed annually
-iPd overload coils and Bilstein HDs in the rear
-A class III hitch (5,000lb+ rating, 2" receiver: might be hard to find)

Upgrading to the 9xx "big brakes" is a pretty good option also and only requires the rotors and caliper bracket (you can actually keep the same calipers).

An automatic with cooling system upgrades really is better for towing, because it can be very hard/impossible to get a heavy trailer moving up a steep hill from a standstill with the manual transmission. The static forward force they're able to generate slipping the clutch in 1st @2400rpm is only a small fraction of what an automatic makes at stall speed in 1st.

I have an extra 7xx class III hitch I may be selling soon...
__________________
'84 760 D24T/M46
'86 Isuzu Trooper Turbo Diesel
'01 VW Golf TDI
Reply With Quote
  #3  
Old 03-15-2011, 07:23 PM
Aidan Aidan is offline
Member
 
Join Date: Dec 2010
Posts: 54
Default

A couple of years back my neighbour's car broke down just as they were in the middle of moving house. I went out to tow them home which is at the top of the mountain I live on. They had a 760 wagon, which was packed to the brim, plus an 8x4 trailer loaded to the hilt, so a good deal more weight than my 740 2.0 n/a auto petrol wagon. It pulled the lot up the mountain without any effort at all, so a D24T will have no problems pulling a load. I've used the 740 on God knows how many occasions to tow car's, trailer's, caravans etc, and I cant say anything bad about a 740's towing characteristic's, it's a great towing car and has never shown any unusual driving behaviour when towing. A trailer brake is always a good idea, but I've always had flawless operation from the brake's, even doing a panic stop while towing another car, it's then that you realise just how powerfull the brake's on these cars are. Unless your trying to pull Mount Everest I dont think you'll have any worries towing with a 740. A little tip that might be usefull, as your well aware whatever your towing often blocks your reversing lights, so I fitted a rectangular fog light to the bottom edge of the tow bar and wired it into the reverse lights. The amount of light it throws out leave's people in no doubt when your reversing, being so low to the ground it wont dazzle them, and it lights up an area of maybe 20 yards so you can actually see what your doing at night on an unlit road. You can add a simple on/off switch to the curcuit to deactivate the light when your not towing if you want but I leave mine permanently activated due to the roads I drive on.
Reply With Quote
  #4  
Old 03-15-2011, 08:11 PM
Jason's Avatar
Jason Jason is offline
Owner/admin
 
Join Date: Jun 2009
Location: St.Louis, MO
Posts: 1,266
Default

I doubt I would ever tow more than 3000ish pounds, however I would rather have the class 3 hitch with some extra room to grow, rather than the just good enough class 2. I found a class 2 on turbo bricks that the guy only wants 70 bucks for, but I was planning on doing some welding and bracketing to add some strength. Where is your hitch attached to the car for it to be able to haul 7000lbs and not rip off?? Who made the class 3 hitch for the volvo?

As for the car itself, I have been looking for the big brake upgrade anyway but there are never any of the cars at the local yards around here. My car is lowered slightly so I wont be trying to push the tongue weight. If I need to tow a car or something I have a F350, but for lighter loads I thought it would be fun to put the volvo to work a little.
__________________


Back again with a '84 760 GLE D24T/ZF

SOLD but not forgotten! 1984
760 Sedan, built D24Tic/ T-5 swapped

My engine build: http://www.d24t.com/showthread.php?t...t=engine+build
T-5 swap: http://d24t.com/showthread.php?399-W...to-quot-w-pics!
Reply With Quote
  #5  
Old 03-16-2011, 02:51 AM
Aidan Aidan is offline
Member
 
Join Date: Dec 2010
Posts: 54
Default

The tow hitch frame attatches to reinforced area's under the rear wings, or fender's as you guys say. The mounting holes are already there so need to go drilling holes. On the left hand side just below the bumper you should have a "tie-down" bracket (for shipping the car when new) remove the 3 bolts that hold this in place and thats where you bolt the frame to, you'll find 3 more pre-drilled holes in the same place on the right hand side. The holes are already threaded so all you need are 3 more bolts the same size as the one's you remove to get rid of the tie-down bracket. Look in the boot (trunk) at the very rear of the right hand side and you will see a wiring loom running from right to left, thats the loom for the lights so just tap into that for your trailer lighting. Fitting a towbar on these is very easy to do, so easy you can do it single handed. There's no cutting or bending things to get the frame to fit and nothing gets in the way so you can actually do it on your own. On some models you might have a shallow "spoiler" or skirt attatched to the rear bumper held on by five 8mm bolts, if you have that on your car, you can either just cut a small hole in the center to clear the frame neck, or just throw it away, it doesn't really do much anyway. With the weight your planning to pull, you dont really need any extra reinforcing on the frame but by all means beef it up.
Reply With Quote
  #6  
Old 03-16-2011, 08:42 AM
casioqv casioqv is offline
Senior Member
 
Join Date: Apr 2010
Location: California
Posts: 153
Default

Quote:
Originally Posted by Jason View Post
I found a class 2 on turbo bricks that the guy only wants 70 bucks for, but I was planning on doing some welding and bracketing to add some strength. Where is your hitch attached to the car for it to be able to haul 7000lbs and not rip off?? Who made the class 3 hitch for the volvo?
The hitch I've towed those heavy loads with is a hand made one off unit that looks like something you'd find on a 1 ton truck that I found at the iPd garage sale. It attaches with the bolt holes that are there, but unlike some hitches uses all of them and I used very high grade bolts.

My second hitch is a mass produced one made by DrawTite, and is stamped with only a 3500lb rating, but has a 2" receiver. It looks pretty heavy duty (comparable to what you'd see on maybe a 1/2 ton truck), but doesn't really compare to the hand made one. I'm not sure if DrawTite sold these for 700s, or if it is a "universal" truck hitch that was adapted to the car, although it also uses all of the factory mount holes.
__________________
'84 760 D24T/M46
'86 Isuzu Trooper Turbo Diesel
'01 VW Golf TDI
Reply With Quote
  #7  
Old 03-16-2011, 09:07 AM
Jason's Avatar
Jason Jason is offline
Owner/admin
 
Join Date: Jun 2009
Location: St.Louis, MO
Posts: 1,266
Default

Ya I would like to have a 2" reciever, I have a bunch of 2" ball mounts around anyway. That standard class 2 reciever is pretty small.

Jason
__________________


Back again with a '84 760 GLE D24T/ZF

SOLD but not forgotten! 1984
760 Sedan, built D24Tic/ T-5 swapped

My engine build: http://www.d24t.com/showthread.php?t...t=engine+build
T-5 swap: http://d24t.com/showthread.php?399-W...to-quot-w-pics!
Reply With Quote
  #8  
Old 03-23-2011, 05:30 AM
Jason's Avatar
Jason Jason is offline
Owner/admin
 
Join Date: Jun 2009
Location: St.Louis, MO
Posts: 1,266
Default

Tyler,
do you have any pictures of your trailer hitch? I'm interested to see where its braced and what it looks like in general. I'm going to be making some improvements to the stock one I'm getting. I already orered a class IV reciever tube so I can use a standard 2" ball mount.

Jason
__________________


Back again with a '84 760 GLE D24T/ZF

SOLD but not forgotten! 1984
760 Sedan, built D24Tic/ T-5 swapped

My engine build: http://www.d24t.com/showthread.php?t...t=engine+build
T-5 swap: http://d24t.com/showthread.php?399-W...to-quot-w-pics!
Reply With Quote
  #9  
Old 03-31-2011, 08:58 PM
casioqv casioqv is offline
Senior Member
 
Join Date: Apr 2010
Location: California
Posts: 153
Default

Sorry, no pics of either hitch and my digital camera is not working right now I'm not sure if I could get good photos without removing it from the car anyway.
__________________
'84 760 D24T/M46
'86 Isuzu Trooper Turbo Diesel
'01 VW Golf TDI
Reply With Quote
  #10  
Old 06-11-2020, 10:18 PM
RedArrow RedArrow is offline
Senior Member
 
Join Date: Jan 2013
Location: New York
Vehicle: 1986 Volvo 745 TD
Posts: 900
Default m46 manual tranny, not m47, towing limits such as speed and weight

Nobody seems to mention here the push-button 5th gear on m46 tranny....

It is not the best tranny for towing ultraheavy near-the-limit rigs.
The greenbook or the m46 greenbook (idk which one) even mentions somewhere some speed limitations for when towing with the m46.

But my family we used to tow with the m46 cars and never really had trouble screwing the tranny. Mountain areas may result having a totally different or opposite experience.

I`m thankful if you share your experience towing with m46 with laycock overdrive. it isnt a real 5 gear tranny as they say

Pulling a heavy load (another car etc) plus weight of trailer, especially from standstill or uphill, might really be a bad day for the laycock 5th gear button setup tranny.
The write up actually suggests a max speed limit for the m46 when towing, at about 52 or 60 kph i think. KPH, not mph. I`ll try to find the article written by Volvo.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -8. The time now is 10:29 PM.


Powered by vBulletin® Version 3.8.10
Copyright ©2000 - 2024, vBulletin Solutions, Inc.