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View Full Version : 8 ratios from an M46??


verdigo
10-25-2010, 01:23 PM
Just wondering if anyone had ever disconnected and bridged the plug for the forth gear switch on an M46 trans and tried split shifting using the over drive button for each gear?

Dennis

v8volvo
10-28-2010, 12:04 AM
It can be done, but the results are not worth the effort for a bunch of reasons. I've tried it and wished I hadn't. For one thing, the way the M46 is geared, any one gear plus OD is pretty close to the next gear without... in other words, running in 3rd+OD is almost the same as running in 4th direct. For another thing, the OD unit is not strong enough to stand up to full power in the lower gears. When I tried it in my modified 760, running in 3+OD at full power while pulling out on a 2-lane road to pass another car, when the boost came up the OD started to slip and shudder. Not a nice feeling. If your OD were in perfect conditon with perfect cone clutch, fresh fluid and cleaned screen, etc, it might hold 3rd, but probably not second and definitely not first.

Most of all, though, cutting the 4th gear switch out of the circuit means that not only can the OD be engaged in any gear, it will not automatically DIS-engage when you shift out of 4th. This means you will forget to disengage it and damage it. You might think you'll pay close attention and won't forget, but you will. I thought that, and I did. This can lead to two problems. One, the OD runs off hydraulic pressure, which there isn't any of when the tranny is stopped. So if you leave the OD connected accidentally and come to a stop sign, then start off again in 1st, the OD will slip and eventually engage, but it will be very hard on the internals. Two, you cannot back up with the OD engaged or it kills it very quickly... so if you forget to take it out then stick it in reverse to park the car, your trans will be in trouble.

verdigo
10-29-2010, 02:13 PM
Glad I asked:)

Volvoist
12-21-2010, 09:53 AM
My 242 gasser had the contact switch in the tranny bypassed when I got it in 2003. It would work in any gear, but yes, it did shudder on occasion, and no, it was not a good feeling. I have since replace the relay and the contact switch and the OD unit is sluggish. In hot weather it shudders into OD. Needless to say, it is now worn out. Was it because of being bypassed or was it due to age and milage or past abuse? I'll never know. I will rebuild it when I do the clutch in the spring or summer. I suspect the internal clutch pack is worn out.