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How strong are the overdrive units on M46's?

Wren

Wren

Porkchop Sandwiches
Joined
Jun 29, 2006
Location
Athens, GA
I'm curious about how strong the O/D's on the M46 transmissions are. Does anyone have experience with these in say, 200+ hp applications?

How much torque will they stand and stiil last?
 
I have and the answer is that they will last as long as you use the clutch to engage the overdrive. Due to the design they will hold very firm if used properly but are in no way a performance item.
 
I was interested in paring a m46 overdrive unit with a auto transmission in a non-Volvo application. Have you ever heard of anyone ever doing this? I've seen refferenced to a Borg-Warner R-10 and R-11 overdrive units. Is the M46 using an R-10 by chance?
 
The Volvo boxes got the Laycock J-Type and P-Type overdrives.
The P-Type is much stronger then the J-type.
A number of overdrives are available in the aftermarket that will require MUCH LESS cobbling then would be needed to fit the overdrives used in the Volvos.

In your Non-Volvo application you may wish to just get the flavor of four, five or six speed automatic that was offered by the manufacturer of the engine.
 
Not sure what the M46 uses, or i have never referred to it as an R10?...we got the J and P type behind the OHC M46 cars. Got the L, D and J type on OHV M41 cars I believe.
It probably won't live very long at all behind an auto unless you are coasting very gently every time you click it on/off. How would you plan on sealing the front of the OD casing and setting it up to engage the splines on its input yoke?
If you must use one of those horrible leaky overcomplicated british things that have been made obselete by a simple gear, use a P-type from an 86+ M46. Those can take a good deal more abuse and you aren't guaranteed to granade it if you don't use the clutch or coast very gently with an auto while engaging it.
 
This project wouldn't be very practical, but I was just curious about the strength of those overdrive units.
 
Mine is messing up all the time. I don't imagine it was designed for the power of the engine (but then again, I can't vouch for the various POs treatment of the OD unit)

Eamon
 
The P-Type I had behind an M-46 with a Quaife close ratio gearset did well with over 500lb/ft of torque. The P-Type is strongest of them. I did not ask it to shift into overdrive under power (often).
 
JohnLane said:
The P-Type I had behind an M-46 with a Quaife close ratio gearset did well with over 500lb/ft of torque. The P-Type is strongest of them. I did not ask it to shift into overdrive under power (often).
Click to expand...

Exactly. If people learned how to engage the overdrive they would also learn that they last much longer that way.
 
just wait till its fully engaged before you put your foot back in it.. the pump runs off the output shaft and is speed dependant soo the faster you go the stronger the clutches inside the overdrive will hold. I in no way recomend that you us it under racing but i have powered my car fairly hard "22psi or so" with the overdrive engaged but they are still weak...

Sam
 
My '83 wagon's 220,000 mile OD still works great and that's with 20,000+ miles of very high boost and abuse. I even used to use it to split gears between the 2-3 shift at the strip when the car was NA.
 
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