Allison differences b/w 2 and 4wd?

[I Love Grits]

So what, if any, are the differences between the 2wd and 4wd Allison transmissions? Is the output shaft housing the only difference between the two, thats the only thing i could think of.

Thanks in advance.

[I Love Grits]

Nevermind, figured out it is just the ouput housing.

[More Power]

So, you just need to swap output housings, and the driveshaft slip yoke will fit the trans output shaft?

Would be good to know that - just in case.... :)

Thanks,

Jim

[77TransAm]

Everything behind the P3 carrier is different - different output shaft, retainer, yoke, housing, seal, etc. I think I covered this in some depth back in '01 or '02 when I used to post here a lot.

It's not a difficult conversion, though; we used to do it all the time when we would swap units between test trucks. If you had both a 2wd and a 4wd unit, you could unbolt the rear covers, pick them up (all of the requisite parts would stay with the rear cover), bolt them on the other units and you would be done. It'd be a good idea to check the endplay after you swapped, but that's usually within specs.

NO, the 2wd yoke will not fit on a 4wd shaft; the 4wd shaft is smaller in diameter.