4 Speed Transmission mated with a 3 Speed Transfer
I have not personally done this swap but thought I would collect notes on it since so many people have asked about it:
The part number for the idler cluster shims used when swapping 3spd tcase
gears into a 4spd case are #36263-60010. I threw those shims in and checked with
a feeler gauge - right in the middle of the .004-.016 range!! There are other
shim sets as well - #36262-60010 and #36261-60010. They are respectively thinner
than the shims I used (not sure of the actual thickness). I think they cost me
about $4-5 a set from Toyota!
Also, make sure you use the orange bushings from the 3spd tcase, the 4 spd bushings are too thin. See the pic below, from left to right - new 3spd tcase bushing, old 3spd tcase bushing, 4spd tcase bushing! Big difference!! You also need to use the spacer between the needle bearings from the 3spd.
Other things I did, I used the output shaft from my 4spd tcase (fine spline front output) and the front extension and housing (gusseted). I used the 3spd rebuild kit from SOR, but the tcase topcover oil seal for the hi/low shifter in that kit will not fit on the 4spd tcase. All the other bearings, gaskets, seals, etc were the same.
HTH someone down the road!