Originally Posted by nevada

*this is for a dual toyota t-case set-up.*
i know the shop is a mess.... so dont say anything

OK, since i had 2 extra forward cases, i decided i HAD to make them work for my marlin crawler. i know this isnt NEW. and using a forward shift case for the RANGE box has been done. but i needed it to work for the rear 4WD case.(id heard it couldnt be done:shaking: )

im not going to go through the teardown. hopefully if you are attempting this conversion, you already know how to tear it down.
*im going to refer to the 4L-4H rail as LEFT*
*the 2WD-4H as RIGHT*
1)get the SPARE shift fork from the DONOR case. and cut the lug off, using a die grinder. be sure not to cut it too close.

2) install the rails into the RANGE portion of the rear case. after the rails are in, put the shift detents back in place. this will help insure correct placement. and carefully measure for the roll pin. its VERY important to get it right. measure 5X cut once. leave the LEFT rail in 4wd(toward the front) and shift the RIGHT rail into 4wd also.(to the front.) mark where the new hole has to be, for the LUG on the right rail. i tried to match the lug(NOT THE HOLE) to the other fork as best i could.
do NOT attempt to drill the rail. it is hardened steel, and you will never get it. even if you could, i doubt it would be straight. i took mine to a local machine shop(Machine Service inc.)

3) grab the ends u cut off, and remove the gates. set them aside, for now.

**note** this pic is out of sequence. when removing the gates, be sure to remove the entire portion off the 2WD gate. this prevents the shifter from falling into "space" when in 4L. i had to go back, and add this piece.

4) attach lug to the right rail, and the fork to the left rail, and the you need to clearance the INSIDE edge of each lug. you need a "flat" section to attach the gates to. since the lugs are angled, it wont be square. i ground them down close, and just clamped to the THICKER side. and filled in the small gap.

5) once you're certain you know where theyre going. carefully weld the gate onto the lugs. use the SHORT gate on the LEFT(with FORK) rail. and the LONG gate on the RIGHT rail. *see my note above.*

theres alot of test fitting. i dont remember when i did it. but at some point, after u instal the gates, you need to reinstall the main shaft, and most of the gears, and 2WD shift fork, and slide the outer portion of the t-case in place. be sure everything shifts good. then measure where to cut the STICK OUT, from the rails. they can only stick out about 1/4" when shifted into 4H. otherwise they will hit the 4L rail in the range box.
this pic also thems them after they were shortened.

6)put everything together for another test fit. you now need your gates to line up. if they dont, but are close, you can use a file to get them exact. mine were dead on, and no adjustments were needed. again, note the lug i added after the fact.

one thing i want to mention, as it messed with me a few times. when these rails are out, they can be put in 180* out of phase. it will work properly, but your shift detents will not work correctly. be sure on the final install, that the SINGLE detent notch is to the INSIDE.
make sure everything shifts correctly and smoothly. i used a bit of 90w to ease the install.
and finally, a forward shift tcase, converted to a top shift, ready to be installed.

hopefully this will help others who dont have a top shift case, but want a dual case set-up.

Originally Posted by NE-89-4Runner

from my build:



fork shift getting ready for modification



pre weld:


fully welded up: