from CTech by Torn.

"Im currently converting my AWD tranny that came with the 2nd gen 3sgte I used for my swap.

Converting the AWD to a FWD tranny is not as hard people would think, and when finished, it will be exactly as an MR2 tranny, except with the shifter cables already going in the right direction. Also, with this method, your center differential won't burn since it will be completly removed.

Goodies needed :

-Alltrac tranny.
-GT4 shift cables.
-MR2 turbo differential (open, OEM Toyota VLSD, aftermarket LSD)
-MR2 differential cover.
-Speedometer drive for the differential if it does not come with the diff.
-2 axles seals (optional, but recommended and cheap).
-1 set of alltrac outer axles.
-1 set of inner MR2 axle with passenger axle carrier (get LSD inner axles if going with the OEM Toyota MR2 turbo VLSD unit).
-A puller and access to a press to replace 5th gears on transmission.
-An Alltrac crossmember with the transmission rear mount (or modify your existing one).

I'll try to do a step by step guide (I will really need to post pictures later):

1 - Remove the transfer case by unbolting it from the bellhousing case. Inside this transfer case there is the gear that drives the propeller shaft (that goes to the rear differential). Also there is the center viscous coupling unit. Remove the transfer cases (3 parts) and everything inside. You won't need these anymore.

2 - Open transmission by removing 5th gear case. Remove 5th gears. Remove bellhousing case. Remove shifting forks. Finally you can remove the center/front differential from the bellhousing.

3 - Change drive axle oil seal from the bellhousing if your tranny has high milage (cheap at dealer).

4 - Buy an MR2 differential. I suggest getting an LSD unit, since opening that tranny is a pain and getting LSD with a 3sgte is a must IMHO You either can buy an open MR2 turbo diff, a OEM toyota VLSD diff, or better yet, aftermarket torsen diff. The MR2 differential will work perfectly in the AWD tranny. The bearings will sits nice and thigh.

5 - Remove ring gear from the AWD front/center differential by removing the 16 bolts, and tapping it with a brass hammer (or place a piece of wood and hit it).

6 - Place the ring gear on the MR2 diff, place the 16 bolts.

7 - Order a speedometer drive from Toyota dealer (cost me 80$ can, but I bet you can get a better price than that). Place the speedometer drive on mr2 diff.

8 - Install diff. If your AWD tranny grinds, and you'd like to replace the synchros for not too much, now is a good time to do it.

9 - Re-assemble the tranny: Place the input/output shafts, selecting gear forks, oil cooler lines, bellhousing case, 5th gear, 5th gear cover.

10 - At this point, you'll need the differential cover from the MR2 that will bolt on where you removed the transfer case. You can get this from a toasted MR2 tranny. This cover has the passenger axle seal. Replace it also if worn or old.

11 - Get MR2 turbo inner driveshafts. You need axle with turbo and LSD if using the OEM Toyota VLSD diff. Otherwise, if using open differential or aftermarket LSD (TRD, cusco, etc) use the normal turbo axle. The normal Mr2 turbo non-LSD axle can be modified also to fit the OEM Toyota LSD diff.

12 - You need to make hybrid axles. Use the celica alltrac OUTER axles, and the INNER MR2 axles. The outer axles is those that enters the hub with bearing at the wheels. The inners enters the transmission to plug into the diff. You can separate the outers and inners axles by removing 6 8mm Allenkey bolts.

13 - Install the new alltrac/mr2 hybrid tranny. Use the celica alltrac shifting cables, use either electronic or cable driven speedo by swapping the correct one on tranny. Use 3sgte clutch/flywheel/pressure plate. Place the alltrac/mr2 hybrid axles.

14 - The rear transmission mount will be different. This also happens if you swap the MR2 transmission. You need to get an alltrac crossmember, or modify your existing one (the mount is not at the same place).

15 - Drive

Ok I know this isn't a detailed step by step guide, but this should give a good lead to any of us that wants to convert their tranny.

Did I do it ? I'm almost done, I'm only waiting for the speedometer drive for the MR2 diff, then I can assemble back the tranny. I need MR2 axles also.

I'm pretty confident that this will work, and because I had a reltively low milage alltrac tranny laying around, this transmission will not cost me that much, but will be really solid, weight the same as an MR2 tranny, will be LSD with solid axles. I won't need to tackle with the shifting cables pointing in the wrong directions also

NOTE: Keep in mind that you should use the BGB to disassemble and assemble the tranny. Also this guide is intended for the 2nd gen 3sgte on a 5th st184 celica. However, this should work on 4th, 5th and 6th gen celica, and all version of alltrac AWD transmission but maybe with some minor differences.

Hope it helps someone. If anyone have corrections to make please go ahead!

-Phil "

here is the url CelicaTech