Transmission Rebuild

After owning and driving an AE92 GT-S for a few years, a vast majority of you will have noticed that, sadly, the stock C52 transaxle isn't quite as over-engineered as the 4A-GE engine. Typical problems that have plagued the transaxle include, but are not limited to:

• 5th gear pop-out
• Synchros that prematurely wear out and lead to 1st, 2nd, and 3rd gear change "crunches"
• Gear whine/noise
• Notchy shifting
• 1-2 shift fork failure (Note: This problem was more prevalent on the pre-'88 AW11 MR2s)

These problems are compounded when you subject the drivetrain to even more harsh abuse such as drag racing, SCCA Solo events, open track events, and all-out club racing. Some people that I know keep C52 spares that have been rebuilt and blueprinted for just this reason.

You have a few options once you decide you've had enough of the current tranny:

• Buy a Japanese surplus tranny for $250-$400,
• Buy a new C52 assembly from Toyota for about $1800. Part number 30300-12440,
• Find a local shop to rebuild your tranny. I shopped around and got a price range of $600 (your average "hole in the wall" shop) to as high as $1500 (true race shop) for labor only, not including parts that may need to be replaced,
or
• Rebuild it yourself.

Since I always like learning new things and never pass up a challenge, I chose the last option. I figured, "Hey... I can do motors. Why not learn how to rebuild trannies?.." Plus, the money that I'd save by doing it myself could be used on some tools that I could use again. I did a fair amount of research, bugged some people who rebuilt the C52 themselves, and finally bought the parts, materials, and essential tools needed for the tranny rebuild project.

Just a word of advice, though... If you don't feel comfortable taking apart an engine--let alone assembling and actually getting it to run right!--I caution you about taking on this project. There are just too many parts that look similar and are press-fit onto the shafts. The shifter's shaft mechanism alone can easily confuse someone. Also, if you're not ready to pay a good amount of money for the essential tools necessary for the job, you'll have a difficult time and break expensive parts in the process.

The SSTs and their respective part numbers are listed below. The only source for the SSTs is SPX Corporation, OTC. The dealers go to them as well. If they ask you for your dealer code, just tell them that you'll be buying as a general public account. Contact info is as follows:

SPX Corporation, OTC
28635 Mound Rd.
Warren, Michigan 48092-3499
800.933.8335

You'll find some pics on the next few pages of the more interesting portions of the project. You will not find the detailed step-by-step instructions on how to rebuild the C52 tranny. You'll need the factory service manual for that. As far as I know, no other service manual covers the rebuild in detail. What I will do is point out some things that will make the disassembly and assembly processes more manageable.

Essential Tools

• Factory service manual
• Copies of the "MX" section for the AE102's factory service manual--the diagrams are much nicer
• 12- or 20-ton hydraulic press, $200-$250
• 09564-32011-01 SST, differential bearing preload adapter, only for OE open diff, $14.40
• 09309-12020-01A SST, 5th gear replacer, $112.79
• 09950-00020 SST, bearing separator, $210.83
• 09213-36020 SST, 5th gear puller, $313.45
• Inboard axle stub from an AW11 MR2 so you can set the diff bearing preload, essential if you're going with an LSD
• Dial indicator with 0.01 mm (0.001") resolution
• Dial indicator magnetic stand
• 27 mm socket for output shaft rear nut
• 6 mm hex key
• Torx bit set (for the input shaft, throwout bearing collar)
• Feeler gauge set
• 0-1" micrometer
• 1"-2" micrometer
• V-blocks for shaft run-out
• 1/4" torque meter (wrench) with 0-15 in-lb (inch-pound) range, Snap-On models TE1A, TER1A, or TEC1A; ~$350.00
• 3/8" torque wrench with 80 ft-lb max range
• 1/2" torque wrench with 150 ft-lb max range
• Dental picks
• Brass punches
• Steel punches
• Magnetic pick-up tool
• (Digital) camera to take pictures of the teardown process so you don't screw things up

Parts

• 90521-26004 Inboard axle snap rings, QTY: x2
• 90311-25011 Input shaft oil seal
• 90311-34028 Seal, oil, transmission case (LH axle seal)
• 90311-34016 Seal, oil, # 2, transaxle case (RH axle seal)
• 96711-24030 Speedo shaft sleeve O-ring
• 33367-12110 1st gear synchro, production dates 8708-9104
• 33367-12050 1st gear synchro, production dates 9104-9106
• 33367-12110 2nd gear synchro, production dates 8708-9104
• 33367-12090 2nd gear synchro, production dates 9104-9106
• 33368-12020 3rd gear synchro
• 33368-12020 4th gear synchro
• 33369-12030 5th gear synchro
• 90365-25021 Input shaft front bearing
• 90363-25048 Input shaft rear bearing
• 90365-33005 Output shaft front bearing
• 90363-25067 Output shaft rear bearing
• 90366-38004 Differential front bearing
• 90368-38010 Differential rear bearing
• 41222-12040 Differential locking plate, QTY: x4
• 90101-11353 Differential bolts, QTY: x8
• 90179-18005 Output shaft rear locking nut
• 00295-01281 FIPG seal packing for tranny case

Optional Parts

• 90364-38007 Bearing, needle roller, 1st gear
• 90364-32014 Bearing, needle roller, 2nd gear
• 90364-31002 Bearing, needle roller, 3rd gear
• 90364-29002 Bearing, needle roller, 4th gear
• 90364-24006 Bearing, needle roller, 5th gear
• 33481-12040 Gear, speedo drive (in case you have a new LSD and don't want to bother pulling off the old diff's bearing to get the speedo drive)
• 90341-18006 Filler plug, QTY: x2
• 90430-18008 Filler plug gasket, QTY: x2

Optional Upgrades

• Starter relocation to the intake side
• QUIA 94.309.155 Quaife Automatic Torque Biasing LSD, $1075
• Redline MTL or MT-90 gear lube
• Royal Purple Max-Gear 75W90 gear lube

Other Materials

• Torco MPZ assembly lube
• 4"x4"x12" oak (or other hardwood) blocks, to be used as spacers when pressing the gears off the output shaft
• Simple Green