Here in Part 1 we will be disassembling the 2003 Toyota Celica GTS C60 transmission and comparing parts to the common C50 5 speed. The bell housing on the C60 has a different starter orientation and the rear mount attachment is different. We are hoping the 6 speed parts can be installed in the 5 speed case, making it a direct fit. The tools required to disassemble and service these transmissions varies, and gears can break when stressed in the wrong areas. Armed with that information, please proceed with this project at your own risk and consult a transmission specialist if you are not comfortable. Now, Lets get started:
We start by removing the end cap, exposing the 5th and 6th gear components. This is the hardest part of the disassembly, you need to knock out the keepers and use pullers to remove all of these parts. You need the proper tools, penetrating oil, and a torch to complete this part of the job. First you need to remove the shifter rod from the case:
Remove the shift bracket attachment point and the end cap, then just pull the rod out paying attention to it's orientation and springs. Then you want to reach into the case and pry up both the 1-2 and 3-4 shift rods, locking the gears together. Now you can start pulling off the 5th and 6th components:
Once you pull off all of the gears you can then knock the keepers off the shift rods and remove the rear bearing plate. There are snap rings holding the bearings to the case that need to be expanded to remove.
Next you can remove the shift rod detent springs and balls under these covers. Use a small pick and a magnet to remove the parts from the case, then remove the reverse holder screw and case bolts (don't forget the 3 bolts inside the bell housing).
Now we can start comparing things, of course the gears are different but the forks and rods look the same as the C50. The shafts are longer to accommodate the 6th gear, but otherwise the look identical to the Scion xD shafts. Reverse looks identical, no surprise there. Lets keep going, remove the reverse gear and shaft, then the linkage. Remove 1st and 2nd shift rod detent spring and ball then grab both shafts and the rods together and wiggle them up and out of the bell housing. You can then just lift the differential out of the bell housing.
Now is the moment of truth, will all of these fancy 6 speed parts fit in a C50 bell housing and case? I believe they will, I've compared the two cases and the only differences are: 1-C50 has a reverse lockout(removable, no big deal). 2-pinion shaft bearing size in the bell housing(can be changed, no big deal). This is great news, we can keep moving forward with this project! Stay tuned for Part 2 where we will address some issues we found with the 6 speed synchronizers, and thoroughly inspect all the gears and bearings. We are still unsure on what axles we need, but that can be dealt with later.
I'm aware this may be an ancient discussion, but since Im just now entertaining the idea of a 6 speed swap (I'm going to assume you've seen the Teaser Video) ...lets take a look at the numbers for a minute. A lot of modern sports cars have 6 speeds, so they must be better right? Maybe....or maybe not.
To learn the technical answer we need to first consider our engine, and additionally each of us may have a different idea of what's "best". So lets look at our 2ZRVIOS. We have a Toyota 2ZR-FE Dual VVTi engine making 139HP @ 6000rpm/131FTLBS @4100rpm. You can see here that our power band is from 4100rpm to 6000rpm, so we need our gearing to keep the engine speed in that range. Now if you can remember our ARtrackbox build, a Yaris C50 transaxle with the Cusco Type-RS LSD and a Scion 4.3 final drive. This transmission has awesome acceleration and provides flawless grip under all racing conditions. Aside from its limited 5th gear, the C50 ratios are a perfect match for the 2ZR-FE.
In the early years of my vehicle modification, I would buy the flashy $60 gauges from AutoZone and install them in an A-pillar pod. Back then it was more about how I wanted the car to "look", than about gauge accuracy or reliably. Then at some point I upgraded to Autometer gauges, I bought a mechanical oil pressure gauge from PepBoys for about $70. Install was easy and it lasted a long time, about 3 years. Until one day the oil line broke from heat in the engine bay and I had a massive oil leak. After that experience I went to ONLY electric gauges, still Autometer brand. In January of 2016 I did the 2ZRFE swap on the Yaris and Installed a NEW Electric air core oil pressure gauge for $80-$90. This gauge worked great and the install was not bad, except that they don't include wiring with the kit and you need to make your own. Not a big deal. We daily drove the 2zrVios for 6 months and raced it every month, putting 10,000 miles on the swap (and the gauge). In June the car was down again for the Cusco LSD/4.3 final drive. In January of 2017 the car was complete and out racing again in February, but it was no longer daily driven. Then in April the gauge started shutting down randomly, I assumed it was a loose connection some where and just forgot about it. A few races later the gauge was completely dead. I removed it and checked voltage and resistance, the wiring is all good so I call Autometer. They tell me to do a few tests but I can't because the gauge will not power up at all, so now I have to send it in for a "pro-rated repair cost". Um...how about no, Im done being cheap.
Here in Part 3 we will diagnose and repair the cause of the suspension noises and the torn axle boots. Now that the engine has been returned to a fully operational status, it's time to do the same for the suspension. You may remember from Part 2 that the axle boots are torn and throwing grease everywhere. I called Toyota and got an estimate for all 4 boot kits, and for everything needed it was going to be $92. Anyone that has pulled the axles on a V6 Camry knows this is a serious job, and most of the time the carrier bearing gets damaged during removal. So in an effort to save myself some work and get all new parts, I went with new axles instead. The driver side axle is easy but I tried everything to get the passenger side axle out; penetrating fluid, heat, air hammer, very large pry bars, and even the trick to break the bearing race. Nothing worked, so I unbolted the carrier, jacked up the engine, and removed the whole mount and axle as one piece. I then had to take it over to a vice and use a very large hammer to pound the axle out of the carrier . Then finally, success.
We left off Part 1 with me taking the car on its first real road test in several years, and that revealed some issues. The next day after the car sat overnight, the coolant level had dropped significantly. I did a cooling system pressure test to 19psi and it held for 5 minutes, only showing a small drip at the upper radiator hose. I removed the old clamp, cleaned the oxidation, installed a new clamp, then tested again. There are no further leaks, so where is the coolant going over night? This always sets off alarms in my head thinking its a bad head gasket, so I attached the coolant no spill funnel and filled it to the 1/4 mark. I then ran the engine until it was fully warmed up and raced the engine several times, No bubbles at all. The oil looks ok, coolant looks ok, so lets check the cap. Its a Koyorad, it seems to fit right and holds pressure, and the vacuum valve is not stuck. So I ordered a new cap from Toyota as a test, and BINGO the coolant is now being pulled back into the system from the reserve tank. Great, that was an easy fix. Since I know the cooling system is in good condition, lets replaced the fluid.