OK guys, I've had trouble making the actual webpage, so I uploaded the pictures and you can read a short version here. I suppose if you don't understand completely you can post your questions and I will try to explain better as well as update this post with the better explanation.
First of all, there were many attempts to fix the onweway gear stripping problem. Almost all failed. I had to send my car to a machinist to find out why.
I had previously installed the bearing shim but my car would still strip gears occassionally. After contemplating my plans to install TC3 gears, he simply asked why hasn't anyone just pinned the pinion gear to stop it from deflecting away from the ring gear? I replied-they have!! His answer was that I was 90% of the way to fixing it because I had already shimmed the bearing. The problem needed more than one repair. The shim didn't totally fix it and neither did pinning the pinion gear to the shaft, but together they make it as strong as any TC3 gears!! Actually, IMO, the Surikarn gear support or the Penguin R/C gear support should also be used because of the poor design of the gear mount on the oneway housing.
Now that we know how to fix it, here's the list of things you will need:
- #53 .0590" drill bit
- .0620" piano wire
- dremel with good cut-off wheel
- CA glue
- dial or digital calipers
OK, now for the good stuff-
Step 1- remove your front diff or oneway leaving the pinion in place. Also remove the motor for easy access to the spur and spur adaptor.
Step 2- Using your dial or digital calipers and holding the driveshaft all the way forward with two fingers, measure the depth of the shaft in the pinion gear. Now push the driveshaft toward the rear of the car and take another measurement in the same fashion. Take your two measurements and average them together to get the center of the depth throw that the shaft uses.
Step 3- Now remove the motor mount screws and move the motor mount and spur gear forward enough to let the spur gear adaptor pin fall out of the driveshaft. This will allow you to remove the driveshaft completely from the car. Using your calipers to correctly set the pinion over the shaft in the same place it normally rides in the car (the measurement you came up with), CA the pinion into place with a very small amount of glue. If you have the time to wait for it to dry, use Shoe Goo. It is easily removed.
Step 4- Now use the #53 drill and drill a hole through the center of the pinion and shaft in the middle of the flat area where the pinion bearing rides. I personally drilled mine parrallel to the keyed area on the shaft, but I think it might be better to drill the hole perpendicaular to the flat keyed area. The pinion bearing will retain the pin you will install now.
*I went back and removed the pinion and slightly elongated the holes I drilled in the pinion to allow the pinion even more freedom to find a happy place. I do suggest you at least break the CA glue seal so the pinion gear isn't in a bind. This is the reason I stressed a SMALL amount of glue. If you have the time I would suggest using Shoe Goo instead.
Step 5- Now cut the pin with your dremel and grind the ends so it doesn't stick out past the plastic of the pinion gear just like the picture. Slide the pinion bearing over the shaft/pinion assembly to make sure it doesn't drag on the newly installed pin.
*******You have now pinned your pinion to the shaft.********
Next you must shim the pinion bearing so it doesn't "float" in the transmission housing. This is easily done with a thin metal tab used to build commercial and industrial battery packs. These thin tabs are usually spot welded to the ends of the batteries as opposed to the way we solder them. The spot weld is much stronger and more permanent. These weld tabs can be purchased at Radio Shack but I'm not sure they are the same size as the ones I have. I'll try to get by RS and check ASAP.
First cut the tab to 3mm wide (the width of the pinion bearing) and then wrap it around the bearing.
Now cut the shim so it doesn't quite wrap fully around the bearing. I left about a 3-4mm gap.
Drop the shim into the bearings's seat and then carefully work the bearing into place making sure the shim stays around the edge of the bearing.
*I worked mine in from the gap side and after it went in once and the shim took shape, the bearing goes in fairly easy now.
Now you can reassemble the drivetrain. Slide your shaft/pinion gear assembly through the shimmed bearing and through the motor mount/spur and into the rear diff housing. Now drop the spur adaptor pin into place and slide the spur back along with the motor mount and bearing. Reinstall the motor mount screws and front diff. If you have previously shimmed the diff so that it is tight against the pinion you must reshim it so there is a small amount of lash. This will free your drivetrain immensely.