Originally Posted by
bmorgil
Az I am assuming a lot about ob's transmission below. It sounds like it is not making any noises and it works well in all the gears except the second gear hop out. It is not grinding or having trouble shifting into second gear. I am not sure what is meant by "Notching" or "Shaving". The T90 should be rebuilt as specified in the repair manual. Back in the day or if high performance gear sets for drag racing weren't available, a modification to improve shifting speed and the ability to shift under power without the clutch, led to the removal of some of the clutching gear teeth. The best place for shift modifications like this however, is the shift collar and the race track of old.
I would definitely not notch or shave anything. Some of the information you hear can be very misleading. Some things are meant to shore up a worn transmission or not following rebuild specifications for wear. When a transmission is loose or sloppy, you can expect all kinds of shifting problems and noise in more than one gear. The engineering of the transmission is such that as it wears out it has a tendency to take parts with it. In other words as the gears wear and bearings wear and things start wobbling the clutching teeth will quickly wipe out their profile. So it is the chicken and the egg, in the end the clutching teeth will be bad if the gears and bearings are worn bad enough to wobble. Many people believe the detents and springs in the cover hold the trans in gear. If you have ever seen a shifter tied to the dash, and the transmission bend it (the shifter) spitting it out of gear, you learn quickly that no shifter detent spring will hold it in gear if the clutching teeth profile is worn bad enough!
I have seen some wild stuff on the You Tube. Some of it probably has the gear engineers rolling. Often great mechanics who can rebuild it in their sleep, may not have gotten the engineering explanation on how it actually works. I would not recommend any transmission modifications without a good engineering look over. There is a lot more science in there than you would think!