We are bringing our first 5 speed to T-Hill.
The 3T40/TH125 automatic has been a weak point throughout. Even beefed up with valve body changes and 'locked up all the time' torque converter, we've killed three transmissions in the Cavalier since 2007. They've never failed to a 'can't drive' state, but after the 4th place at Detroit '07 it had to be driven onto the trailer, since it wouldn't roll at all even in neutral.
The thing with LeMony automatics is the shift frequency. Every shift puts heat into the clutches/bands that takes time to remove, and these tracks are too tight for the most part to give enough time to recover. Lots of cooler helps, but there's usually no way to remove heat from the clutches fast enough.
So set your transmission up to shift just short of driveshaft breaking hardness and don't allow it to shift too many times per lap. If you have a way to lock the torque converter all the time, do it, since that keeps the converter from adding heat to the fluid and limiting the torque multiplication during shifts helps the clutches survive.
I think an American RWD 3-speed (904-727/TH350-400/C4-6) can be set up to live forever in racing conditions, but I don't hold much hope for any of the Borg-Warner or ZF Euro transmissions...
2x Volvo PV544 (RIP '63) B20 power!
2007/2012/2013 Driver's Championship (what was I thinking!?) 145 races and counting.
5/18/24