Transmission issues on 76' Camaro

I got a 76' Camaro that has a problem of going from the 3-4 gear to 2nd gear at random times. (Never does this when I am slowing down, only when I hit around 2500rpm or 60 mph) It also only does this when the car has warmed up.(usually about 40 minutes of driving)I cleaned the modulator and replaced the transmission filter and plan to clean the governator once I get off work. The transmission is for a 350 and is automatic with a shift kit and I was wondering if anyone knows what to do. (It still down shifts when speeding, after cleaning and replacing things, I was told that the transmission is fine cause if it was going bad it would do it all the time not just when warm.)

It could very well be the transmission itself. Whoever said it would do it all the time and not only when warm must not know much about cars.

The 350 is a 3 sp, no 4 th. Down shifts are controlled by the governor, or 3-2 kickdown by the throttle linkage to the trans.. When did it start doing this, when the shift kit was done?

The 350 is a 3 sp, no 4 th. Down shifts are controlled by the governor, or 3-2 kickdown by the throttle linkage to the trans.. When did it start doing this, when the shift kit was done?


Suprisingly no, it shifted just smoothly until about a month ago and we didn't mess with the transmission or anything related to it. Only put in a new Cam and lifters. Could a governor go bad and cause it to act like this?

Ok, had the top of the engine apart, go thru the the kickdown linkage adjstment

New cam = potential different vacuum. Checking that governor and modulator would be a good idea, as well as verifying the kickdown linkage adjustment as Max recommended.

Wear in main shaft seals, actuator pistons, and valve spools CAN affect shifting as the trans temperature increases.