jetech

My 77 T350 auto seems to take to long to shift to 3rd. When I accelerate hard the tach goes to 4500 rpm before it finally shifts into 3rd. This process takes what I feel is to much time. There is a definite bog from around 3000 rpm and 4500 rpm before the car shifts and accelerates.

Is there an adjustment? Any ideas if it could be something else :confused:

Thanks for any help.

jetech

anyone!!!! :confused: :confused: :confused:

Kid Vette

Check for a vacuum leak.

The timing of shifts on a TH350 is controlled primarily by the vacuum modulator and governor and to a lesser extent by the downshift linkage. The governor usually is either working properly or not at all in which case the transmission wouldn't shift at all. The two common things that go wrong with the governor is the gear stripping and the governor valve sticking.

The vacuum modulator helps time shifts according to engine load; when the engine is under load the vacuum is lower and the transmission will shift later. If there is a vacuum leak, it will be interpreted by the modulator as load on the engine and the shifts will occur later. Possibly the vacuum modulator needs to be replaced. If you disconnect the vacuum line from the modulator, turn the modulator upside down and transmission fluid runs out where the line was attached, then the modulator is leaking and should be replaced.

If the downshift cable is way out of adjustment it can also change the timing of the shifts. You might try disconnecting the cable temporarily and see if the shift point changes.

Hope this helpS!

jetech

Kid Vette
Thanks for the ideas. I will check these items.