What would cause the transmission to all of sudden stop shifting to second gear. And has plenty of fluid.

 

If you are talking about a TH350, it happened to me 2 weeks ago. In my case it was just the vacuum line to the modulator had come off.

 

Number One answer for either TH350 or TH400. Never saw a TH350 lose 2nd that wasn’t low on fluid. They have huge diameter frictions and steels that seldom get burned up.

Maybe a slim chance that the plastic gear on the vacuum modulated has deteriorated and “apple cored” (in appearance). Then it can be no be turned by the drive gear on the output shaft, which is machined on the shaft.


Steve O.

 

I think so,and just out of curiosity where is this located underneath the car,if so during this time,a few hrs prior I was underneath it,and could have easily broke something on it.especially some type vacuum line.

 

Please do not continue to list threads with just “help” as the title. Multiple threads with the same title and no description doesn’t give members a reason to read them.

 

Ok,no problem,will give a more detailed title.