Thread: TH350 2nd gear slip?

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Have a TH350 with a shift kit for the street behind a 350, about a 2400 stall converter. If I leave it in drive it shifts normal. (up shifts and down shifts). If I'm cruising along and drop it into 2nd from drive, give it some gas-like when passing someone -the motor revs up and the trans slowly slips into gear, like when a standard clutch slips. Once it slips into second it stays without anymore slipping until I go back to drive and back into 2nd again. All other shifts seem fine. The trans was fine for about 3 years, this started happening about 2 years ago. Doesn't seem to have gotten any worse. Just annoying when trying to blow the doors (um ah) I mean pass someone carefully.

Any trans experts have an idea what might be the cause of this?

Thanks
REJ

Try one thing first and get back to us. Adjust the modulator with a pocket screw driver in until it seats. This will help us determine where you need to go. Even try back the screw out a whole bunch. See if it changes anything. I feel you have a modulator line pressure drop at the time you don't need it. Only a hunch, but worth turning a screw to tell us. We have many techs here that have a variety of experience to head you in the right direction.