I have a 1955 Oldsmobile 88 with a 3spd hydramatic and the transmission isn't staying in third. Once I push the throttle no matter how hard or soft I apply it slips back to second. I think its the coupling on the pressure lines and need to know where to get replacement parts.

John

 

We are all kids, just some of us are older. Welcome, hopefully someone more familiar with that trans will help you out. In the meantime how about some pic's.

 

A 1955 HydraMatic is a four-speed unit. Sure it's not just downshifting back to third? Sounds to me like the throttle valve rod needs adjusting and there are several folks on here who are very familiar with this transmission. Look for coldwar and d2willys and they'll have a good idea why your HMT is misbehaving.

You can get HMT parts from Fatsco or Edwards Transmission so they're no trouble to find.

 

Thank you for the point in the right direction rocketraider. I put an album with a few photos on my profile oldcutlass.