Morning, been awhile since I was here but need some advice/help concerning a 53 Olds 88 I just purchased. Previous owner shows receipt for overhaul and it drove okay for about 200 miles after I bought it. While driving around 60 it dropped out of 4th (high gear) and went binto super, I coaxed it back into high by speeding up and letting off the gas but it fell back into super again. Fluid is clean, no burnt smell, as I understand it high is clutches so band adjustment is not going to help, let me know if this is incorrect. Could it possibly be a valvebody or govenor issue? Does anyone know the procedure for cleaning or repairing those? I've built 350's, 400's, c4 c5 c6, Torqueflites but NEVER a hydramatic of this vintage. Any and ALL help would be greatly appreciated. I would also be interested in a good used unit or a rebuilt. thanks Rich

 

If this is happening in DR, then that is a problem. The only gear it should shift back in is S, and only after you slow down below 70mph or so.

It does sound like either a valve body or governor problem. However you may want to check the manual linkage to see if it is caught near S gear when in DR. And of course check the TV lever for proper adjustment.

If it were me, I would think something like the overcontrol valve in the valve body may be stuck. This is the valve that allows downshifts when in S position.