57 Powerglide problem.

[Bruce B.]

My early 250 HP Powerglide car is finally finished and on the road.
It runs great (4360 FI unit) but during a long drive today I noticed the PG (recently rebuilt) slipping in high gear. I stopped for a few minutes, checked the fluid level (it was a little overfilled). Got back on the road, low gear seems fine but after a minute in high gear it would slip some when I gave it gas.
The trans fluid looks clear and not discolored.

Any ideas what the problem could be???

I'm wondering if the shift linkage could cause this problem if not properly adjusted.
Thanks in advance.

[Michael H.]

Re: 57 Powerglide problem.

I noticed the PG (recently rebuilt) slipping in high gear.

Hate to say it but that sounds like an internal issue. High clutch is failing for some reason.
If it doesn't slip in low or reverse, that means the pump and line pressure are ok.
Could be a governor issue but most likely a clutch piston seal leak or ring seal on the back of the pump.

[Roy B.]

Re: 57 Powerglide problem.

If your VARY lucky the filter seal may be leaking AIR or the band adjustment . Easy to replace or adjust with out removing the PG. BUT it could also be the banana seal or the clutch pack seal as Michael said which would mean removing the PG and open it.