Intermittently, 727 will not move in forward or reverse gear. Filter has been replaced, all bands have been properly adjusted to specs listed in Chilton manual. Car shifts firmly when operational in all gears. Trans has deep pan with filter extension. Never know when it is not going to move. Only happens about once in a while. Stock floor shift. Car is 1969 'Cuda. Does this sound like a problem I can get to just taking the pan off? Or does this sound like removal of H-pipe, trans, and a rebuild? Let me know if you need anymore info...

Thanks

Sounds like a valvebody problem? I would take the valvebody out and totaly disassemble it, clean and blow it out then reinstall and try it.

maybe the front pump..

I would start by checking your line pressure and servo pressure, to me if it has good line pressure then the pump is probably good and then I would suspect a valve body problem.

Does this happen only after sitting a long time ? ... like over-nite or longer ?

As was suggested earlier ...a pressure check is in order.

Well this is just a guess but it may be because of too much heat in th trans.
I kno it had caused mine to stick in 1 gear for way too long, like 1 - 2 minutes after refiring and driving down th road.
Soo is your cooling system keeping everything cool, Eng & trans ?
Do you hav a trans temp gauge ?

How do you get the car to move again once it has stopped going into gear?

Not sure. After a while it just goes. Sometimes 10 seconds...sometimes 5 minutes...sometimes it just never goes...then when you start it the next day it runs like a champ. Last night when I posted, it would not move after 15 min of screwing with it. Woke up this morning, hit key, fell right into gear, took for a test drive where it shifted great and chirped 2nd gear. Wasn't a heating issue because it was also cold last night and would not move. I usually let it idle in neutral before it goes into gear, and it has plenty of fluid. Just never know when (or where) it will happen.

Intermittant problems (in anything) are usually the hardest to diagnois. Besides disassembly and cleaning the valve body, you did the other easier stuff. After that a complete rebuild to eliminate a funky seal, ring, etc.

Sounds like the convertor is draining back. Might be a mismatched pump. Try parking the car in neutral and see if it still happens.

In my mind, it has to be something common to reverse and drive so that would eliminate the clutch packs and bands or sprag simply becasue reverse uses one band and clutch while Drive use another clutch and sprag. I don't think there's anything in the converter that would cause this type of intermittent problem unless as was stated already, it's draining back and not filling for some reason. But, one would think this would be more prevalent after sitting for awhile. I'd suggest trying a different valve body and failing that, it likely will have to come apart. Maybe the drive lugs on the pump are broken and they jam occasionally enough to drive the pump and then break free again. A stretch but my guess it is in the pump circuit somewhere. One other thing comes to mind. The rooster comb and lever that moves the manual valve in the valve body is known to break loose from it's serrations. This would cause this problem and would not be noticeable until the pan was dropped.

blow out the passage holes in the case and check the low reverse valve for small burr