TH400 reverse slipping??

Hi all,

My th400 has done aprox. 1000 miles since a full rebuild (with manual valvebody). The other day I noticed that reverse seemed to kinda grab then let go then grab let go and so on. Its been doing this ever since.

At the same time, I noticed that when shifting to third, there is a short delay (maybe half a second).

I checked the fluid and it was a little low so I topped it up but the problem is still there.

Please tell me that this is a common problem and it can be easily fixed:( :(

Thanx heaps

rear band is slipping the pistons seal is bad in the accumulator had one that did that 25 years ago i am thinking that what it was

reverse and 3rd both use the direct clutch pack most likely the drum was worn where the case support sealing rings are. before you pull the unit there is a case support bolt thst could be broken or not torqued down #30 foot pounds. you must remove the valve body to check this. It has a 12 point 3/8 head on it you must remove the spacer plate also . good luck

yes i think that is rigth COOK67 thinking about it the seal was out of the center support direct drum