Th400 1st gear issue

[SunSoaked]

Occasionally, after coming to a stop the trans feels like it disengages as if it slipped into neutral. Revving the engine doesn't do anything. Sometimes it will "catch" and go thru the gears normally. Other times I have to put it in park or reverse to get it to move again. It doesn't feel mechanical, it's very smooth and fluid related I think. Fluid level is good. Otherwise, it runs great. Maybe a solenoid or governor issue?
Thx for the help.

[YoungPup1977]

Does this only happen while in the drive position ?

On a TH400, the only solenoid in the trans is used for detent, and the gov pressure is based on road speed.....thanks,

[SunSoaked]

I don't know the history. I bought this truck 2 years ago and haven't driven it much due to all the work I've been doing to it. The pump seal leaks but has improved since I began driving it occasionally. I recently dropped the pan, changed the filter, dipstick grommet and vacuum thing on the side (lol- name slips mind). When it does this, putting it in reverse doesn't help. Sometimes I have to put it in park and back to drive. Other times, I'll just sit and idle for a minute and it will "catch" and return to normal. Otherwise its fine thru all the gears. Maybe a sticking valve? It feels like it just disengages.

[YoungPup1977]

Qq

[SunSoaked]

Completed the Vintage Air system today so I went for a few drives. Not once did the trans do it's thing. Until next time...

[YoungPup1977]

Thanks . Good Luck !!!