th400 hesitates when cold

[87sierra]

okay i have a 1987 gmc sbc350 with th400 that when cold will hesitate to go either forward or reverse but when up to operating temp will engage forward or reverse right away which at first i thought it was seals but the hesitation should get worse another thing someone told me was that there might be a torque converter check ball or valve that is open and bleeding pressure from the tq

 

[chengny]

Don't mean to ask stupid question but, did you change the oil/filter.

Over time the ATF gets contaminated and, as designed, the particulates get caught in the filter. Eventually the filter gets coated and slows down the flow of ATF from the sump to the pump.

Warm ATF, being less viscous, can still easily pass through the plugged up filter.

However, when the ATF is cold , it's viscosity is increased. The pump will have trouble pulling it through the filter and establishing line pressure. As it warms up, the problem fades away.

I hope it is something easy like that.

 

[87sierra]

I changed the filter and fluid two years ago and have only put 30,000 miles on since then so there is a possiblity that could be my problem but I don't think it is as the oil is still red in color I think it could be the valve that changes fluid for forward and reverse