Tranny Problem

[lukecp]

I have been having a problem with the TH350 in my truck for the last couple days. After the truck has sat for an hour or two, and i go to start it up, when i try to put it in either drive or reverse, i will move the shifter to the gear, but it won't go in to either gear. The tranny will stay in park, but it wont engage. Then, about 10-15 seconds later, it will go into gear just fine. The tranny was rebuilt 3 months ago. When it does go in, it shifts nice and firm, and has zero other problems. When it is warm or when i drive it in the morning, it is just fine. I called the tranny shop where the tranny came from (Ace Trannsmission in Springfield, MO) they said that it was proably having some toruqe converter drainback, and that they would install a one-way check valve on the tranny, and that it should fix it. They said that it wouldn't cost anything. Does this sound like the problem that is making it not want to go into gear?

[magoo72]

wow i got the same issue w/ my th350 let me know what you find out

[COBALT]

What they're telling you doesn't sound quite right. What do they mean by "drainback"? Where would you put a 1-way check valve, and what would the purpose be in connection with the torque converter? Sounds like BS to me. If they're planning on putting a 1-way check valve in you valve body I'd like to know WHERE they plan on putting it.

What does sound like your problem is a bad front pump. It sounds like it's taking too long to build up enough case pressure to change the main valve actuator from P to D or R. Remember that fluid pressure makes any part of your transmission work, and if you don't have the right fluid pressure no shifting will take place.

Once it starts to shift ok, can you basically shift back and forth between D and R just fine (more than once in other words)? Is there any slippage in R? Any slippage in D? This may also be caused by excessive slip on your apply band (what helps engage R), or your friction plates, but you'd feel slippage after it engaged, but it doesn't sound like it's engaging at all.

Simple things you can do are:

1. Check transmission fluid at OPERATING temperature. Fire up the truck, and let it warm up, then move the selector through all gears, throw it in park and check the fluid. Is it full? Is there any maroon sludge on the stick?

2. Drop the pan and see what's in it. Any broken lip seals or pieces of debris?

[lukecp]

Once it goes into gear, the tranny works great with no slippage or any problems. I did check the fluid when the truck was warm and running, and it was nice and red, looked almost brand new.
Like i said, the tranny is still under warranty, so they said they would put the check valve in for free (didn't say where though, i will ask them when i take it up there), and if that dosen't work they will pull out the tranny.

I have never heard of the "drainback" valve either, and i'm not sure what it is, which is why i asked. Thanks for the help.

[73stepside]

when i check the fluid in my tranny, i put it in gear. i thought that was the way it's supposed to be done. i would check it in gear. i had this problem with my 66 chevy when i was younger and it turned out to be low fluid cuz they didn't fill the torque conveter when they gave it back to us. so it was a couple quarts low.