Transmission Whine

[Desert Yeti]

Hey all, a question for you:

First, the truck:
79 K5, 350, TH350, 203 (part time kit)

Second, the problem:
It has just developed a whine that seems to be coming from the area of the torque converter. The whine varies with engine speed, but is unaffected by rolling speed (it whines when in Park sitting still).

I've visually inspected the flexplate and converter and see no signs of issues. The tranny is full of fluid and shifts nice and crisp. It was run for a week low enough on fluid that it slipped when it was cold and then when I topped up the fluid seems to be when the whine started and got progressively worse over the last few days.

After searching on here, I suspect the tranny pump, but haven't been able to figure out if a pump whine is only when it's in gear or if it also makes noise in park...

Ideas about how to further diagnose would be invaluable!

Thanks!

 

[throttleissues]

The pump spins and moves fluid any time the engine is turning, so yes you would still get a whine in Park. There's still a possibilty of converter damage from running low on fluid (mostly to the one-way clutch in the stator)

 

[Desert Yeti]

Thanks man! Do you think a pump in the process of going bad would make a whine but still allow the tranny to function correctly? Is there any way to diagnose this further short of pulling the transmission out of the truck?

Next question, I'm guessing the pump and/or converter can't be replaced with the tranny in the truck...? I've never worked on an auto tranny before, but I'm ok with a wrench and would give the repair a shot if it didn't involve dropping the whole tranny/tcase out of the truck.

Thanks again for your thoughts on the matter!

 

[throttleissues]

It's possible it could whine without complete failure, like a p/s pump does. It's not a real common failure on a th350 from what I've seen, but running low on fluid could definitely cause a problem like that. The only other tests I can think of is to check system pressures, but that's not a sure thing to show the problem if the trans is stil working normally. And, yes, the trans has to come out to replace torque converter and pump. The pump housing is the first component in the case and is held in with a ring of bolts right behind the torque converter. Torque converter just slides off, but must engage with multiple components when installed, so push turn it until it stops dropping into the pump.

 

[Desert Yeti]

Thanks again! I really appreciate the help!