4L60E Trans Whine
 

00 Bravada 101K miles on it. It whines similar to a power steering would when it needs fluid but not quite that high pitched. It's constant does not change witht the rpm but does get louder with pedal pressure. Only does it in gear any of them. I'm thinking it's the trans pump I did read something about the EPC solenoid being bad can cause excess pressure making the pump whine but it doesn't **** hard. Any thoughts on this I have another week until I'm on vacation and I'm going to pull it and start replacing some parts and hopefully somebody here has seen or heard of this so I'm not wasting money on the wrong parts.

So it does not change with engine RPM, but does change with engine load...

Does it change with speed? or engaged gear in the transmission? Does it go away with engine speeds over 2500RPM while driving? Does it do it in all gears?

Does it sound like it is under the hood or under the truck? An alternator can cause a very similar noise. Try removing the serpentine belt and running the engine to see if the noise goes away. If it does, then it is one of the components on the front of the engine.

I also seem to remember a PCV valve issue causing some sort of noise on another member's truck. Replacing the PCV valve solved the problem. At under $5, it is a good place to start. You can pull the PCV valve out and shake it. If it rattles, it's still good. If it doesn't, replace it.

where is the solenoid-transmission control located.

The torque converter can cause this type of noise if it has gone bad. You definitely want to rule out the other areas first (alternator, other pulleys, and PCV) first before moving in that direction.

steveh, is your situation the same as the OP's? If not, it would probably be best to start a new thread.

Its probably time to change the fluid in the transfer case. The Bravada uses a different transfer case for the smartrack and it needs to be changed every 30k or so. It uses a viscous clutch fluid that you have to get a gm dealer. It's about 8 bucks a quart and uses 2 qts. If this is a first change you should probably change it, run it 10 miles or so and change it again. I did this to mine and it was a total different truck. No more binding up in parking spaces or trans whine.

I feel like an idiot now for the first time i actually drove it really slow with the radio off cause my father was in the car and I noticed that all the noise goes away in lockup. Usually I'm going so fast by that time I couldn't hear anything at all with the road, wind and tire noise. I'm trying to find a place to order me one at a decent price that will get here in the next day or two.

Problem fixed. Bought a new converter and pulled the trans out. It wasn't the converter is was that stupid O-ring on the end of the imput shaft. It was ripped. I still replaced the converter since I already bought it and I was there. Not sure why GM uses it that way I've never seen any other trans have an o-ring there.