97 K2500 whining noise

[unreconstructed1]

OK guys, here's a problem I'm having and I really ain't sure what it is. when I step on the gas in my K2500, there is a strange whining noise , but when I let off the gas, the noise stops. I really don't believe that it's the rear end because the frequency of the whining changes pitch. it doesn't whine when I first get started, but usually starts when the tranny shifts to second. I thought it may be the exhaust, maybe a broken hanger... I checked and the bushings are pretty wore out. could it be the torque converter? If so, is there any way to check without actually replacing it?

[mountie]

Originally Posted by unreconstructed1

OK guys, here's a problem I'm having and I really ain't sure what it is. when I step on the gas in my K2500, there is a strange whining noise , but when I let off the gas, the noise stops. I really don't believe that it's the rear end because the frequency of the whining changes pitch. it doesn't whine when I first get started, but usually starts when the tranny shifts to second. I thought it may be the exhaust, maybe a broken hanger... I checked and the bushings are pretty wore out. could it be the torque converter? If so, is there any way to check without actually replacing it?

Man-o-man...... Hard to tell from just reading your post.... I have an '88, but I have experienced many issues during the life of my truck, having 364,000 miles... there are a few different reasons for a "whining"......

The location source is important. it could be anything from the torque converter, forward pump in tranny, a bad planetary in tranny, or just the power steering pump, or something else powered by the serpentine belt?

Any sort of vibrations??

( an after thought)...... What the heck is that tranny part I am thinking about ( you mentioned the shifting)..... I don't know if your tranny is similar to mine, but I am thinking about the ( let me look in my service book)..... Ah, ha..... The Governor (in tranny) may be going..... I keep a spare in my truck, and it can be replaced in 20 min, even on the side of the road.

( additional info)...If it is the governor, the noise is usually due to the worm gear ... The part is accessed from the r/h side rear of 700R4 after removing a cup/cover. The part has weights that spin, from it's nylon worm gear that can strip. The part is about 4" long. It is serviceable, but a new one is easier. When the part fails completely, you have to rev the heck out of the engine to get it to shift into 2nd, ..then the tranny just coasts.

[unreconstructed1]

Well, that's why I don't believe that it's the rear end. The noise seems to be coming from under the cab, I believe on the passenger side, since it's louder on that side.

The transmission is a 4L80. I don't have a vibration, just the noise. I'm not really sure if the shifting is a symptom of the noise or not, since there are other issues ( the PCM isn't getting a signal from the VSS).
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[mountie]

Originally Posted by unreconstructed1

Well, that's why I don't believe that it's the rear end. The noise seems to be coming from under the cab, I believe on the passenger side, since it's louder on that side.

The transmission is a 4L80. I don't have a vibration, just the noise. I'm not really sure if the shifting is a symptom of the noise or not, since there are other issues ( the PCM isn't getting a signal from the VSS).
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I may have given a too long of a response about the tranny......
But..... If there is anything I know about automatic transmissions, is this :

If the tranny does ANYTHING that is not normal ( different from what you are used to when driving your truck)..... something is wrong with the transmission.

Or.. something is causing the transmission to be wrong.

But..... you have a noise coming from "down there".....

Suggestion..... SMELL THE FLUID.... sense if it is burned.