Whining Noise in the Rear End

[twiget]

I have a 1990 Suburban 2500 2WD. Yesterday I got in my truck and as soon as I got above ~30mph I got a really loud whining noise, sounded like gears running with out proper lubrication. When I dropped below 30mph, the noise went away. I accelerated back up above 30mph and it started again. Fortunately I was headed home, so I limped home at 25mph. I drove the truck around today to try and figure out where the noise was comming from, and not a peep.

The first thing I checked was the tranny fluid, which was full. The previous owner installed an after market tranny cooler, and there is a small leak on the radiator, but I've known about that since day one and kept the tranny fluid full.

The noise is definately not comming from the engine, as it only happened when I was moving. I went through the service manual, and it seemed to indicate that the problem might be a worn pinion bearing in the rear end.

Any thoughts?

 

[hammermachine]

Noise

My Blazer makes a noise, which I believe is the fuel pump in the tank. It whines constatly, I will have to replace it next year. I don't know what the problem you're having is. sorry.

 

[mnstrburbon]

My rig is making what i think is the same noise, it does it at weird speeds and acceleration more than deceleration. I also think its in the rear end its a humming whining sound combined.

 

[Thunder]

Have you checked the lube in the rear axle? It would be a good idea to change it too.