1991 Chevy Truck Whining when I get up to 40+mph

CARI1976

MEMBER
1991 CHEVROLET TRUCK
V8
4WD
MANUAL
16,500 MILES

Hi, I hope you can help me. My question could lead to troubleshooting various things.
My 91' truck has been having a humming or whining from the transmission area or possibly the drive train area. I just did a tune up about a month ago and changed the tranny fluid today. It just started doing this about a week ago. It doesn't whine when I downshift, only after I get up to speed.

I'm tired of dumping money into this but I feel like when I'm done it will be a new truck again.

Thanks!

4 Replies

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

When you are at highway speed and you back off the throttle dose it change pitch or is the whine about the same, dose is alter if you go on and off the throttle a little when at speed?

Mark (mhpautos)

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Sunday, August 15th, 2010 AT 4:15 AM

CARI1976

MEMBER
3 POSTS

It stops when I take my foot off the accelerator. And when it does whine. It's consistent but I can really only hear it if I go into a tunnel. It's not so loud in the cab.

Cari

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Monday, August 16th, 2010 AT 7:39 PM

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

this sounds like a diff whine, a wheel bearing will not back of with the throttle, a diff will, I would have this checked first.

Mark (mhpautos)

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Tuesday, August 17th, 2010 AT 1:38 AM

CARI1976

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3 POSTS

Thanks! I had a 50/50 feel on if it was the brakes or diff. The breaks were next to get fixed but if it's the diff that different. I can fix the brakes. Not the diff.

Thanks! I"ll have it looked at. I had a gut feeling it was the differential.

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Tuesday, August 17th, 2010 AT 10:41 PM