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

1991 CHEVROLET TRUCK
16,500 MILES • V8 • 4WD • MANUAL
Avatar
CARI1976
  • MEMBER
  • 3 POSTS
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!
Aug 14, 2010 at 4:05 PM
Advertisement
Avatar
MHPAUTOS
  • CERTIFIED EXPERT
  • 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)
Aug 15, 2010 at 4:15 AM
Avatar
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
Aug 16, 2010 at 7:39 PM
Advertisement
Avatar
MHPAUTOS
  • CERTIFIED EXPERT
  • 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)
Aug 17, 2010 at 1:38 AM
Avatar
CARI1976
  • MEMBER
  • 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..
Aug 17, 2010 at 10:41 PM