Vibration and moan

gator007 · 09-15-2009, 02:36 PM

I have a stock 05 CCSB 4x4 LLY
When driving down the road between 1800-2000rpm's and between 56-60mph I get a slight vibration that you can feel in the seat and through the gas pedal with an accompanying moan that is annoying. At no other speed or rpm is this present. Does anyone know what this might caused by? I don't want to keep driving it if this might be a problem. Any help would be great.

**Hook'em_Horns!** · 09-15-2009, 03:28 PM

Moan or Howl with the vibration at that speed can be indicative of worn gear probs in the rear end.

How many miles are on the truck?

What are your service intervals for the rear end?

When was the cover off last?

gator007 · 09-15-2009, 03:46 PM

The truck has 95k. on it. I bought it about 4 weeks ago with 94k. All the miles on it are highway miles. I don't know when the last time the rear was serviced and I haven't done anything to it yet. I have all the paper work and any service that was done to the truck from the original owner and I cannot see where anything was done to it.

**Six-Gun-Todd** · 09-15-2009, 03:48 PM

With that title I figured this would have been in the "Lounge" section

gator007 · 09-15-2009, 03:50 PM

Quote:

Originally Posted by Six-Gun-Todd

With that title I figured this would have been in the "Lounge" section

I wish that was the case. It would definetly make me feel better.

**Hook'em_Horns!** · 09-15-2009, 06:30 PM

Service intervals when towing is 30k miles, you’re probably overdue. Simple (and cheap) to do, and it’s an opportunity to inspect for any gear damage there.

Raise and support the rear axle (chock the front wheels from rolling, as you'll be spinning the rear to inspect the gears). Recessed drain plug at the very bottom of the housing, then pull the cover for inspection. You’re looking for pieces of metal, chipped gear edges and such. Clean out all the black/burnt fluid residue with some spray brake cleaner and let dry. Add 3 qts or so (3.7?) of Mobile-1 75-90w to refill.

Fresh fluid won't cure a howl from the rear. But, rule out any damage there first, then next will be to inspect the driveshaft assembly.

gator007 · 09-15-2009, 07:36 PM

It sounds like the vibration and moan is comming more from up front maybe in the engine compartment. It almost acts like when the torque converter locks up. I'm not really sure. I will take your advice and change the rear axle fluid and inspect the gears that way I can rule that out and do a service at the same time.
Thanks for the reply

**Hook'em_Horns!** · 09-15-2009, 08:11 PM

Any gear noise can resonate forward via the driveshaft. 4wd? Service the front also, 2qts.

gator007 · 09-15-2009, 09:14 PM

Quote:

Originally Posted by Hook'em_Horns!

Any gear noise can resonate forward via the driveshaft. 4wd? Service the front also, 2qts.

O.K. thanks I will go ahead and service both.

gator007 · 11-03-2009, 10:17 PM

Ok, so I changed the fluids in the rear and front and everything looked good. I also changed all the other fluids while I was at it. Made no difference. I even put a new set of tires on. I still have the deep moaning vibration sound at 1600-2000 rpm's. Don't know what to do.