Noise When Decelerating

tcrossno · December 17, 2010

03 silverado, 1500 z71 4x4 5.3l 130,000 miles. there is a whining sound which increase in pitch with speed, not engin rpm. And when i let off the gas going down hill at highway speed i get a jerking or surging and a rubbing noise. I have replaced both front bearing hubs (lots of slop), drained and refilled all fluids, checking for excessive shavings, have no movement in drive shaft, front or rear. I do have worn tires and if it whas just the wining I would say that is the problem but with the other stuff i know it mechanical, any ideas other than differentals, t case?

ChevyTech77 · December 17, 2010

Honestly? It sounds like it is stuck in 4WD due to a bad t-case encoder motor sensor. Take the

encoder motor off the side of the t-case and drive it again to see if its any different.

tcrossno · December 17, 2010

Honestly? It sounds like it is stuck in 4WD due to a bad t-case encoder motor sensor. Take the
encoder motor off the side of the t-case and drive it again to see if its any different.

have already replaced sensor(different problelm) a couple of months ago 4wd working properly,

I will give a try though, a pretty simple task.

tcrossno · December 20, 2010

Honestly? It sounds like it is stuck in 4WD due to a bad t-case encoder motor sensor. Take the
encoder motor off the side of the t-case and drive it again to see if its any different.

tried this weekend, no difference, any other ideas

jimbrown1 · December 20, 2010

Mine just started the same thing, with only 46K miles and just had the TCCM replaced last month. I'll be curious what you find out.

Chevy_fan · December 20, 2010

I had the same type of noise and it was the T-case. I have a 03' 2500hd with the 6.6 with the allison. What i found on the net is the 246,261 and 263 T-case have a pump rub problem due to the fact that the case is made of Magnesium and the pump is made of Alum. climb under the truck and look for a small hole next to the webbing where the tail shaft starts( about 2 inches from the parting line of the case) I have included a pic of what mine looked like. and if you don't see any hole take a couple pieces of long rubber hose and attached it to the vent tube of the trans, and T-case and Diffs. and run them up in the truck and drive down the road listening to each and that may helped find the problem. Also I got all my parts from High Gear they are the cheapest I found

John

jimbrown1 · December 20, 2010

I had the same type of noise and it was the T-case. I have a 03' 2500hd with the 6.6 with the allison. What i found on the net is the 246,261 and 263 T-case have a pump rub problem due to the fact that the case is made of Magnesium and the pump is made of Alum. climb under the truck and look for a small hole next to the webbing where the tail shaft starts( about 2 inches from the parting line of the case) I have included a pic of what mine looked like. and if you don't see any hole take a couple pieces of long rubber hose and attached it to the vent tube of the trans, and T-case and Diffs. and run them up in the truck and drive down the road listening to each and that may helped find the problem. Also I got all my parts from High Gear they are the cheapest I found
John

I assume it's OK to still drive the truck with this noise, it's just annoying.

Chevy_fan · December 23, 2010

well I drove mine for about 100 miles or so. That way I would not have to pay for a tow bill. Well it has costed me bout 700 so far. Don't know how long it will last? If there is isn't any fluid in it for sure.