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Noise When Decelerating

tcrossno

By tcrossno
in Ask A GM Technician

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tcrossno New Member

tcrossno

Posted
Posted

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 Senior Enthusiast

ChevyTech77

Posted
Posted

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 New Member

tcrossno

Posted
  • Author
Posted
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 New Member

tcrossno

Posted
  • Author
Posted
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 Enthusiast

jimbrown1

Posted
Posted

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 Enthusiast

Chevy_fan

Posted
Posted

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 :thumbs:

John

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jimbrown1 Enthusiast

jimbrown1

Posted
Posted
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 :thumbs:

John

 

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

Chevy_fan Enthusiast

Chevy_fan

Posted
Posted

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.

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