2005 Grinding Noise

[Bergy9]

I am new to the site, and I have searched for my issue with no luck. We have a 2005 Yukon that has a grinding noise that can only be heard from inside the truck. The noise is present in reverse, low speed, neutral, at speed while coasting. The rear brakes are brand new, with less than 20 miles on them, along with rear axles seals being replaced. Nothing was said about issues with the rear diff. On the front axle I had a leaking right axle seal, so I replaced the bearing and seal. The noise was still there, so I checked the left side axle, had some play, so I replaced the left seal & bearing as well. Still have the noise, when I dropped the diff. oil I had junk on the drain plug which was a grease like, but had a metallic shine. I have no play, or sound when the front end is off the ground, no wheel play, to eliminate the hub bearings. I dropped the front drive shaft off, to check the pinion bearing for play, nothing. One shop checked the diff's and found no noise, so they immediately said tranny. The fluid off the dip stick is clean, smells normal, and to me with the noise present in neutral this would eliminate the tranny. The brake pads up front are all the same thickness. I am at this point thinking carrier bearings in the front, but have read the noise could be in the drive line, or even the front brakes as well.

Thank You in-advance
Dave

 

[z0lt3c]

Is it a Denali? The transfer case problem is much more common on the AWD drivetrains, which would only be found on a Denali trim. The sound is much more of a whining then a grinding, so that doesn't sound like a good match. Usually when I think grinding I think of parking brake adjustments and/or brake dust shields. Can you tell what general direction the grinding is coming from? Do you feel any vibrations through the steering wheel or seat?

 

[Bergy9]

Not a Denali, just a 1500 5.3l, with the following options for the drive train: NP8 - transfer case active, two speed, push button, GU6 - rear axle 3.42 ratio, G80 - posi traction, limited slip, with a M30 - 4L60-E tranny. The noise seems to be frontal in nature. I would think if it was brakes you could hear it outside of the vehicle, but you can only hear the noise when your inside the truck. I have been on the running boards when moving, I've hanging off the back, and I can not hear the noise, it has driven by me and no noise.

---------- Post added at 09:45 AM ---------- Previous post was at 09:35 AM ----------

As for the brakes, the noise appeared and it was definitely a rotational rubbing/grinding noise. The brakes I think locked up on my wife in a drive through, so we had it towed home. I pulled the rear brakes and found that approximately one third of the drum brake surface was shinny, as if the parking brake had been dragging. Since that we had the rear brakes and rear seals replaced. On the brakes that was the rotors, calipers, pads, and a fluid flush.

 

[Bergy9]

Ended up lifting the rear end, and put it in reverse, and the noise appeared. Dropped the front drive shaft and again the noise was there. Very loud at the tranny & xfer case area. Finally took it to a Tranny Shop, and it's the planetary bearings. A side note is that the truck locked up, similar to the brakes locking up and she was able to get it moving again. Will know soon if its a rebuild, or replace depending how much if any metal made it into the system.

 

[z0lt3c]

Bummer to hear it's the transmission, from what I've read the 4L65E is pretty solid by the 2005 model year. As an FYI I priced out some rebuilds in my area and I was able to find a new rebuilt transmission, installed, for just under $1000. Surprised at how affordable it was.