Clicking / Rotational Noise from Front End

[OR VietVet]

The first time the diff fluid is ever changed can show some silver because of the sharp edges being worn down from driving. After that the fluid should remain pretty clean except for darkening from normal use. Once that silver reappears, that means something is letting go. You do need front diff work.

 

[AggieZig]

So small update... I drove the Tahoe a few miles over the weekend and noticed a pretty strong burning rubber odor. After that, I decided it probably wasn't safe to drive to the diff shop as it's about 30 minutes away and I'd have to get on the freeway. I decided to take the front half shafts out so that the diff was not spinning (yes, new Timkin gen 3 roll formed bearings that do not need an axle shaft).

Here's the thing... I still have that freaking noise even with the half shafts disconnected. I'm beside myself here. As I understand it, in 2HI with the front CV's disconnected, nothing should be spinning the front diff?

 

[OR VietVet]

I think at this point it is something that a trained qualified differential guy needs to diagnose and then get back on here and let us know what is what.

 

[AggieZig]

I think at this point it is something that a trained qualified differential guy needs to diagnose and then get back on here and let us know what is what.

I don't disagree with you but don't really want to drive the truck to the shop with the noise and smell. I was hoping I could get temporarily solve that by taking the diff out of the equation.

 

[clandr1]

Going back to the transmission replacement here... If he removed the transmission, he would've had to remove the transfer case. Is it possible he reinstalled the TC in such a way that caused undue pressure on the front differential?

Makes me wonder if taking it back to the transmission shop is the next step here, since it's too coincidental that this noise started right after you received the truck back from the shop who replaced your transmission.

edited to add: If you take it back to the transmission shop, I would play dumb and tell them you're assuming it's something related to the transmission job. I wouldn't volunteer that you've done everything with the half shaft removal, bearings, etc.

 

[Fless]

So small update... I drove the Tahoe a few miles over the weekend and noticed a pretty strong burning rubber odor. After that, I decided it probably wasn't safe to drive to the diff shop as it's about 30 minutes away and I'd have to get on the freeway. I decided to take the front half shafts out so that the diff was not spinning (yes, new Timkin gen 3 roll formed bearings that do not need an axle shaft).

Here's the thing... I still have that freaking noise even with the half shafts disconnected. I'm beside myself here. As I understand it, in 2HI with the front CV's disconnected, nothing should be spinning the front diff?

If you have the AUTO 4x4 then the transfer case is always spinning the front propshaft, I think, even though the diff actuator is not engaging the diff. Pull the front propshaft and see if the issue persists. And I'm not sure if the transfer case will leak with the propshaft out.

 

[AggieZig]

If you have the AUTO 4x4 then the transfer case is always spinning the front propshaft, I think, even though the diff actuator is not engaging the diff. Pull the front propshaft and see if the issue persists. And I'm not sure if the transfer case will leak with the propshaft out.

This is 100% accurate. I did not realize that but I went ahead and pulled the front driveshaft out and the noise is gone. So, it's definitely the front diff and now I feel comfortable driving it to the shop knowing I'm not tearing it up further!

 

[Fless]

This is 100% accurate. I did not realize that but I went ahead and pulled the front driveshaft out and the noise is gone. So, it's definitely the front diff and now I feel comfortable driving it to the shop knowing I'm not tearing it up further!

Curious if the T/C leaks any fluid with the propshaft out?

 

[AggieZig]

Curious if the T/C leaks any fluid with the propshaft out?

I read that it should be fine. When I pulled the driveshaft out, I did not see anything that would indicate I was compromising a seal by having it removed.

 

[Fless]

Thanks; I've had mine out but didn't drive it like that. If you have the NP246 TC be sure to use Auto Trak II fluid in it; it's blue.