I got my Yukon 4.56 gears installed last week. Picked up my truck on Friday night. Have been following the recommended break-in procedures to the T.

Picked it up, drove the 17 miles to get back home. Let it sit for 4+ hours to completely cool down. Then took it out and drove to finish off the first 100 miles.

There is snow here in Anchorage, (A LOT!) and I was using 4x4, (for the snow, and to help break in the front gears...), and before I got on the freeway, I took it out of 4x4 the same way that I always do.

I noticed a slight whine, almost a humming whistle sound coming from the right side of the truck. Thought to myself this must just be the new gear sound.

Got the truck up to 65 MPH, whining sound was still there, then after about 4 miles, there was a "thump" sound and feeling, then the humming whistle sound went away...

Now if I drive it, and I use the 4x4 around town then turn it off like I normally do, I get the humming whistle sound at about 30+ MPH.

I haven't yet had the chance to call the install shop, (closed for the weekend), but was curious as to what I should do? I know this isn't right. I don't want to hassle the guy at the shop if it isn't something he did. However, I REALLY don't feel like having my new gears explode while I am driving around.

Also a little more background. When they pulled my front end apart, they said the original oil inside of it was white, said it was water contaminated. The shop hot tanked both diffs before they put everything back together.

So folks, any ideas?

 

Did you have chance to bring it back to the shop to diagnose the whining? I figured that would be the first course of action for you so I am curious to know what they had to say.

 

An iwe not funtioning correctly on the right hand side? You would think gear
noise would not thump and go away.But definitly take it back to the shop
and let them check it out because you never know,and gear swaps are not cheap.