Installed LSD now have bad drone

My rear end blew out and I made a huge mistake of taking it the transmission shop that had recently rebuilt the rear end in my Avalanche vs. to my regular BMW guy. Dumb, dumb, DUMB.

Anyway, I had them install a Turner LSD. After I got it back I am getting a horrible drone above 60 MPH with it really bad around 75. It has a slight vibration too. The source of the drone seems to be coming from the front of the car. When I took it in for the follow up they replaced the driver side rear axle (which I replaced 14,000 miles ago). He also said he thought it was the front wheel bearing which I also replaced 14,000 miles ago. Luckily I caught him before he installed them and I replaced them again. Long story short, it made no difference. The guibo looks solid and it looks like it was hooked up right based on the arrows. Any ideas what the probable source might be?

Thanks,

Does the drone change when your on the gas or off?

Let's try this again - original post had a bunch of phone related typos.

The drone doesn't change when I let off the gas. As a test to see if the exhaust wasn't sealed properly I got it up to around 70 -75 where the drone is the worst. I then put it in neutral and let off the gas. The drone only changed once the car started losing speed from being in neutral. Otherwise, the drone stayed constant. It seems to only change as the speed of the car changes vs. throttle input.

Ok, I would recommend putting the vehicle up on a hoist and drive it on the hoist with the traction control off. Then using a long screw driver see if you can isolate the noise to either rear wheel bearings or rear diff. Doubt the axles are causing the drone since that would change with throttle input. A constant drove would have to be only a component that spins at vehicle constantly. So drive shaft, rear diff, wheel bearings, very unlikely but transmission.

Thanks Charlson. I have it back at the shop now. I'm suspecting that they either didn't line up the driveshaft in the same position when doing the center support bearing or they didn't preload the csb. I don't think it will be the wheel bearings as I did those summer of 18 and they sounded fine before the rear end blew. I guess we also could have gotten a faulty differential. I bought a fully assembled unit. Thanks again for the feedback.

Let’s us know what you find out.

Definitely, will do. It is still at the shop that installed the diff. I made a bad, bad decision not using my "regular" BMW guy or at least trying it myself.

Now I'm sweating bullets because I've been reading over on E46 Fanatics that BMW is trying to buy back older cars with the Takata airbag. There is a new open recall on mine (I had it replaced a few years ago) for the "permanent" fix. Either mine is not of the age that they are buying back or I'm going to have some strong pushing to recoup a lot of the funds I've sunk into over the past couple years, expecting to keep it forever. undefined

I haven’t had one bought back yet from not being able to get the airbag parts.

I called the Transmission shop for an update yesterday since I haven't heard anything in three weeks. They now have the owner and founder of the shop working on it (I've been working with the nephew and presumed heir). They are putting in shims. I assume this is to address angle issues. My stupidity for not originally taking it to my regular guy cannot be understated.

Update: After shimming it, which the shop feels they shouldn't have had to do, they said it's still vibrating. At this point, they think they have a defective unit. They are going to toss in a used differential to confirm this theory. If confirmed. they'll work with the manufacturer to get a replacement unit.

Wow if that fixes it how unlucky that would be.

Yeah, but I'll take unlucky if that takes care of it. It'll also renew my confidence in the shop a little bit since it was a whole unit we ordered, not just the guts.

Update: I just got off the phone with the shop. They put in the used differential and said it is running silky smooth. Turner on the other hand is giving them the complete runaround. They have a ton of hours into shimming it, trying everything to take care of the vibration just for it to be defective from Turner. Turner is telling them they use a different place to actually assemble the units and it's on them. I know Turner is an advertiser with the club which is how I found them and recommended them to the shop. Are there any club resources available to lay some heat on them to make it right for both me and the shop that has an inordinate number of hours into this?