Hello there and welcome to the BMW Car Club of America.

If you are a BMW CCA member, please log in and introduce yourself in our Member Introductions section.

Installed LSD now have bad drone

Discussion in 'DIY (Do-It-Yourself)' started by frito, Jan 13, 2020.

    • Member

    frito

    Post Count: 59
    Likes Received:15
    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,
    • Member
    • Technical Service Advisor

    charlson89

    Post Count: 2,330
    Likes Received:131
    Does the drone change when your on the gas or off?
    • Member

    frito

    Post Count: 59
    Likes Received:15
    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.
    • Member
    • Technical Service Advisor

    charlson89

    Post Count: 2,330
    Likes Received:131
    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.
    • Member

    frito

    Post Count: 59
    Likes Received:15
    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.

Share This Page