Hey all this is my first post, im looking forward to knowing you all, currently I've got a slightly modded 09 37x sedan. After Dyno tuning about a week after I had some howling coming from my front end, I laid the car up for a few months and saved and now got it to a shop, I am being told I have bearing failure in the front diff, the mechanics told me a whole new diff is cheaper than replacement parts and rebuilding the diff, thoughts? Also is this a normal problem with The AWD front diff??

 

The front diff on a X has I believe only 4 bearings in it: x2 for each side and a front pinon and a rear pinion bearing. The bearings I imagine are pretty cheap but the labor could be painful. Taking out the diff is a big deal, but the rebuild should only be 1-2 hours if even. I don't know how much a new diff is but I find it hard to believe its cheaper then a rebuild.

That said if your if your going to be switching out the front diff I would volunteer to be the site's guinea pig and get a front diff from a 2008 G35x 5 speed auto with the 3.692 final and switch out your rear diff for a 3.692 LSD. Be the first X owner with a 3.692 7 speed. In theory it should work, but the hardest part is changing the front diff out. Just food for thought.

Also, I've been reading everything I could find about the X models and their quarks, this is the first time I read about an issue with the front diff. I would be concerned with what caused the failure as well. Bearings typically do not go out without a cause for the wear.

 

So for an update, I ended up just getting a stock diff I drove it for 5 minutes, got it to 50 mph and noise returned and is same as when I brought in, don't know if mechanic made a mistake or if I'm having another problem. Car is back at shop now will update with further progress

 

please tell me your changing to 3.69? I've wanted to do this for sometime! An he had to drop the motor to do the front diff correct?

 

No I am not going to a new ratio, and no he did not have to take the engine out, a skilled mechanic can do it without the need for that, I read a lot of mixed reviews on whether or not the engine needed to come out. However mine was never pulled and my diff is now brand new, and to UPDATE it is running perfect now

 

TF - So what did they do, or not do to fix the noise, please?

Last we heard, you had a new diff, but the noise was still present at 50 MPH. Tires? Hubs? Ground squirrel?

Sean

 

Lol they ended up replacing the front diff again, ended up being a fault part or faulty labor they say part but who knows lol, what I do know is the diff I have now is brand new and works fine, so this is diff number 3 and all is fine, 100 miles on car so far