4.8is Front Differential Rebuild Kits
 

I strongly suspect the front diff on my E53 (PN: 31 50 7 512 665) is starting to whine and am looking at repair/replace options.

I've replaced my drivers side wheel bearing and axle with no resolve, leading to the diff being the culprit. The sound is peaking in loudness about once a tire revolution.

Does anyone know of rebuild kits that are available for the 3.91 radio front?

Are there places that will reman it for a reasonable cost?

Have you changed the fluid?

Curious to hear what you find here. When I was redoing my front diff seals which I had open for other work I found ton of postings on other X drive cars where the front diffs were blowing up often. I have not seen much posting of it here on X5s though so maybe not as common?

I suspect you are way past this as a help but on my recent refill of diff I did add Liqui Moly 2019 MoS2 Anti-Friction Gear Lubricant per suggestions of a few places. Cannot speak to how / if it helps drop noise since mine was not prior.
http://www.amazon.com/gp/product/B00CPL8UPY

As ref I used redline 75w gear oil http://www.amazon.com/Red-Line-57904.../dp/B000CPCBF0 in front and rear with that Mos2
Curious to hear what you come up with on front diff options too.

J

Not since I have owned it, When I changed the axle the fluid level was fine. Put about 6,000km since then.

Not the level, I meant draining old fluid and refilling with fresh dealer supplied fluid. It's pretty cheap. I would try that before anything else. I almost replaced/rebuilt my whining transfer case (as recommended by Indy and dealer tech) but decided to first drain and refill the fluid. The whining gradually subsided in a span of about 300 miles and then completely stopped. That was like 10k miles ago.

Yes, that is true. I'm planning to dive into that this weekend, not confident it will resurrect it though and want to know my options.

I'll check these out. Will likely do a flush a few times with cheap fluid to get out any particles which are likely in it due to the noise.

Don't throw out the baby with the bath water. Flush the fluid and refill with a quality one and go from there.

That's not the intention. I'm evaluating options..

Do a 30 minute drive at hyw speed then drain, this will remove more particles then several drain/fills.