[N8N]

2009 E92 335i 6MT, mostly stock except for maintenance parts and a VRSF intercooler.

Are these diffs rebuildable? Apparently mine is bad, guessing it's the passenger side bearing. Are parts available for these? Who would you have do the work? Is anyone doing LSD conversions on these with the welded ring gear, or if I'm thinking of that would it be better to source an older, bolted diff for a core?

thanks for any advice. I wasn't expecting this but apparently my car is forcing me to address this issue. Kind of frustrating at only 150K miles and I actually had the fluid changed when I got the car at about 75K miles because I don't believe in "lifetime" fluids and figured that would help it last forever. Meanwhile the Chrysler 8.25 (and that one is a factory LSD) in my Jeep with 300K miles is fine; when I changed the fluid in it this spring (I bought it at about 250K and who knows service history) it looked awful but still works great.

[whyzee125]

Originally Posted by N8N

2009 E92 335i 6MT, mostly stock except for maintenance parts and a VRSF intercooler.

Are these diffs rebuildable? Apparently mine is bad, guessing it's the passenger side bearing. Are parts available for these? Who would you have do the work? Is anyone doing LSD conversions on these with the welded ring gear, or if I'm thinking of that would it be better to source an older, bolted diff for a core?

thanks for any advice. I wasn't expecting this but apparently my car is forcing me to address this issue. Kind of frustrating at only 150K miles and I actually had the fluid changed when I got the car at about 75K miles because I don't believe in "lifetime" fluids and figured that would help it last forever. Meanwhile the Chrysler 8.25 (and that one is a factory LSD) in my Jeep with 300K miles is fine; when I changed the fluid in it this spring (I bought it at about 250K and who knows service history) it looked awful but still works great.

Yes, they're rebuildable. If it were me I would probably buy a pre-assembled LSD and just send yours back as a core as setting up diffs correctly is pretty difficult. M factory, Quaife, Wavetrac, and Drexler all make LSDs for this platform. I think M factory also sells a rebuild kit if you just wanted to rebuild yours and leave it stock. There's a couple shops that also offer the un-welding service separately even if you don't use their LSD but I can't remember the name of them. Some searching on here would probably get you to the answer, I recall seeing one fairly recently.

[Gee-Dog]

I also thought I had a noisy diff (in a 2009 E92 335i DCT), and replaced the diff with a used (but guaranteed) one - it was a bit quieter but still very noisy. The supplier of the diff replaced it for me (including installing the replacement) and the noise was still there. Turns out it was a wheel bearing making most of the noise. We had spent a lot of time trying to locate the noise, including opinions from a few mechanics, and everything pointed to the diff.
Your noise may well be the diff, but try and be certain before rebuilding or replacing it.

[N8N]

Originally Posted by Gee-Dog

I also thought I had a noisy diff (in a 2009 E92 335i DCT), and replaced the diff with a used (but guaranteed) one - it was a bit quieter but still very noisy. The supplier of the diff replaced it for me (including installing the replacement) and the noise was still there. Turns out it was a wheel bearing making most of the noise. We had spent a lot of time trying to locate the noise, including opinions from a few mechanics, and everything pointed to the diff.
Your noise may well be the diff, but try and be certain before rebuilding or replacing it.

Sadly, he already replaced the RR wheel bearing which we both thought was the problem...

Amazingly, I find that my neighbor had (because it's in the back of my Jeep now) the original diff from his 135i because he upgraded it to a LSD at ~35K miles. Now I'm thinking I might do the same once I get my car driveable again, because I'll have a core that needs work anyway...

[N8N]

Just to follow up on this, I just picked my car up today, with the "new" diff installed. Noise is gone. So, while we all, myself included, assumed that the noise was a rear wheel bearing, it wasn't - it was the diff gone bad.

Any opinions on diffs online? My neighbor spoke very highly of them, he has one of their custom LSDs in his 135i which is why the original diff from that car is now in my 335i. Thinking I might as well see if this one is at least a good core.

[335i54n]

you dont need an lsd for a stock car, better suspension and tires

[N8N]

I don't need a bigger intercooler or a Cobb AccessPort either, but here we are

[whyzee125]

Diffsonline will be fine, it's not one of the more commonly used vendors for this chassis but they're a reputable company.