Uncommon for diff to brick at 60k miles?

I brought up the conversation over at bimmerforums as well, but my shop is telling me that my rear diff is toast and they need to replace it. It's on a 2004 325 sedan with an SMG; I've not heard of differentials failing at 60k miles so it shocked me that this would be the case.

How common a problem is it at low miles? Further, how long would you estimate it taking for a problem like this to develop? There was a leak at the pinion seal that started the investigation, but I can't be sure how full (or empty) it was for how long, and while I've only had it about 4 months and 7,400 miles, I'm 1.4k miles outside the dealer's warranty on it so I'm not sure they're going to do much to help.

I've never heard of a diff failing on a non-M n/a E46 period. Did your car break down or something?

I heard from the guy that bought my sedan that the diff failed 12k miles after I sold it. I told him the seal was leaking and he said he would get it fixed ASAP. Well, he didn't and it ran low on fluid. It also was pushing 175k miles when that happened.

so whats wrong with the diff? is it seized?

It's not seized, he said after they sealed it up again and drove it a few miles they pulled burnt diff fluid out again. I had been driving it 60 miles a day until i dropped it off and hadn't noticed an issue.

I honestly want to go in in the morning, have them put it up on a lift and show me the bad guts, b/c I can't imagine how it's failed with so few miles, nor in only 7400 miles if they claim it was a nonexistent problem before they sold it to me.

E46Mango, it didn't break down, no. I'm presuming they haven't torn it apart and just had the cover off, frankly it hadn't felt like a problem before.

He's telling my $800 for a replacement used diff "through their distributors" and 5-6 hours to replace, though he'll "give me a break" and do 2 hrs... I've never dealt with anything behind the firewall before so I'm at a loss for experience, but I'm feeling like, until I start looking power or something, that I'm not really needing to have this repaired today. Frankly I'd been starting to look into planning mechanical upgrades, and I'd rather not buy a new used diff then want to upgrade it in a year again.

Unless, of course, I can get them to do it free under the warranty I'm beyond miles on now...

They do go bad sometimes but if it does you will know it. Mine started with a limping feeling. Like the car was surging. It took about a month after it started that then it went out fully. It would go about half way around and then clank real hard and go half around again. That's what happens when they go out. I went on ebay and ordered a used one for $150 plus shipping and it took me about 3 hours to change it and I am no mechanic. Found a good diy on here and went for it. It was easy. In my opinion if your diff goes bad you know that something severe is wrong and if you couldn't tell then I think they are trying to screw you. Take it somewhere else and get a second opinion.

That's very early for a diff. They are fairly strong unless you do a lot of burnouts in the ice and then maybe a spider gear.
But if it leaks and gets low you usually notice the diff making noise or hum/howl.
A used diff can be found for $250 fairly easy. It's about 2-3 hrs labor at most from an independant shop.

On a side note. If you have SSG(aka SMG-1) then really be sure you know what's to expect when that transmission pump goes out. It's an expensive fix and recently a dealer charged a guy $8K to fix.

I don't think it's an SSG - it's a 6-speed, not 5, though I may be quite mistaken on the differentiations. But I've definitely read about the increased costs. I needed a car (the last one pretty much fell apart around me) and this one was the best option at the time... I'm not sure that I want to keep it long enough to see that fail, haha.

But the motor and transmission are very solid, so I'm glad about that.

I'm going to go in tomorrow and just ask them to give me my car back. I have some other things to get on them about so it'll be a fun morning. But yeah I wasn't feeling any problems before, so I had better not be feeling anything when I get it... in the end, there's as much a potential they're trying to take me for a ride.

Originally Posted by Alex323Ci

That's very early for a diff. They are fairly strong unless you do a lot of burnouts in the ice and then maybe a spider gear.
But if it leaks and gets low you usually notice the diff making noise or hum/howl.
A used diff can be found for $250 fairly easy. It's about 2-3 hrs labor at most from an independant shop.

On a side note. If you have SSG(aka SMG-1) then really be sure you know what's to expect when that transmission pump goes out. It's an expensive fix and recently a dealer charged a guy $8K to fix.

Originally Posted by lutze

It's not seized, he said after they sealed it up again and drove it a few miles they pulled burnt diff fluid out again. I had been driving it 60 miles a day until i dropped it off and hadn't noticed an issue.

I honestly want to go in in the morning, have them put it up on a lift and show me the bad guts, b/c I can't imagine how it's failed with so few miles, nor in only 7400 miles if they claim it was a nonexistent problem before they sold it to me.

burnt? means theres heat so probably something is not adjusted right.

I don't currently have a garage unfortunately, I'm not sure how happy they'd be with me jacking the car up in our parking lot

But yeah I'd have no problem tearing it apart myself and may just end up doing that. He was getting on me about it being a 4.5-5 hour job, and $800 for a used diff they're probably going to pull out of a junk yard? Mmhmm. Plus they just had half of it apart for me so it shouldn't be a big-big deal, just have to find a friend with a garage I can use.

I appreciate sharing your experiences, everyone, it's helping me feel like I have a better control of the situation.

Originally Posted by dude dog

They do go bad sometimes but if it does you will know it. Mine started with a limping feeling. Like the car was surging. It took about a month after it started that then it went out fully. It would go about half way around and then clank real hard and go half around again. That's what happens when they go out. I went on ebay and ordered a used one for $150 plus shipping and it took me about 3 hours to change it and I am no mechanic. Found a good diy on here and went for it. It was easy. In my opinion if your diff goes bad you know that something severe is wrong and if you couldn't tell then I think they are trying to screw you. Take it somewhere else and get a second opinion.

Here's a link to a lot of info on the differential. How to search and buy, which ratios might be an upgrade, and how to install yourself. Hope this helps
http://www.bokchoys.com/differential/diy_diff.htm

Thanks!

Yeah, it's the words he used, though they have a way of assuming you're just an idiot when they talk to you so I'm not confident he really explained the problem accurately.

Originally Posted by jasonbimmer

burnt? means theres heat so probably something is not adjusted right.

There is no way a dif should have gone at that milage. Even if youve never changed your fluid they often last longer then the engine does.
Often when they do start to fail they only need a new gear.

I'm going to find out what's actually up when I go in this morning - the dude was being evasive on the phone and I just don't have a good feeling about the interaction. There didn't feel like anything wrong with it before I took it in and I'm more and more guessing he thought he could take me for a ride.

Originally Posted by DHK

There is no way a dif should have gone at that milage. Even if youve never changed your fluid they often last longer then the engine does.

Also, use this as a chance to change the diff ratio. The x3 came with some nice ratios.

Drewfus, I was thinking that. I'm going to pick it up today instead and will take my time and find a good deal on something

Originally Posted by E46Mango

I've never heard of a diff failing on a non-M n/a E46 period.

Same here, I never heard of this. My guess fluid leak that was ignored by previous owner.

Originally Posted by Lionelski

Same here, I never heard of this. My guess fluid leak that was ignored by previous owner.

Thing that gets me in this is it's the shop I bought it from, and in their negotiations gave me the internal build list of what they all did before putting it on the lot. Hurried in the list a bit is a quart of 75W90, which after looking a bunch the last two days is the diff fluid. So they filled it up, which means they saw what they should have seen was a leak or evidence of one, but didn't do anything about it, diagnostically or otherwise. And now, first time I have it in after my "warranty" is out they tell me I need to change it. Yep.