Rear End Differential Assembly?

[bmwman1983]

My car is at the shop right now because there is a noise coming from the rear end. The mechanic says i need a new rear end differential assembly. where can i buy one of these? Any help would be very appreciated.

Thank You

[cali-ti]

someone on here may have a stock open diff for sale. otherwise, ebay or the wrecker yard. do you have a manual trans (3.45 diff) or auto (4.44 diff)?

[bmwman1983]

auto. so thats the technical name for it, open diff. thats good to know. are there any online shops that carry thses pieces or is used the only way?

[cali-ti]

well, it's unlikely that it's a LSD (limited slip differential). if you could find one, it would be a nice little improvement, but not likely to find one, especially for an automatic. you could get it rebuilt, but that will cost more than i used one i believe. if you can find one from a used 318ti or a used 1.9l z3, should bolt right in (same diff cover with one mount, same size, same ratio).

[bmwman1983]

so pretty much the best thing i could do is hit the junk yards and find a used one. thanx youve been a great help

[cali-ti]

also, the ratio should be stamped on a little metal tag that's bolted onto the diff cover and if it's a LSD, it should have an S on it as well. eg 3.73S (or S3.73, i forget which comes first). make sure you get a 4.44 otherwise you'll be accelerating slow as a turtle ;)

[stormos]

they are a biatch to find, found mine by sheer luck by emailing some guy selling an engine :)

good luck!!

[bmwman1983]

i found one on bavarian auto recycling with warranty

[cali-ti]

cool ... how much? did you by chance ask if they have any auto LSDs?

[campaiar]

I've got one from my auto (4.44) that I can sell you. I guarentee it will be cheaper than Bavauto's. Feel free to PM me.

[CirrusSR22]

Hey man, I did some research for you on www.car-part.com, a nationwide network of salvage yards. They list their entire inventories.

One of the cheapest on there is from a 6/96 Build Automatic 318ti, 4.44, open diff, no-traction control (not sure if traction control cars are any different).

It's at "Goldies Inc." slavage yard in Walpole, MA. It looks like its close to your city. 31 miles?

$200. Stock# C483.

http://www.goldiesautoparts.com/index.html

There's about 200 other used diffs nationwide on car-part.com if that one doesn't work out.

[DustenT]

I think "traction-control" refers to LSD on the older e36s, before ASC was available.

[bmwman1983]

i Spent $444 shipped to my door. i liked the warranty part so i went for it

[bmwman1983]

thanx Cirrus for the research i appreciate that

[GDB]

You might try looking on here for people that have done an auto to manual conversion since I doubt they kept their stock rear end in the car.

[campaiar]

You might try looking on here for people that have done an auto to manual conversion since I doubt they kept their stock rear end in the car.

Like me!!! :biggrin:

I still have it if anyone needs it. (Auto 4.44 open diff.)

[fly2thesun]

I know this thread is 4 months old, but I might as well add to it rather than start a new one.

I'm hearing a small hissing noise from the rear. It's quite small, barely audible below 40MPH. Above that, it increases with speed. Haynes manual says it should be due to worn differential.. If that's true, should I repair it ASAP? Or can I just keep driving until the problem becomes more serious?
( Right now it's not that loud even at 70~80MPH. I didn't notice it myself until my friend pointed it out. )

And when I decide to repair, how much can it cost and how hard is it to get the right parts?

This thread seems to imply the assembly is really hard to get anywhere regardless of price. Bavauto carries a few differential parts, but not an assembly. I hope this problem isn't too expensive or too hard to solve.

thank you

[CirrusSR22]

When I bought my car @97,000 miles it had a diff. that was making noise. It almost sounded like wind-noise, or a very-light howling. The place I bought it from put it on the lift and ran the car. They were 99% sure the pinion bearing needed replacing. I said don't fix it and they knocked a bunch of money off the price of the car.

When I drive slowly (<25mph) down a tight residential street with the windows down, I can hear a constant scratching/moaning/hissing sound. I don't really know how to describe it, but it's very light.

Well, 2.5 years and 141,000 miles later and the noise is exactly the same as it was before.

fly2thesun, on the freeway, does your noise vary with the amount of throttle you have in? On mine, when I use light throttle (to maintain speed) the noise is there, but when I lift off completely the car goes silent. It sometimes bothers me, but I guess I've learned to live with it.

I talked to a couple of transmission shops and they said a diff rebuild would be $250. Plus I'd be bringing in brand new bearing from BMW for another $90 or so. Probably $350 for a rebuild with new pinion bearings.....

[campaiar]

I still have the 4.44 open diff parts that I know someone needs. We're talking cheap here..

[fly2thesun]

I had a chance to test the car on highway today. ( student living on campus: highway driving is like once a week ) The noise is really inaudible up to 40MPH, and it kind of 'turns on' at 45~50MPH, and gets louder with speed. It is a function of only MPH, completely independent of throttle or RPM. So my symptoms are not exactly the same as CirrusSR22's, although very similar in other aspects.. Probably it's too subtle to diagnose without an expert mechanic actually hearing and seeing.. And too early to take an action when I'm not 100% sure what the problem is.. Anyway, thank you for the help, guys!

[fly2thesun]

I finally took my ti to a mechanic for a diagnosis of the humming noise from the rear. And they said "It's a common problem, but it's nothing serious. Don't worry unless it gets worse", just like CirrusSR22 said.. So I'm just happy with that... I would have been happier if I hadn't had to spend $190 to correct the well-known problem of the window coming off track.. Anyways, thank you guys for the advice and offer to help.

[andy]

One thing you can do is refill the diff with good synthetic 75W-90 - I revived my old diff with that. Worth a shot - cheap and easy - only takes a 14mm allen wrench and a minimal amount of jacking.

[fly2thesun]

Thanks for the suggestion.. I checked Haynes manual, and it indeed seems easy. Drain from one hole and fill from the other hole, making sure to not lose washers. But I have a few novice questions here...

Do you need some hose, syringe, funnel etc to refill?..
And how do I properly jack up? What kind of jack and/or jack stands do I need to get? How do I use jack stands to support the car? ( Do we still have to use the jack plug on the side of the car, as with the tire-chaning jack from the trunk? )

Please bear with me as I'm a nubee.. All I've ever done myself is 'sea foam' and nothing else.. ( Not even air filter or oil change.. )