Oem differential broke! Help me which one to get?

Basically my diff is gone. What are my options if i want to upgrade? I dont want to pay 1k on a used diff when i can upgrade. I seen the OG giken for 2k but i heard too many bad things about them. Whats good?

There's nothing bad about an OS Giken LSD. What have you heard that says otherwise?

You could have one built. Not cheap. What happened to yours?

pbonsalb wrote

You could have one built. Not cheap. What happened to yours?

Yeah, this...what the heck happened to your OEM diff?

Diffs on line; gear it down baby!

bought the car used and the diff was leaking. had the seals replaced right away but the gears grinded down. we think its because of fluid starvation

Redd wrote

There's nothing bad about an OS Giken LSD. What have you heard that says otherwise?

OS Giken Limited Slip Differential Failure - Why you shouldn't do business with OSG

idk.lol

I believe Giken has fixed their quality issue. No failures have been reported in recent years. Lots of great reviews here and in other forums. I have one and it really transforms the rear end of the car. It is still a clutch type so may make some noises, but so far zero chattering or grinding with OS250R fluid.

Since your gears are destroyed, I'd also do a shorter final drive at the same time.

Jerezblack.m3 wrote

bought the car used and the diff was leaking. had the seals replaced right away but the gears grinded down. we think its because of fluid starvation

Shit! Mine is leaking too. I have not driven it too much since I discovered, maybe 300 miles or so. But I don't know how many miles I've driven between leakage starting and discovering.

I'll be replacing the seal next week, just waiting it to arrive. But this thread scared me.

The smart thing would have been to check the diff fluid level and add fluid. A little seepage is not a big deal but a drip drip can be. How oily is the underside of the diff and surrounding area where a drip would get blown onto? Do you have drip stains on your garage floor or driveway?

The pictures are in thread below:

https://www.m3post.com/forums/showthread.php?t=1685044

Doesn't seem like drip drip, but the diff is oily.

There is a light drip stain in garage floor.

I'm not at home now. If I was, I would post new pictures.

The problem is that here in Brazil it's difficult to find the Castrol diff fluid, the only one available is the Motul 75W140, and I didn't want to mix. But obviously it would be better to have a mixed fluid, than not having any.

I don’t think you must use bmw fluid. Any 75W140 will work but if it does not have friction modifier for an LSD you will have to buy that separately and add it. Look for a gear oil with friction modifier, pull the upper plug and pump more in until it starts trickling back out through the hole. Or drain, unbolt the axles from the diff stubs, swing them out of the way but don’t let them hang on their own. Tie them up. Extreme angles are bad for cv joints. You may have to remove the exhaust to get access. Then pop out the stubs are remove the collars and replace the seals. Then refill the diff.

You should be replacing the fluid maybe every 60k miles. I did mine about 40k ago but it’s been about 5 years so I will do it again soon. Same with trans fluid and PS fluid. Brake fluid should be done about every 2 years or 30k.

pbonsalb wrote

I don’t think you must use bmw fluid. Any 75W140 will work but if it does not have friction modifier for an LSD you will have to buy that separately and add it. Look for a gear oil with friction modifier, pull the upper plug and pump more in until it starts trickling back out through the hole. Or drain, unbolt the axles from the diff stubs, swing them out of the way but don’t let them hang on their own. Tie them up. Extreme angles are bad for cv joints. You may have to remove the exhaust to get access. Then pop out the stubs are remove the collars and replace the seals. Then refill the diff.

You should be replacing the fluid maybe every 60k miles. I did mine about 40k ago but it’s been about 5 years so I will do it again soon. Same with trans fluid and PS fluid. Brake fluid should be done about every 2 years or 30k.

I suppose mine doesn't have fricction modifier, because the MY is 2008, and with 40k mls, I think the diff fluid has never been changed (I'm fourth owner), so the fluid would be that one that didn't come with FM. And the diff makes the grinding noises at sharp turns, which doesn't bother me at all.

But yes, I'm willing to use the Motul fluid, just didn't change it all yet because the seal hasn't arrived.

this is what we have to gamble when buying used cars. we dont know what the previous owner did. i tried saving it but it was too late.

Jerezblack.m3 wrote

this is what we have to gamble when buying used cars. we dont know what the previous owner did. i tried saving it but it was too late.

You guess how many miles it was leaking?

Could you please see my thread and say if it looks like your diff leakage?

https://www.m3post.com/forums/showthread.php?t=1685044

jvictormp wrote

You guess how many miles it was leaking?

Could you please see my thread and say if it looks like your diff leakage?

https://www.m3post.com/forums/showthread.php?t=1685044

That looks bad. Have you tried adding fluid to it? Iirc, my tech added 2 quarts when he filled the diff the very first day i got it. Then later i decided to reseal the sides and the front

So I should be prepared to have bad news when I remove the input leaking seal.

You can see the gears by the input, right?

Jerezblack.m3 wrote

bought the car used and the diff was leaking. had the seals replaced right away but the gears grinded down. we think its because of fluid starvation

I hope that shop is paying for this. They're the ones that ruined it. It was no fluid starvation, it was caused by an incompetent tech.