[dbjb]

Hey all,

I'm close to pulling the trigger on a LSD. I have been attempting to determine which type of diff I currently have (bolted or welded). I've made contact with several different forum vendors including Wavetrac direct. Unfortunately, I've received 3 different answers ranging from 'definitely bolted' to 'definitely welded' to Wavetrac simply stating they'll have to get back to me.

Now, in researching many threads, it seems I have a build date that can go either way. My car is a 03/07 auto 335i. Some say I can use realoem.com and a VIN to figure it out. Some say the stamp on the drive unit dictates what I have. Since there is some much confusion, I figure the only way to truly determine what I have is to open her up.

Therefore I am wondering if anyone has the torque settings for the diff cover plate? Also, is there a gasket I need to replace? With the car on jacks, will I have adequate space to perform this task? Will I need to first remove the exhaust? Do I need to use Loctite? What else do I need to know?

Thoughts? Suggestions?

Thanks in advance.

[Bakeme521]

Yeah all the stats show before and after 03/07, not what was actually in it. So you're right the only way you will for sure know is to open it up. You should be able to do it on jack stands or on ramps in the rear. After installing mine I can say taking the exhaust off will make it much easier but it can be done with it installed. Since you are just doing the rear cover then you can probably get away with leaving the exhaust on. If you feel its becoming a PITA with it there then take it out. I'm sure there are torque specs for the rear cover, but if you can't find them, its a cast steel casing, just tighten it up pretty solid and put a little loctite on there. As for sealing there isn't a gasket there. Once you take it off, oil will come pouring out so be ready(there isn't a drain plug). Once you get it off you have to scrap the old gasket sealer off with a razor blade. When going to reinstall just apply some new gasket sealer Around the outside where the old stuff was(that tube of black silicone-like stuff, says "gasket maker" on the tube). After that you should be good to go and know the answer to your question.

[techlogik]

You don't have to open it up. Call Wavetrac, they can look it up by VIN.

If it is an auto between 03-09 2007, it is welded. Otherwise, it is bolted.

Manuals will vary also depending on when built.

Have no idea what tranny you have though, don't see if it is auto/manaul.

Again, they can look it up by the VIN. Get in touch with the LSD maker.

If it is welded, I would go with Wavetrac and they can build it with a spare core. $600+ for labor to do that they charge, but worth it instead of having your local shop rig/shim the thing with likely no experience doing a BMW diff swap like this one ever.

Of course, it will take you 4 months likely to get it, and it will cost $1600 +800 core charge, and another 2-3hrs labor to do the pumpkin swap by your local shop.

[stressdoc]

Originally Posted by techlogik

You don't have to open it up. Call Wavetrac, they can look it up by VIN.

If it is an auto between 03-09 2007, it is welded. Otherwise, it is bolted.

Manuals will vary also depending on when built.

Have no idea what tranny you have though, don't see if it is auto/manaul.

Again, they can look it up by the VIN. Get in touch with the LSD maker.

If it is welded, I would go with Wavetrac and they can build it with a spare core. $600+ for labor to do that they charge, but worth it instead of having your local shop rig/shim the thing with likely no experience doing a BMW diff swap like this one ever.

Of course, it will take you 4 months likely to get it, and it will cost $1600 +800 core charge, and another 2-3hrs labor to do the pumpkin swap by your local shop.

Good advice.

[Bimmer This]

I always thought that it's theother way around? 2007's are bolted as the rest are welded??????

[dbjb]

Originally Posted by techlogik

You don't have to open it up. Call Wavetrac, they can look it up by VIN.

If it is an auto between 03-09 2007, it is welded. Otherwise, it is bolted.

Manuals will vary also depending on when built.

Have no idea what tranny you have though, don't see if it is auto/manaul.

Again, they can look it up by the VIN. Get in touch with the LSD maker.

If it is welded, I would go with Wavetrac and they can build it with a spare core. $600+ for labor to do that they charge, but worth it instead of having your local shop rig/shim the thing with likely no experience doing a BMW diff swap like this one ever.

Of course, it will take you 4 months likely to get it, and it will cost $1600 +800 core charge, and another 2-3hrs labor to do the pumpkin swap by your local shop.

It's a 03/07 Auto. I did call Wavetrac. They weren't 100% positive either. Hence my post. Also, I don't think it's an absolute using the VIN or build date. Some forum members stated they've had BOLTED 08/07 builds which does not follow the general consensus of build date/type.

I think the better way to identify what I have is by the stamp on the final drive itself. Here it is below. Yet, I haven't been able to find someone that has the same part AND upgraded to LSD.

3311 7518413-01
685729-10
GERMANY
>EN AC-46000<
6805
2

[dbjb]

Originally Posted by Bakeme521

Yeah all the stats show before and after 03/07, not what was actually in it. So you're right the only way you will for sure know is to open it up. You should be able to do it on jack stands or on ramps in the rear. After installing mine I can say taking the exhaust off will make it much easier but it can be done with it installed. Since you are just doing the rear cover then you can probably get away with leaving the exhaust on. If you feel its becoming a PITA with it there then take it out. I'm sure there are torque specs for the rear cover, but if you can't find them, its a cast steel casing, just tighten it up pretty solid and put a little loctite on there. As for sealing there isn't a gasket there. Once you take it off, oil will come pouring out so be ready(there isn't a drain plug). Once you get it off you have to scrap the old gasket sealer off with a razor blade. When going to reinstall just apply some new gasket sealer Around the outside where the old stuff was(that tube of black silicone-like stuff, says "gasket maker" on the tube). After that you should be good to go and know the answer to your question.

I think this is the way to go. Now, a few more questions...

According to the link below, I can use Loctite 5970 to seal the cover. That should be easy enough. Now, should/could I reuse the gear oil? Should I buy new for now? If new, Motul or BMW oil? Lastly, how much will I need and what is the proper way to measure/fill?

BMWFANS link:
http://bmwfans.info/parts/catalog/E9...ve_gasket_set/

[Bakeme521]

Originally Posted by dsbj

I think this is the way to go. Now, a few more questions...

According to the link below, I can use Loctite 5970 to seal the cover. That should be easy enough. Now, should/could I reuse the gear oil? Should I buy new for now? If new, Motul or BMW oil? Lastly, how much will I need and what is the proper way to measure/fill?

BMWFANS link:
http://bmwfans.info/parts/catalog/E9...ve_gasket_set/

Seems a lot are disagreeing with this way, this truly is the only way to know completely FOR SURE. I wouldn't reuse it and you prob can't. I put the redline gear oil in mine and I put about 1.5 bottles in mine. And when you are filling it back up fill it up til it comes out of the fill hole and its full. make sure its not coming out anymore before putting the cap on. You should be able to stick your finger in the hole and feel the oil right there.

[dbjb]

Well, GREAT NEWS! It's BOLTED! Now time to order the LSD. In the meantime, I think I'll put together a basic DIY for those that'll need to check too.

Here's mine. Oh, those bolts are so pretty.

[turb0mik3]

Originally Posted by dsbj

Well, GREAT NEWS! It's BOLTED! Now time to order the LSD. In the meantime, I think I'll put together a basic DIY for those that'll need to check too.

Here's mine. Oh, those bolts are so pretty.

Sorry I didn't see this thread earlier, but all 335i auto LSDs are bolted.

[BerkTechnology]

Originally Posted by Mflowt5

Sorry I didn't see this thread earlier, but all 335i auto LSDs are bolted.

That was my understanding as well. There are different sized diffs and I've used 2 different auto 3.46 ratio "bolted" diffs. Each required completely different LSD's to swap in there.

PS - since you're mechanically inclined enough to pop off that cover I will give you my vote of confidence that you can do the carrier swap as well. As in swapping the pumpkin, not doing the actual differential install into the case. Save yourself the $200-500. You'll need the diff tool from AR Design and standard tools you probably already have. Go for it!!

[dbjb]

Originally Posted by Mflowt5

Sorry I didn't see this thread earlier, but all 335i auto LSDs are bolted.

Not according to Post 21 on this thread. (http://www.e90post.com/forums/showthread.php?t=321347) Trust me, if this was a black and white answer, I wouldn't have taken the time to remove my chassis brace, drop my exhaust, loosen my pumpkin from the subframe and pull my cover plate. At least, I can say it was satisfying doing it myself.

FYI, I think you may be welded. From what I can tell, Pre 03/07 was bolted, then they started to switch to welded.

[dbjb]

Originally Posted by BerkTechnology

That was my understanding as well. There are different sized diffs and I've used 2 different auto 3.46 ratio "bolted" diffs. Each required completely different LSD's to swap in there.

PS - since you're mechanically inclined enough to pop off that cover I will give you my vote of confidence that you can do the carrier swap as well. As in swapping the pumpkin, not doing the actual differential install into the case. Save yourself the $200-500. You'll need the diff tool from AR Design and standard tools you probably already have. Go for it!!

EDITED:

Thank you for the vote of confidence. I had a friend help too. It sure was nice having someone fetch tools while I was under the car... also removing/installing the exhaust.

After we popped the cover, we kept thinking the same thing. Maybe we should just get the AR tool and remove the pumpkin. I just don't know how to pop off the half shafts. Beyond that, I guess I would need some more gear oil, rtv, and replacement axle seals.

[BerkTechnology]

The half shafts are held in place with torx screws. The axle doesn't actually go into the diff like you're used to seeing on other cars. The torx screws you see are the only thing you touch. When your tranny shop installs the diff they will have to worry about pulling the stub axle out of the case.

[Bakeme521]

I am glad you got everything figured out, and by the way, I think the halfshafts were the easiest to get out. You will find out soon enough when you have to pull the whole pumpkin.

[Penn999]

http://www.hpashop.com/images/differ...%20options.jpg

[techlogik]

Originally Posted by dsbj

It's a 03/07 Auto. I did call Wavetrac. They weren't 100% positive either. Hence my post. Also, I don't think it's an absolute using the VIN or build date. Some forum members stated they've had BOLTED 08/07 builds which does not follow the general consensus of build date/type.

I think the better way to identify what I have is by the stamp on the final drive itself. Here it is below. Yet, I haven't been able to find someone that has the same part AND upgraded to LSD.

3311 7518413-01
685729-10
GERMANY
>EN AC-46000<
6805
2

Sorry, didn't check back on this thread. Wavetrac is full of crap. Ask Mike at N54tuning, we went through this with the group buy. All they ended up needing was the VIN to find out what we had.

All autos from 03-07/10-07 are welded. Otherwise, autos are bolted. I was told that directly from Mike who got that info from Wavetrac.

Now, this brings up the point, if you car is bolted, and it is indeed a 03-07 build, there might be some point in that month where they switched to welded for a short time and that is the case what I know.

But then again, Mike, Wavetrac and whoever else gave us this info might all be clueless and idiots, which wouldn't surprise me either.

Glad you got it sorted so you know what is the correct thing to order and need.

[techlogik]

Originally Posted by Mflowt5

Sorry I didn't see this thread earlier, but all 335i auto LSDs are bolted.

Not from what I was told. During our groupbuy from Wavetrac, and after using our VINs, Wavetrac stated that Autos from 03/07-10/07 were welded. Don't know the exact cutoff date.

Whether they lied, are wrong and stupid, I don't know...I got out of the group buy and don't care anymore.

[turb0mik3]

Originally Posted by techlogik

Not from what I was told. During our groupbuy from Wavetrac, and after using our VINs, Wavetrac stated that Autos from 03/07-10/07 were welded. Don't know the exact cutoff date.

Whether they lied, are wrong and stupid, I don't know...I got out of the group buy and don't care anymore.

Nope, all automatics are bolted. I work at HP and have gone through this many times, lol. Check the linky above.