Does anyone have a rear case for a E36 differential, its for 3:91 if it makes a difference? (Note: The rear case has the two bolts for the bushings at the top and has six smaller bolts that bolt the differential.)

Matt?

That's the rear cover.

Mike McCoy might have one, sorry I don't.

That's the rear cover.

Mike McCoy might have one, sorry I don't.

I was just talking to Mike a little while ago, he didn't mention he had one. He did recommend replacing the rear cover.

Thanks though.

just to show the magnitude of this problem.
Here is the link.
http://forums.bimmerforums.com/forum/showthread.php?t=748471&highlight=differential

So I was changing my oil for my differential, when I went to tighten the drain plug again the gasket (washer for plug) cracked with the cover. This was was bound to happen since there was damage around that area before from something hitting or scraping against the cover by the drain plug.

Now the question is what is the easiest way I can repair this? Weld? JB Weld? or replace the differential cover?

Which method would be most reliable along with ease. I really want to weld since it would be easy and I don't have to go through the hassle of removing the sway bar and the cover.

http://img249.imageshack.us/img249/9203/1008497qp4.th.jpg (http://img249.imageshack.us/my.php?image=1008497qp4.jpg)

http://img296.imageshack.us/img296/5820/1008499fl8.th.jpg (http://img296.imageshack.us/my.php?image=1008499fl8.jpg)

http://img241.imageshack.us/img241/425/1008496nx0.th.jpg (http://img241.imageshack.us/my.php?image=1008496nx0.jpg)
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Update: I applied some JB Weld and will try to put some oil in there tomorrow. If that fails, then plan B is for a new cover and gasket.

That's not a very big problem... :dunno

You can't weld that in the car, or with it attached to the diff. And if you're taking it off the diff you might as well just replace it instead of welding it which might warp it. It's not that hard to swap covers and Mike is giving you a good deal. (I told you he had one. :stickoutt)

JB weld will work for a while, but eventually will let go and then you might be buying a whole new diff. Just swap the cover. Gaskets are about $5 at a dealership or RTV will seal fine.

That's not a very big problem... :dunno

You can't weld that in the car, or with it attached to the diff. And if you're taking it off the diff you might as well just replace it instead of welding it which might warp it. It's not that hard to swap covers and Mike is giving you a good deal. (I told you he had one. :stickoutt)

JB weld will work for a while, but eventually will let go and then you might be buying a whole new diff. Just swap the cover. Gaskets are about $5 at a dealership or RTV will seal fine.

Yes, you are right. Replacing the cover is Plan B, if Plan A fails (JB Weld). The thing is I can buy the cover from Mike or Bobby but the gasket would take longer to arrive. Bret didn't have have one and United said it would take two days, if ordered on Monday then it would arrive Wednesday.

I figured if I'm going to have the car in the air for two days why not mess with JB Weld and see how that goes. Right now it's going to cure for 15 hours and I will see tomorrow if it leaks. I have nothing to lose anyways since I can buy a used cover anyways.


Thanks for you input.
Matt, do you just hate it when you start a project and it turns out taking 3x time then it would initially? I know you know what I'm talking about. :shifty

I hate it, but it happens. It's never happened to me on a project shorter than a motorswap though. :dunno I can take out a diff, swap and reseal covers and have it back in in an easy afternoon. (say 2PM to 6PM)

You don't really need the gasket. My diff cover is sealed with RTV only and it's holding up fine.

An lastly, JB weld is a shitty "plan A." It will work right now, but it will probably fail later on.

I hate it, but it happens. It's never happened to me on a project shorter than a motorswap though. :dunno I can take out a diff, swap and reseal covers and have it back in in an easy afternoon. (say 2PM to 6PM)

You don't really need the gasket. My diff cover is sealed with RTV only and it's holding up fine.

An lastly, JB weld is a shitty "plan A." It will work right now, but it will probably fail later on.

:lol
Well this only a temporary fix. I will see when it will start to leak, by then I will probably have everything ready to install. I just hate having my car on jack stands for a long period of time ( more than a couple days) it worries and depresses me :(.

If i was to RTV it, would I have to smother it with RTV on the diff and the cover?
It should work, it's pretty small crack. I have covered it with JB Weld everywhere on the bottom of the drain plug.

I hate it, but it happens. It's never happened to me on a project shorter than a motorswap though. :dunno I can take out a diff, swap and reseal covers and have it back in in an easy afternoon. (say 2PM to 6PM)

You don't really need the gasket. My diff cover is sealed with RTV only and it's holding up fine.

An lastly, JB weld is a shitty "plan A." It will work right now, but it will probably fail later on.

:lol
Well this only a temporary fix. I will see when it will start to leak, by then I will probably have everything ready to install. I just hate having my car on jack stands for a long period of time ( more than a couple days) it worries and depresses me :(.

It should work, it's pretty small crack. I have covered it with JB Weld everywhere on the bottom of the drain plug.

If I was to RTV it, would I have to load it with RTV on the diff and the cover then leave it for a couple hours?

I hate it, but it happens. It's never happened to me on a project shorter than a motorswap though. :dunno I can take out a diff, swap and reseal covers and have it back in in an easy afternoon. (say 2PM to 6PM)

You don't really need the gasket. My diff cover is sealed with RTV only and it's holding up fine.

An lastly, JB weld is a shitty "plan A." It will work right now, but it will probably fail later on.

That is your e30 though. It took me a good 7 hours to swap diffs and covers the first time around. Do you need to drop the exhaust and swaybar to fully get to yours? E36 owners do. Also, it didn't help having a jack with a 1" plate to balance the diff on either. It wasn't that hard, it's just that with a jack like that, it can wear you out quickly and leave you sore for a day.

As for that crack, does it go through all the threads? If not, it may actually hold. JB Weld is not that great, but it should handle it. I wouldn't sit on it if it does though. And yes, I did not use the gasket either. It's just a paper one. If you want it, I have a new one that I did not use. I do recommend just grabbing some black RTV and making a nice bead around the gasket area and squishing to that area. Make sure you follow the directions though, because some may need 15 minutes of air to create that seal you want. Other than that, just be careful and buy yourself a torque wrench, even if it is a cheapo 20-30 dollar one at Autozone. It's better than guessing.

That is your e30 though. It took me a good 7 hours to swap diffs and covers the first time around. Do you need to drop the exhaust and swaybar to fully get to yours? E36 owners do. Also, it didn't help having a jack with a 1" plate to balance the diff on either. It wasn't that hard, it's just that with a jack like that, it can wear you out quickly and leave you sore for a day.

As for that crack, does it go through all the threads? If not, it may actually hold. JB Weld is not that great, but it should handle it. I wouldn't sit on it if it does though. And yes, I did not use the gasket either. It's just a paper one. If you want it, I have a new one that I did not use. I do recommend just grabbing some black RTV and making a nice bead around the gasket area and squishing to that area. Make sure you follow the directions though, because some may need 15 minutes of air to create that seal you want. Other than that, just be careful and buy yourself a torque wrench, even if it is a cheapo 20-30 dollar one at Autozone. It's close enough.
Thanks for the response Rob. I just have to drop the swap bar to swap covers, correct? Not the exhaust, I don't think so.

I will let you know if I need the gasket, probably not since you are the fourth person today that has told me the gasket isn't needed and RTV should do fine.

Thanks for the response Rob. I just have to drop the swap bar to swap covers, correct? Not the exhaust, I don't think so.

I will let you know if I need the gasket, probably not since you are the fourth person today that has told me the gasket isn't needed and RTV should do fine.

The swaybar is a must. You could probably get it done with it still on there, but it's not fun. If you are just taking the cover off, you won't need to mess with the exhaust. Removing the catback helps with getting to the axle torx bolts when removing the diff. You shouldn't have a problem with removing the cover, just make sure you have it supported by a jack and to catch as much as you can of that diff fluid. I dropped a nice little puddle swapping mine out, and the garage still reeks of the awful smell.

I didn't need to remove anything else to get my diff swapped. Exhaust and swaybar were both in place.

I haven't really worked on any e36s so i'm not sure what all needs to move.

Yes it is much easier to remove the exhaust and remove one end of the sway bars. But really focusing on doing a diff swap, and not getting drunk before hand. I can do the swap in about 3 hours.

BTW I might have a diff cover for you after saturday.

JB Weld cracked along the same line of the original crack on the cover. :mad
Waste of time and energy on the JB Weld. :shifty and :mad

JB Weld cracked along the same line of the original crack on the cover. :mad
Waste of time and energy on the JB Weld. :shifty and :mad

Was this really a surprise? :dunno

Was this really a surprise? :dunno

half and half. :(

AutoFAB might have a cover, and anything else you need, and they can do any welding if needed. they have tons of diffs lying around from e30's and e36's.

678-482-2221
Ask for Thomas.

I have a 3:91 collecting dust behind my shed...the only thing is it's heavy as hell so shipping is $$, but you are welcome to it.

So what did you end up doing?

I can tell you as of 1 hour ago pull-a-part in S. ATL has a rear cover already off and sitting in the trunk. I happened to notice it when I was looking around earlier. It looks to be in excellent shape.
The e36 in question has the roof sawed off and it's black. It's the only e36 in there, if that helps.

So what did you end up doing?

I tried the JB Weld on Monday and let it dry for a day. I tried plugging in the plug back on tuesday afternoon and added fluid in there. It started leaking in there and the JB cracked along the same line of the original crack on the cover. The crack was in the threads and inside the cover. I don't know why the cover is a soft aluminum, can someone chime on that?

I picked up a cover from Mike on Wednesday (after a second try I had one, Mike :)). I took off the old cover the same day with a long 3/8 extension and a Universal U-Joint for the very top two bolts. I cleaned up the old gasket on the cover and the differential with lacquer thinner and a blade. On Thursday afternoon I bolted the cover back on with some BG Black RTV (supplied from Mike). I hand torqued the bolts with the "feel." I put the cover back on at around 3 PM and let it dry for 22 hours just to be safe since on the back it said "cured in 24 HR."

Today around at 1 PM I pumped Mobil 1 75W-90 and torqued back the fill plug. I picked up my brother and sister from school (2 Mi) and drove back, I didn't notice any leaks. I just took another test drive after that around 5 PM (16 MI) and I didn't notice any leaks.

Special and Big Thank You to Mike McCoy (Techno550) :thanks:
for putting up with my calls and giving advice. Thanks for everything man.

Also Thank You to Bret, Robstah, Matt, and Karl. Thank you guys.

Glad to hear you're back on the road. I used the same stuff on mine, it's fine. It was actually fine after about a half hour. Good stuff.

The cover is soft so that it breaks ($90 brand new) rather than tearing its mounts out of the chassis ($$$$$$ in labor to fix).

Glad to hear you're back on the road. I used the same stuff on mine, it's fine. It was actually fine after about a half hour. Good stuff.

The cover is soft so that it breaks ($90 brand new) rather than tearing its mounts out of the chassis ($$$$$$ in labor to fix).

why is it so soft though and the differential is steel?

Rear cover isn't *that* soft. its just aluminum. and its aluminum so it moves heat through it quickly/easily. the rear cover is most of the cooling of the diff fluid.

Rear cover isn't *that* soft. its just aluminum. and its aluminum so it moves heat through it quickly/easily. the rear cover is most of the cooling of the diff fluid.

thats what I thought at first and that was the only explanation I could come with it. Thanks for the clarification.