Differential leak

[m3f_NolliM3]

The other day I was backing out of my parking spot and noticed that there was a slight thump on the passenger side as the wheel makes the revolution as if a bearing tooth were missing...so I investigated yesterday. I discovered I had a leak by the output seal on the passenger side so, I searched the forum then, jack up the car and turn the wheel while I placed the uncomfortable mechanic stethoscope to listen...couldn't hear anything. Then, I wondered whether it's uneven surface of the apartment parking lot.


Now, my research revealed some refill the differential with 75w90 and add the Corvette limited slip additive; however, when I check Pelican to source parts, all they had were the 75w140...is that the new acceptable fluid?


Also, I wanted to replace the seal without dropping the differential; however, this diagram suggests that there's a lock ring at the end...research results wasn't clear on whether I can pull out the drive flange after disconnection to change the seal. This will be my first time working on any differential...so any tips are welcome.





Differential from the passenger side





the underside of differential





The drip overnight

[m3f_englishtom1596q]

No problem doing it with the diff in. Undo the axle and move to one side. The flange pops out with a pry bar and looks just like the end of a regular CV joint. You can then pop the seal out and drive the new one in. Obviously you have to drain the fluid first or you'll have some spillage

[m3f_NolliM3]

No problem doing it with the diff in. Undo the axle and move to one side. The flange pops out with a pry bar and looks just like the end of a regular CV joint. You can then pop the seal out and drive the new one in. Obviously you have to drain the fluid first or you'll have some spillage

Thank you Tom for responding...I had also found this thread where you and Nick shared cool insights: http://www.m3forum.net/m3forum/showt...ferential+leak



Also, I found this YouTube video so I share here for others:

Differential Axle Seals DIY: BMW E36 3 Series (M3 Differential) - YouTube














I am surely glad that it's the passenger side; however, I shall do the drive side as well as change the input seal next month when I do the transmission overhaul. I must say I really appreciate BMW's clever design when I see how it all works.

[m3f_NolliM3]

Well, I was fired up to change out the differential seal and had gotten a 14mm socket allen wrench that Bentley recommended...then came the sadness...one cannot use the 14mm socket allen wrench because when one attaches the wrench, one discovers the wheel-well for the spare tire gets in the way. So, my dislike car emotions ran wild complaining that everything needs a special tool.


Then, I found Nick's thread and what he did...http://www.m3forum.net/m3forum/showthread.php?t=304962 I ordered a long regular 14mm allen wrench from Home Depot (their online) to ship to the store. However, what I am not clear about is whether it's the 1inch piece used because that would create the same scenario as the socket Allen wrench...wouldn't it!

[m3f_pbonsalb]

Cut a one inch piece off an Allen wrench or socket. Stick it in the drain or fill plug. Use a wrench on that. There are actually low profile Allen sockets made for this kind of work.

[m3f_JitteryJoe]

You trying to get the drain & fill plugs out?

There is a tool for this.

http://www.pelicanparts.com/cgi-bin/...%37%20mm%20Box

[m3f_Jrrrrrrr]

Another thing to try is to knock the 14mm hexagonal stub out of a cheap socket, then there will be plenty of room to use the stub with a box-end wrench. IIRC, when I ran into the clearance issue between the differential fill plug and the spare tire well, that's what I did. I used a cheap harbor freight allen socket and the stub came out way easier than you might think - so this is one case where poorly-made tools can come in handy.

[m3f_aeronaut]

Another thing to try is to knock the 14mm hexagonal stub out of a cheap socket, then there will be plenty of room to use the stub with a box-end wrench. IIRC, when I ran into the clearance issue between the differential fill plug and the spare tire well, that's what I did. I used a cheap harbor freight allen socket and the stub came out way easier than you might think - so this is one case where poorly-made tools can come in handy.

This.

[m3f_Double E]

$62.00 for the special tool ...my ass.

Drilled a hole in the spare tire well to access the fill plug...then foil tape to cover the hole back up

(on the race car).