[jpsanfor]

I have a 2008 6MT 335XI and I found fluid leaking from the pinion in the rear end when I was changing the brakes. I checked the fluid level and it is just below the fill/inspection hole in the rear cover. I just checked it again after a few weeks and no significant change to the fluid level. However, I still want to change the pinion seal.

My car has this style of driveshaft with the insert nut (12):

https://www.realoem.com/bmw/enUS/sho...diagId=26_0233

I don't foresee an issue removing the insert nut but I see an issue with finding a tool to remove the pinion nut (shown between 8 and 9):

https://www.realoem.com/bmw/enUS/sho...diagId=33_1403

Does anyone know if this fits a basic, albeit large, 12 point socket or is the only option to buy the special tool?

https://www.ecstuning.com/b-genuine-...n/83300495552/

And as far as holding the pinion there is a special tool to use in conjunction with the 12 pt ring/socket but I was just going to use the ground...

[feuer]

I have couple of wrenches for diff removal and new nut left over. I will post photos tomorrow.

[feuer]

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[jpsanfor]

That is the insert nut and wrench correct? I don't have a problem with that, it's a 50mm thin wrench. My problem is the 12 point nut that sets the pinion shaft preload. I don't know if it's a standard size I can get or if I'll be forced to but the special (expensive) tool...

[mweisdorfer]

Originally Posted by jpsanfor

That is the insert nut and wrench correct? I don't have a problem with that, it's a 50mm thin wrench. My problem is the 12 point nut that sets the pinion shaft preload. I don't know if it's a standard size I can get or if I'll be forced to but the special (expensive) tool...

I have seen them for $50-60.00 and as inexpensive as $29.99 on Amazon. On Amazon, you'd search for an ATV axel wrench. HP Autoworks sells 50mm wrench for $65.00. I have this one. Nice wrench....

https://www.hpashop.com/HPA-Differen...4diff-tool.htm

If you want to save a few dollars, I'm sure the ATV axel wrench will work. Just make sure it's 50mm.

[jpsanfor]

Originally Posted by mweisdorfer

I have seen them for $50-60.00 and as inexpensive as $29.99 on Amazon. On Amazon, you'd search for an ATV axel wrench. HP Autoworks sells 50mm wrench for $65.00. I have this one. Nice wrench....

https://www.hpashop.com/HPA-Differen...4diff-tool.htm

If you want to save a few dollars, I'm sure the ATV axel wrench will work. Just make sure it's 50mm.

I guess I'm not being clear... the 50mm wrench is for the insert nut which holds the driveshaft on the pinion shaft. Everyone and their brother has that already for doing the LSD swap or removing the driveshaft.

I am wondering if this (the flange nut) is a standard socket size:

https://www.amazon.com/BMW-Differential-Flange-Nut-Wrench/dp/B01F4G2KG6

Or do I need to get my wallet out? Note this in not used for the LSD swap or removing the driveshaft, that's the 50mm wrench for the insert nut. I want the socket for the flange nut, there are 2 nuts on the input to the diff...

[mweisdorfer]

Originally Posted by jpsanfor

I guess I'm not being clear... the 50mm wrench is for the insert nut which holds the driveshaft on the pinion shaft. Everyone and their brother has that already for doing the LSD swap or removing the driveshaft.

I am wondering if this (the flange nut) is a standard socket size:

https://www.amazon.com/BMW-Differential-Flange-Nut-Wrench/dp/B01F4G2KG6

Or do I need to get my wallet out? Note this in not used for the LSD swap or removing the driveshaft, that's the 50mm wrench for the insert nut. I want the socket for the flange nut, there are 2 nuts on the input to the diff...

The flange nut this holds the drive shaft to the Diff is 50mm. You will need one of two wrenches to get it off, and you should replace it once you take it off. You will need a torque wrench to put the new one back on to spec

[Koolsilver]

Are you able to show a picture of the nut you are trying to get off? I can't think of anything particularly odd on the differential besides the 50mm that everyone has already mentioned.

Edit: I just saw the other thread you bumped up and saw the pictures. That's definitely an odd one I'm not sure of that size hopefully someone else can help you with that.

[jpsanfor]

Originally Posted by Koolsilver

Are you able to show a picture of the nut you are trying to get off? I can't think of anything particularly odd on the differential besides the 50mm that everyone has already mentioned.

Edit: I just saw the other thread you bumped up and saw the pictures. That's definitely an odd one I'm not sure of that size hopefully someone else can help you with that.

Thanks for the reply, in the attached the nut in question is shown between 8 and 9:

https://www.realoem.com/bmw/enUS/showparts?id=VD53-USA-04-2008-E90-BMW-335xi&diagId=33_1403

(8) is the 50mm insert nut, not the flange nut I need to remove. The other thread I posted in says it's 64mm but based on the picture in that thread with the caliper showing the corner to corner (instead of flat to flat as nuts are measure) I'm skeptical of that being the correct size.

I can get a kit for about $300 with all the necessary tools or just the wrench for about $160. I'd rather just get a socket for 30ish since I hope to only use it once. The other issue is it's my daily driver so I don't have it up in the air and ready to take apart or I would measure it myself...

[collinja]

I'm curious if you ever did this repair. In my research it appears the nut you were looking for info on is 65mm. I'd also be interested is you had a step by step procedure to replacement of the pinion seal. Appears to me it is a matter of dropping the exhaust, removing the drive shaft, the 65 mm nut and then replacing the seal. Any insight on re-installing and torque specs?

Thanks!

[Schneelleopard]

There's a more comprehensive post here on this. https://www.e90post.com/forums/showt...4#post31302864

Wanted to place an update here. Since this thread was created several aftermarket alternatives to the BMW tool have become available through Amazon and ebay. They look like the image attached. Searching for BMW e90 differential pinion tool will turn up results in the $100 cost category.

I have completed this repair on my 2007 335i with the tool and I wanted to add some information for those who may read this thread in the future.

Both nuts are red locktite secured. To remove them you will need to heat them up very hot with a heat gun. Grease will shoot out of the seal so wear eye protection.

You will need a cheater bar for leverage. A 1 inch black iron pipe from home depot works well.

The first nut is turned CLOCKWISE that's counter intuitive yes I know. According to TIS failure to do so will destroy the Differential!

After removal, pry off the grease seal and grease cap using a cold chisel and a hammer. These parts must be replaced. You cannot do this job unless you purchase the grease seal, grease cap and suggested nut in addition to the differential pinion seal. I bought a kit made by Febest? it was very inexpensive. Available on Amazon for $30. Pinion Oil Seal Rear Differential Kit Febest SET-008 Oem 31507609535


After that you will be faced with the large funny looking nut with all the splines. It has to go back the same way it came off according to TIS. Take a steel pin punch and strike it hard with a hammer one hard time. This will put a small notch where the big funny nut and the pinion spindle meet. This will allow you to put it back the same way it came off.

you use two breaker bars to remove the large nut. One holds the shaft by the splines the other turns the big nut COUNTER CLOCKWISE. again. Before you start heat it up with a heat gun until oil starts to leak out and it stinks. You must use a cheater part to break it loose. Don't give up.

Clockwise and Counter Clockwise is as if you were facing away from the engine.

After you remove that large nut clean all the splines off that have the old locktite in there. remove all grease residue with a pick tool and a wire brush from everything.

Now you have to remove that seal. That seal is in there VERY tight. You may sacrifice a typical seal puller in removing it. There are alternatives. What I did was used a small pry bar and Karate Kicked it. The dynamic force popped it out. This method will do some damage the cast iron housing. I repaired it with coarse sandpaper and used some RTV silicone on the new seal lip, a very light coat.

More professional ways to remove this seal involve drilling pilot holes around the seal, and driving in sheet metal screws. Or even hardened wood screws which will push the seal out. Any marks will not be on the sealing surface this way. However, you may drive the screws into the bearing so it may be more prudent to drive in those screws 1/4 of an inch and pull the seal out using a basic bondo slide hammer. You could also use vice grips clamped onto the screws.

Yet another way is by using the N54 front main seal remover tool. The $50 ebay or amazon kit may allow you to remove the seal in the most professional of ways. I didn't try it.

I have not yet set the preload on the bearing. I will make a supplemental post after I do.

[Schneelleopard]

I added a post to help