Front differential pinion seal for 325ix? And other questions...

[Deja_Vu]

So I just bought a '91 325ix coupe last week and will be starting some much needed work on it. I decided to do it all myself after getting quoted over 4k to do it all. I've worked on cars before doing basic stuff like replacing the brakes, changing the oil, battery, etc. and helped my grandfather rebuild an engine on an old truck when I was 15 or so....but never tried doing something like this on my own however I am eager to learn. I am nervous about it all and am hoping you guys can guide me when I need help.

Anyways, the shop said the differential output seals need to be replaced so I decided why not do the inputs as well? I found the output seals (front and rear) for them but am not seeing the pinion seal (this is the same as the input diff seal, right??) for the front. Is there not one? I'm assuming there must be.

One other thing the service shop said needed to be replaced was the "M/T - Extension Housing: tail shaft seal." I'm trying to figure out what the hell that is. Maybe this output shaft seal?

Also, sorry if this is in the wrong sub-forum.

[TehRaydarlover]

http://www.realoem.com/

31521212516 would be your front differential input seal

You have to be careful doing the inputs, match mark the exact position of the flange nut. When reasembling you need to tighten the nut back to the same position (maybe just a hair tighter) If you tighten it too much you put too much preload on the pinion bearings and they'll run too hot, not enough and your pinion bearings will be sloppy and mess up the gear tooth wear. Watch some YouTube videos, or check out the differential rebuild link in my sig even. It's not to bad of a job.

[Deja_Vu]

http://www.realoem.com/

31521212516 would be your front differential input seal

Awesome, thanks. And this is the rear, correct?

You have to be careful doing the inputs, match mark the exact position of the flange nut. When reasembling you need to tighten the nut back to the same position (maybe just a hair tighter) If you tighten it too much you put too much preload on the pinion bearings and they'll run too hot, not enough and your pinion bearings will be sloppy and mess up the gear tooth wear. Watch some YouTube videos, or check out the differential rebuild link in my sig even. It's not to bad of a job.

Yeah I watched a few and saw you have to count the amount of rotations and all that when removing the flange. The process doesn't look too difficult or anything.

So what about my last question - any idea what the hell the "M/T - Extension Housing: tail shaft seal." is?

[TehRaydarlover]

Yep, its a different part number than what realoem shows but they are the same part. Yes, take a punch and stamp a dot on the nut and flange. Then just go back until the dot line up again.

Sounds like a trans output shaft seal or something. I normally ignore the part names and just go by the actual part numbers.

[Dave_G]

So what about my last question - any idea what the hell the "M/T - Extension Housing: tail shaft seal." is?

It's hard to say for sure, but maybe the shop saw the transfer case bolted to the back of the transmission, didn't know what they were looking at, and decided to call it a "M/T Extension Housing". If that's the case, then they're saying that the rear output seal on the transfer case is leaking. Also if that's the case, it doesn't inspire a lot of confidence in that shop.

[Deja_Vu]

It's hard to say for sure, but maybe the shop saw the transfer case bolted to the back of the transmission, didn't know what they were looking at, and decided to call it a "M/T Extension Housing". If that's the case, then they're saying that the rear output seal on the transfer case is leaking. Also if that's the case, it doesn't inspire a lot of confidence in that shop.

Ah. Well I'll check around there then for leaks. What's the best thing to use to clean up the oil on the covers without causing damage? Brake cleaner?

It was a BMW dealership's shop - don't know how much I can trust them as I've never dealt with them before. There was a highly rated BMW and Mini shop I was trying to get to do the PPI but they weren't available for 2 weeks.

[Deja_Vu]

Another question (not differential seal related at all). I bought the timing belt kit from Pelican and have all belts removed right now. A few questions:

a) How do you get the camshaft sprocket nut released without it spinning?

b) When should the thermostat housing be replaced? Just when it's cracked or something? Mine is looking scaly and has some buildup around the "threads" (really just ridges) for the hoses that's not coming up after scraping with a wire brush. I'm tempted to replace it just because it's looking rough. Is it worth it?

c) I also got a "gasket for front engine cover." This item. Doing a google search doesn't really show much of where it could go...and the same part number (minus M17) shows up as a timing cover gasket.

Hope you guys can help. I just wanna drive this thing!


Also, I double posted in 325iX as well but figured this was M20 related too. Sorry if it's against the rules. I just want help.