Manual trans main shaft bearing

[16valex]

I don't know if I use the correct terminology, but took a look under my 97 528I the other day and it seems that there's some gear oil started to siping out from the rear of the manual trans where the drive shaft meet

How pain of a job is it and do I have to drop the tranny? Thank you all for your inputs.

Alex

[cnn]

Originally Posted by 16valex

I don't know if I use the correct terminology, but took a look under my 97 528I the other day and it seems that there's some gear oil started to siping out from the rear of the manual trans where the drive shaft meet

How pain of a job is it and do I have to drop the tranny? Thank you all for your inputs.

Alex

Hi,

The fact that your man trans leaks tells me you probably have at least 140-150K miles. All the terminology you need to know is here:

http://www.zf-group.com/pdf/S531.pdf

- The FRONT bearing is where the main INPUT shaft is.
- The REAR bearing is where the OUT shaft is.

** With trans IN the car, the ONLY seal that can be changed is the REAR seal.

BEST: When doing Clutch job, ALWAYS change ALL the seals in the man trans:
- FRONT seal
- REAR seal
- SELECTOR Fork seal.

cn
98 528i 5sp 92K

[Eric S.]

Originally Posted by 16valex

I don't know if I use the correct terminology, but took a look under my 97 528I the other day and it seems that there's some gear oil started to siping out from the rear of the manual trans where the drive shaft meet

How pain of a job is it and do I have to drop the tranny? Thank you all for your inputs.

Alex

I once changed the rear shaft seal on a 1985 Z-28 I owned (Borg-Warner T5 transmission). It wasn't too hard:
1) drain tranny oil
2) disconnect drive shaft at rear differential u-joint.
3) remove drive shaft, sliding it toward the rear (watch for oil pouring onto your face from the rear of the trans when you pull the driveshaft splines out)
4) remove old tranny seal ("rent" a slide hammer from Autozone to make it easy, altho I know I didn't use on ewhen I did my camaro's seal).
5) carefully align new seal and, using a suitably-sized old impact socket or similar (whatever equally pushes the new seal in all the way around its perimeter), gently hammer the new seal into place.
6) re-install drive shaft and refill tranny.

That's pretty much your basic schematic for the job. I urge you to get specifics from a manual for your particular car. I don't think you need to worry about replacing your other tranny seals if this is the only one leaking AND you can replace it using the same basic procedure as outlined above.

I agree with CN that you ought to do all the other seals if you are replacing your clutch anyway, but I wouldn't launch a clutch replacement job just because of this leak.

Good luck to you!

[16valex]

CNN, you hit it right on the head man, my car has about 141K miles and still runs great. I realy love the pre-VANOS BMW erra, these engines are much more reliable then nowaday ones.

I guess I will have to wait untill I change the clutch at the same time this makes more sense.

Thanks Eric. Have you miss working on BMW yet

[cnn]

Originally Posted by 16valex

CNN, you hit it right on the head man, my car has about 141K miles and still runs great. I realy love the pre-VANOS BMW erra, these engines are much more reliable then nowaday ones.

I guess I will have to wait untill I change the clutch at the same time this makes more sense.

Thanks Eric. Have you miss working on BMW yet

1. Redline Gear Oil MT-90 is thick and should slow the leak.
Keep topping it up every three months. I wrote the tips and tricks for Man Trans + Rear Diff and posted it here:
REAR Diff & MANUAL Trans Fluid Change: Tips and Tricks

2. Do the clutch job becuase clutch rarely lasts more than 160K.
While you are there, consider also:
- Cluth Master/Slave cylinders as at that age they are dying slowly. Plus it saves on labor later.
- Man Trans Seals x 3.

cn

[16valex]

Awsome write-up there CNN. I wish you are my neighbor so you help me with the clutch

Alex

[Eric S.]

Originally Posted by 16valex

Thanks Eric. Have you miss working on BMW yet

Don't miss fixing my 540 at all - yet! I miss driving it though!

However, this weekend I successfully resolved the two big "issues" I had with my Maxima:
1) Excessive moonroof wind noise ($2 shims, 1/2-hour of work)
2) Loud rear-end noise (Replaced right rear wheel bearing/hub - $125 parts + 2 hours of my time).

Now all that's left is resolving what I'm going to do with my dead-display radio (keep/fix or go aftermarket). At least mechanically I think I'm there. This thing could use some bigger sway bars though...