Scraping from the trans?

jmissiaen · 11-28-2005, 07:11 PM

Hello,

I currently own an amazing 1985 bmw 325e
I bought it this summer for 800 bucks and have
been driving it every day and hasnt given my any problems of note.
After I got it I was driving it and noticed that once in a while there was this strange scraping noise that sounds like metal on concrete. It only happend at low speeds and not very often so I didnt think much of it.
Well, on friday I replaced the clutch (not too bad of a job on this car) and now everytime I drive between 15 and 45 mph I hear the scraping sound. It's not at all when I am sitting still...and it wont start usually until I hit a bump in the road...but sometimes it starts right away. It usually happens on bumpier roads but will sometimes just randomly start on a perfectly smoothe road too. It dose not change with faster RPMs or with faster speed but usually goes away at 45 mph
once in a great while you will hear it for a second when you are on the highway. It stops everytime I stop the car too but starts again when I hit the first bump. It sounds like it's coming from around the transmission area but dosent really sound like it's from in the trans.
If anyone has heard about this or has any pointers at all that would be great because this is getting really annoying and embarrasing.
THanks

Jmissiaen

coolbear1 · 12-02-2005, 05:01 PM

I have a retired 85 e30, one easy thing to check is the exhaust mounts. They will cause the car to make lots of strange noises. The other not so easy is the drive shaft couplings.

Also, has the tire/wheel arrangement has been altered? If so the wheels may be scrubbing.

By the way, the car you have is almost indestructable.
Unless you have an 18 year old.

jmissiaen · 12-02-2005, 06:13 PM

Thanks,
I'll check that stuff out.
I have to replace the motor mounts and trans mounts tomorrow so maybe I can get a chance to check the other stuff out.
I try to take care of this car as much as possable and today I just replaced the thermostat (it just happend to stop working the coldest day we had so far)
By the way, I'm an 18 year old

coolbear1 · 12-02-2005, 08:25 PM

Sorry, my bad, for the 18 crack.
I had a good reason for it, but not at your expense.
I bought a 1985 325e new for my wife the same year my daughter was born.
My wife drove it for about 15 years and even though it had 400,000 miles, it was still in such good shape.
So I thought it would be neat to put it up for my daughter's first car, since it was the only car she had ever really known.
She turned 18 and promptly ran into the back of someone and totaled it.
Thank god no one was hurt.
I found her a 88 325i convertable.
She didn't like it.
I still have it. It's for sale.
Now she has a 98 Z-3 roadster.
We pray allot.
But she likes the car and she's really a good young lady and deserves it.

jmissiaen · 12-03-2005, 01:09 PM

personally I would have stuck with th e30 (but thats just me)
I didnt get a chance to look at it today because it was busy at work...but hopefully this week.
Do you think it could be the bearing in the drive shaft support? Just a thought.
THanks

coolbear1 · 12-04-2005, 03:00 PM

Yea me too, I like the e30, it has classic looks that just don't go out of style.

The drive shaft on your car could very well be the culpret.
How many miles do you have?
I think I put a rebuilt drive shaft in my 85 at about 185,000 miles, due to constant vibration, not much noise.
I have also replace several wheel bearings, now that can be a real job,
they are press fit and hard as hell to get out sometimes. I doubt that is your problem though because they just make a rumbling sound at all speeds.
When you hammer down on it, does it also cause the noise?

jmissiaen · 12-09-2005, 11:47 AM

I found out where the noise is coming from...
The center support bearing on the drive shaft, must have some loose balls or just needs a repack of grease...never messed with it on an e30 so I have no idea...I might try and fix it...or live with it...

coolbear1 · 12-09-2005, 07:25 PM

Just out of curiosity I looked up the invoice where I repaired the driveshaft on my 85 e30.

I purchased a rear drive shaft with u-joints, also flex couplings, and center bearing. The date was june of 1991 and the car actually had 316,226 miles at the time.

I noted that the u-joints had play.

I don't let anyone else work on my cars, but I also don't remember doing the work, so it must have been fairly easy, I always remember the tough jobs. If you end up having to do it I can give you the procedures out of my Bently manual.