E32 750 transmission rough shifts

[Erlingur]

Hello BMW fans.
My name is Erlingur and I just bought my 3rd 7-er.

It is an 91 750 with 216.xxx km

I'm very happy with the car and the contition is extreamly good.
There are though two items that I need to fix.

I think that the ZF shifts way to roughly! It is like that the computer does not cut of the motor when the transmission is shifting gears. I would like to get this fixed for firmer driveing and to protect the ZF unit.

There is also an light vibration arround 40 km/h
The central supprot for the drive shaft is new and the tiers are OK any tips.

I'm sorry for not writing in German my skills are not that good yet.

[Erich]

Hello Erlingur

there is also a good English 7 Forum
 http://www.bimmerboard.com/forums/e32

think that the ZF shifts way to roughly! It is like that the computer does not cut of the motor when the transmission is shifting gears. I would like to get this fixed for firmer driveing and to protect the ZF unit.

Do you see the gear and mode indicated in the cluster?
If not, clean the gear selector switch which might be dirty
 http://www.nmia.com/~dgnrg/page_13.htm

Then always a transmission oil and transmission filter change is recommendable and often makes improvements in shifting.
How to do, is on my website below in the link to europeantransmissions.com

There is also an light vibration arround 40 km/h
The central supprot for the drive shaft is new and the tiers are OK any tips.

Where exactly is the vibration? In the area of the driveshaft, or in the front axle when driving, or while braking? Steering wheel?
This might help
 http://www.bimmerboard.com/forums/posts/293173/

[Erlingur]

Dear Eric,

thanks for extramly good and quick answer.

I'll look have to look over your advise later today.
The ZF is very quiet and I'would assume that the general condition of it is OK.
But I'll have to find out of this fault. I'm also planing on changeing the fluid and filter just to be shure that it is OK.

The vibration is arround the drive shaft. I just bought the car and it had a new center support on the dirveshaft (work made on an special BMW workshop) so I assume that the joints are OK.

[Erlingur]

Zitat von Erich

Do you see the gear and mode indicated in the cluster?
If not, clean the gear selector switch which might be dirty
 http://www.nmia.com/~dgnrg/page_13.htm

I do see the indicator in the cluster. But the selector needs a cleaning. There is some bad connection there. The D sometimes disapairs.
I have tried the S-E-M selector and it workes fine the engine revs up higher.

[Erich]

o.k., that problem is probably solved then after cleaning.
Here is another link for that from E34
 http://mysite.verizon.net/vzerdcib/e34a/id4.html

make sure the shop preloaded the center bearing 4~6mm towards the front of the car.
Also check the transmission mounts
 http://bmwe32.masscom.net/sean750/dr...terbearing.htm

[Erlingur]

Zitat von Erich

o.k., that problem is probably solved then after cleaning.
Here is another link for that from E34
 http://mysite.verizon.net/vzerdcib/e34a/id4.html

make sure the shop preloaded the center bearing 4~6mm towards the front of the car.
Also check the transmission mounts
 http://bmwe32.masscom.net/sean750/dr...terbearing.htm

The trans mounts could be worn. There is some knok noice when I accelerate/diaccelerate.

One thing that I'm thinking about regarding the ZF unit is:
Could the car have an performance chip?

[Erich]

I do not think that the tranny problem is from tuning chips, usually only the 2 chips in the MOTRONIC are changed and the one in the EML.
But nothing on the transmission module.

The trans mounts could be worn. There is some knok noice when I accelerate/diaccelerate.

Remove the heat shield below the drive shaft, then turn the rear wheel when you have lifted the car, the drive shaft will turn, and you can see marks where the drive shaft touched the tunnel above.
Either the center bearing is not pre-tensioned, not straight installed, or the tranny mounts are worn out.
I had the same problem about 2 years ago, a lot of noise under the car. In my case only the 2 bolts which hold the center bearing were lose and the center bearing was not in line.
The center bearing bracket has on each side slots (not holes) for these bolts.
 http://www.autohausaz.com/search/pro...port%20Bearing