[Prev][Next][Index][Thread]

Re: Clunky shifts in '88 635 Auto

Roy asks..

>I've finally fully inherited my mother's '88 635CSi with the auto box, 
>bless her heart.  However, after living with it for a week now, I've 
>noticed something odd and I wonder if that is normal or should I have it 
>checked out.  I've noticed that the car, especially under part (ie. 1/4 
>to 1/2) throttle acceleration, the shifts from 1-2 and 2-3 are rather 
>clunky, sounds like the transmission is about to fall out of the car.  
>The problem is especially pronounced when the car is cold, which is 
>probably attributed to cold transmission fluid.  Is this normal?  Has 
>other 635 or 535 owners with the auto box noticed this phenomena?  I 
>don't really want to ask the dealer to check it only to pay $100 to find 
>out that it's normal.  Thanks for any information.

Well - it ain't normal, but it is somewhat common. The cause (which prompted
BMW to replace BOHICA's tranny under extended warranty) is gunked up electronic
solenoids in the tranny (your tranny is electronically controlled) - usually
caused by ?? (maybe infrequent fluid changes).

The cures are:

1. Ignore it. It won't get better - but when the tranny finally fails it
will be fixed by the new one.

2. Fix it. Replace tranny (big $$$), or - have a reliable trans shop drop
the tranny valve body and replace all the seals and clean all the solenoids.

3. Try to make it better. Try changing the trans fluid several times. Since you
can only change about 1/2 of the fluid (the rest is captured in the torque
converter), several times is better than once. On the last change, also drop
the pan and change the filter and gasket.  This *MAY* help. Transmission fluid
DOES WEAR OUT! It relies on a change of state (from lubricant to non-lubricant)
for the clutches to work. Eventually the shearing action in the tranny breaks
down the fluid - and it doesn't work like it should.  New fluid MAY help.

Luck.. and let us know how it works out!

========================================
Don Eilenberger ([email protected]
========================================
 '79 R65 FrankenCycle     - der Beemer
 '87 535i BOHICA          - der Bimmer
 '75 Hunter 25 WindBreaker  - das Boot
========================================
DOD#1177, BMW-CCA#104316, BMW-MOA#64000
NJS-BMW-R#0001 (I'm a glutton for clubs)
========================================
  "He who dies with the most toys, 
  probably leaves them to someone who 
  just doesn't know how to take care of
  them".... ANON..
========================================
  "Only difference between a man and
   a boy is the price of the toys!"
========================================