Transmission

[Bismark]

MOST LIKELY CAUSE IS VALVE BODY. THE BORE OF THE PRESSURE REGULATOR VALVE GETS WORN, THIS CAUSES SOME DELAY AND A KICK WHEN COASTING ON AN UPSHIFT, SPECIFICALLY FROM 3RD TO 4TH. SOMETIMES OTHER HYDRAULIC CIRCUITS ARE AFFECTED AND SIMILAR SYMPTOMS OCCUR ON DOWNSHIFTS. TO TRULY FIX THIS PROBLEM YOU MUST REPLACE THE VALVE BODY OR FIX THE BORE AND REPLACE THE REGULATOR VALVE WITH A LARGER ONE. THE REPROGRAMMING SOLUTION IS A MASKING FIX. IT SOLVES THE PROBLEM BY INCREASING THE HYDRAULIC PRESSURE TO COMPENSATE FOR THE LOSS OF PRESSURE LEAK CAUSED BY THE ENLARGED BORE.

[JCL]

Originally Posted by X5Sport

This may, or may not, add to the debate but I have just had my transmission rebuilt after the torque converter failed (lock up sprag clutch sheared) and caused catastophic damage due to debris in the oil damaging various clutches downstream and ruining the oil pump to the extent that metal shavings from the pump wrecked the gearset for 1st to 3rd too. The rebuild shop is a ZF specialist and they want the car back after 6months/6,000 miles to do a complete fluid and filter change. The original failure occurred at 42k miles.

More worryingly - and I pass on on for that reason - was his comment that they are now seeing so may of the 6-speed auto failures (not just in BMWs) they now keep the spares on site whereas they used to special order them. Most of the failures are actually being caused by electronics or electrically controlled hydraulic devices breaking rersulting in downstream failures when vales operate incorrectly or fail to operate at all - and not fluid related.

Thanks for posting. It is entirely anecdotal, but it is also consistent with the types of failures that have been reported on this site over the past four years or so.

[JCL]

Originally Posted by Bismark

Most likely cause is valve body....

I'm sorry, but I'm not sure which transmission issue you are referring to here.

[DrunkenNinja]

I had this fixed today...

OLD EGS and ECU Module flashed with an OLDER version then a drain and refill of the Trasmission fluid and a new Transmission filter...

Total cost was around 400 Euro (The fluid is expensive) Plus evrrything is double the price here in Cyprus...

Anyway the problem has completely gone...