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      02-28-2018, 09:32 AM   #196
mcastles
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Drives: BMW 328Xi
Join Date: Jul 2015
Location: CT

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Hi

I just wanted to come full circle on this post I started a few weeks ago. As suggested, I installed ISTA and read the pressures and fill times and sent to ZF. They responded very quickly, unfortunately it is bad news for me. Please see below

My Question to ZF:

I have a BMW 300xi with 110k miles. I am having an issue with delayed 2 - 1 downshift. I changed the ZF fluid, filter, internal gaskets, new solenoids and reset adaptations. The problem is still there but only when the fluid is hot, driving for at least 15 min. When cold, shifts perfectly and progressively gets worse as it warms up. I have listed the pressures and fill times for your review. I have driven about 150 mi since adaptations were reset. Is it unusual that clutch A and D are still zero? Would a valve body rebuild with a Zip kit solve the issue? Filling pressure and rapid filling time Clutch A: 0.00 mbar, 0.00 msec Clutch B: -274.0, 1.00 Clutch C: -300.0, -15.00 Clutch D: 0.00, 0.00 Clutch E: -28.0, 0.00

ZF response:

The adaption charge pressures look good. I believe you have a worn bushing. There are several shafts with brass or aluminum bushings, which wear over time. Once the transmission warms up, there is some leakage between a shaft and bushing. You typically won't be able to visually check them, because they all look good. There is a chance that you have a leak in the control unit, but bushing leaks are very common.

Eriksson Industries sells the bushing kits, Sonnax kits and ZF mechatronics.