Quote:
Originally Posted by mcastles
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.
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Just wanted to follow-up on my post from a few months ago, hoping it will help others.
I finally was able to pull the valve body on my 2006, 330xi and install a Sonnax Zip kit. It is imperative to get the number from the separator plate since the kits are specific. Mine was A052/B052 (Sonnax Part No. ZF6-6R60-ZIP). I purchased the separator plate and Zip kit off of ebay.
There are some very good videos describing the details of the valve body on the ZF 6HP19. Not difficult but very time consuming and attention to detail otherwise you will forget where the check balls, springs, etc go. The most difficult thing was removing the old regulator valves from the valve body since they are very tight tolerances. The Zip kit contains exact replacements but contain an O ring to seal. It also contains the new style accumulators that have a spring for tight sealing rather than rubber, which wears out on the OEM.
The only obvious things I found were the accumulators were worn out and the D clutch regulator valves were loose fitting compared to the others. Pulled out with no effort.
Bottom line, this solved my 2-1 hard/delayed downshift. I did reset the adaptions and the transmission shifts perfectly through all gears and no delay when the fluid gets hot. I have driven about 100 mi so far and still good.