4HP22 - Same issues after Master rebuild kit from ZF

[parlant]

Hi guys,

My late 1982 Euro 635CSI has a "lazy" reverse and has a hard time reversing at all uphill. Also, at high rpm the gears will stick. At low or part throttle, gears change normally and when needed it also reduces gear normally. I researched here in the forum and online and I read Shogun's descriptive work on the "F" clutch pack, among other things.

in light of these problems I ordered a master rebuild kit from ZF and replaced all those parts on the tranny. I did not touch the TC nor did I touch the valve body. I did replace the filter and fluid.

Put everything back together and the lazy reverse persists. I haven't tested gear change at high rpm yet.

Could the problem be the valve body only? I did not open the valve body but did not see any trace of gunk on it. Plus, since this is the early version of the 4hp22, there are no solenoids, it's purely hydraulic.

Could the culprit of my problem be limited to the valve body and maybe TC?

Thanks in advance for any advice!

[XAlt]

Filter and fluid.

[parlant]

Filter and fluid.

Yep, I stated above that I did that. Thanks anyways.

[XAlt]

Yep, I stated above that I did that. Thanks anyways.Read "not". Am schizophrenic, pls help

Maybe the valve body since there's full power in forward gears. Drop it and see, I doubt it's clogged solenoid screens. Check ball is suspect.

[Alika808]

Hey Parlant, my friend have the same issue but the reverse works when the car is cold. After a few minutes of driving, the reverse just doesn’t works after. I am wondering if ever figure out. Please up date. Thanks

[DesktopDave]

These old ZFs have a few problems with the wiring harness connector and their valve body...here's a few resources to get you started:
http://bigcoupe.com/phpBB2/viewtopic.php?t=25982

https://www.sonnax.com/tech_resources/163-zf-tips-with-a-european-flavor
https://www.rangerovers.net/forum/7-range-rover-mark-ii-p38/41322-zf4hp24-changed-fluid-drove-2k-miles-pulled-trailer-no-reverse.html

You haven't considered a manual transmission swap, have you? While the Getrag 265 is very hard to find, and the 260/5 can be problematic, the later 260/6 is often available at a very reasonable cost. It's been done many times with a terrific success rate.

[Dash01]

See Shogun's YouTube video on cleaning valve bodies, which have lots of tight passages and other places for crud to build up and cause your reverse to lag. Making sure you don't drop or lose anything, especially check balls, or damage the paper gasket. I've done this on an E36 GM tranny, which is not that different from ZF.

But, perhaps better Plan B would be to drop in a 5 speed, not that hard to find at PicknPull, etc.