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-   -   Transmission Rebuild ZF5HP24 Failure - Forward in Reverse! (https://xoutpost.com/bmw-sav-forums/x5-e53-forum/110880-transmission-rebuild-zf5hp24-failure-forward-reverse.html)

///Monster123 10-03-2019 03:59 PM

Transmission Rebuild ZF5HP24 Failure - Forward in Reverse!
 
2000 BMW X5 4.4 with the ZF5HP24 105k miles. I was getting trans failsafe mode and banging into 5th when fluid was warm. Reverse was working fine hot and cold. With all of the forum transmission rebuild success stories, I decided to rebuild myself.

I opened up the transmission and my A drum was in good shape the but the thin o-ring had failed and the roller bearing was also worn out. I decided to perform a full rebuild since I was here. I replaced the F-piston, all o-rings, seals, friction discs, and steels. I also ended up replacing the B drum and C drum due to damage and I put in an improved design regulator. Lastly, I measured end shaft play and ordered a larger shim to get it within spec. I did not rebuild, replace, or test any valves or solenoids because I thought they were working fine. I reassembled per the ZF manual and everything together well. I put on a rebuild torque converter, installed everything back on the X5. I leveled the vehicle by putting a level on the transmission pan and adjusting my jack stands. Then I followed the transmission fluid fill procedure. I pumped all 8 quarts of redline transmission fluid into it. I still didn't have any fluid coming back out of the fill hole but I was out of fluid and I thought I should be close enough for a test drive. I know I'll have perform the fluid level check again anyway.

The Test drive: After filling the transmission, I lowered the X5 to the ground, started it up, put it in reverse and......... I go forward. I understand that it is possible to get the shift lever a little off, so I played around with the shift lever for a while and I could not get the X5 to have reverse movement. I frustratingly push the X5 out of the garage and do a little more active testing. In drive, it goes forward and seems to shift through all 5 gears. It does seem a little laggy when shifting but it does ok. I floored it in Drive and I felt a slip on the 1-2 shift and I get the "bong!" [trans failsafe mode], that's strange.
Foxwell scanner shows 2 faults:
[31] EGS: symptom, gear monitoring
[32] EGS: Gear motoring 1
My understand is that those are faults for detecting a slip in the transmission.

Back at my house, I repeatedly shifted the transmission trying to get a different result:

Reverse only moves the vehicle forward. The moment I select reverse, I feel the drivetrain load up. The Reverse lights come on, Side mirrors adjust for Reverse. However the vehicle powers forward. If I drive forward in Reverse it seems to maintain only one gear, it does not try to upshift. It feels like I'm in reverse ratio too, just the direction of the output shaft is moving the wrong direction. Foxwell scanner shows gear position as "?" and solenoid valve 1 is On, with valve 2 & 3 off. This doesn't match what the ZF manual shows. If I'm understanding the ZF manual correctly, I should only have solenoid 2 on in Reverse.

Neutral usually puts the vehicle in Neutral but occasionally it chooses a forward gear and tries to move forward. I'm not sure what gear it's going into, it feels like 1st or 2nd. The Foxwell scanner shows shift lever position 1st and solenoid valve 2 is on with 1 and 3 off.

Drive and M1 put the vehicle in 1st gear. The X5 powers forward and shifts up and down according to speed and throttle position. At WOT I did feel the transmission slip on the 1-2 shift and received the trans failsafe fault. I think this could be a clue to my issue as well. Foxwell shows gear position "1st" and indexes up and down if I move the shift lever in manual mode. When in "1st" solenoid valve 1 is on with 2 & 3 off.

What mistake during rebuild could I have made that would cause forward movement when in reverse?

Any troubleshooting help or suggestions are welcome. I'm hoping RRPhil joins in because that guy seems to know these ZF5HP24 transmissions.

RRPhil 10-03-2019 06:58 PM

Did you definitely engage the pin on the rooster comb with the slot in the manual valve when you re-installed the valve body assembly?

https://i260.photobucket.com/albums/...PinEngaged.jpg

Phil

///Monster123 10-04-2019 04:16 PM

I remember the main valve being in my way when I was bolting on the valve body. I remember needing to slide it out of the way so it wouldn't be twisting/binding on the case. Now that you mention it, I can't specifically recall lining up the main valve with anything. That may very well be the issue. I've already drained the trans but it's still in the X5. I'll pop the pan off and have a look tonight. It would be nice if it really is this simple and I don't have to tear the transmission down again. I'll update after my findings.

Thanks for the suggestion RRPhil.

StephenVA 10-04-2019 08:05 PM

RRPhil is the trans man!

tmat1977 10-05-2019 08:27 AM

could be your transfer case or front drive shaft going bad happen to me same problems i had

///Monster123 10-05-2019 12:27 PM

https://lh3.googleusercontent.com/zF...J=w855-h625-no
This looks highly suspect. The main valve isn't connected, it's just fully extended.

Such a stupid mistake. I'm expecting this to fix everything but I'll post a follow-up after test drive. Hopefully this will be one of those forum questions that has an answer.

///Monster123 10-05-2019 09:27 PM

Test drive complete.

Eureka! I have reverse!!!

I recovered as much transmission fluid as I could but after taking a bath in transmission fluid (gross), I'm probably only 7 quarts in the transmission. I took the x5 for a quick spin but it was exhibiting signs of low fluid. So it's time to buy a couple more quarts red line D4

Thanks for the help RRPhil!!!

upallnight 10-06-2019 01:11 PM

Quote:

Originally Posted by ///Monster123 (Post 1169660)
Test drive complete.

Eureka! I have reverse!!!

I recovered as much transmission fluid as I could but after taking a bath in transmission fluid (gross), I'm probably only 7 quarts in the transmission. I took the x5 for a quick spin but it was exhibiting signs of low fluid. So it's time to buy a couple more quarts red line D4

Thanks for the help RRPhil!!!

I think that offering to buy RRPhil a pint at his favorite water hole would be a nice gesture. Think of all the money and frustration that you would have experienced if people like RRPhil didn't come on this forum to offer assistance. I have offer people on other forums a nominal reward when their suggestion solved a problem that I was having.


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