Originally Posted by langleyinLA

I own a 2001 4.4L X5 with 82K, and I want to share my recent experience with the ZF5HP24 transmission.

Symptons:

1) When I brake from 30 to 40mph to a stop, there is a "clunk" or a hard downshift in the transmission.

2) The X5 will not shift into reverse sometimes, especially in the morning. Sometimes in reverse, the reverse does not engage, except after stepping on the accelerator and rpm is 2 to 3K. Then the reverse would engage suddenly.

After seaching x5world and googling, I tried inexpensive ways to solve the problem.

1) reset the program (turn key on 5sec., turn off 5sec. and turn on engine)

2) replaced the transmission fluid and put in latest transmission software.

After the "inexpensive fixes", in addition to the original symptons, I had

1) when goin up a slight incline, stepping on the accelerator, I would have a sudden jerk. The rpm would increase and then transmission would engage. feels like being rear ended.

I own an auto repair shop and decided to bite the bullet and investigate. I removed the transmission, bought a retrofit kit and opened the transmission. I would like to mention that the transmission fluid was dark gray before changing, and was also a gray color when I removed the transmission (2 weeks new fluid).

I replaced the parts from the retrofit kit into the transmission and looked for possible causes. One of the o ring look very slightly worn. However, one of the clutch drum housing had very deep cuts in the groove from the clutch (highly unusual). It appears that was where most of the fine metal came from. I cleaned the valve body and did not change anything in it. I also replaced that the clutch drum housing (I am not sure if this is the correct term for the part b/c the groove is on the outside). We put everything back and

Hurray all the symptons were gone!

Coincidentally, the same time I was working on the X5, a 2000 328 with the ZF5HP17 transmission was also in the shop with a no reverse sympton. I had also found the noreverse.org website while investigating the x5 issue. Originally, we were just going to replace the transmission with a used one. After finding out from noreverse.org, we decided that a used transmission might have the same problem. So we opened the ZF5HP17, and found the exact problem as shown in the tranny autopsy. I have the part and could post a picture.

However, the cause of the no reverse in the X5 and the 328 was different. One, the lip of the drum was breaking whereas the X5 drum had cuts in the grooves. I do not believe they are the same drums though.

Hope this helps.