Going backwards while in drive

[yingste]

I had picked up a 2004 525i two weeks or so ago with several holes in the block due to piston 1. I have since removed the old engine and mounted in and connected a new engine from an e46 (Still an m54b25 so I only needed to swap over sensors mostly) but have come into a problem with the original transmission. The transmission is the same one that came with the vehicle and I had even driving off the trailer and into my garage. After fully reassembling the car and getting everything plugged in the transmission refuses to go into drive. The new engine works fine but the idrive says transmission fault. When I go into reverse the car goes backwards, when I go in neutral the car can be pushed but when I go in drive it will start moving backwards. When in drive it doesn't immediately start backing up, only after giving some revs will it clunk(no noise just a hard shift) and go backwards. I should mention that I have indeed checked the shift cable and it does move the shift lever fully in both directions. This is the ZF 6HP-19. I have also checked the large circular connector on the passenger side of the transmission but it seems to be plugged in correctly. Does anyone have any ideas what may be causing this?

[pbonsalb]

If you removed the pan, you probably did not get the lever back into the slot. If you did not pull the pan, I have no idea. Check reverse wire to trans. If not that, there are common problems with these trans you will have to look into like mechatronics sleeve leak and solenoid failures.

[White94RX]

You may have the shifter cable out of adjustment.

[jclausen]

Also check the wiring at the base of the shifter

[yingste]

I did pull the pan. It had a slight crack from when I had to put a jack under the transmission to get the right angle for removal. I took some pictures before I put the pan on since it looked interesting. Are you referring to an internal lever or the external lever that the shift cable attaches to?

IMG_20200506_142952.jpg

[pbonsalb]

On my 08 E61, I did not put the pan back on perfectly and the shifter was out of the track or slot so the trans was in the wrong gear. It was 4 years ago so I can’t describe it well, but I think there was a lever or fitting that had to be in exactly the right spot and I forgot to make sure it was. Had to pull the pan, full of new oil that I wanted to reuse, and reinstall. No idea whether this could be your issue.

[White94RX]

If you only pulled the pan off, and didn't pull off the valve body, then I doubt it would be possible to move the linkage or anything like that.

Like I said before, you may have the shifter cable out of adjustment. Have you checked it or readjusted it properly?

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[yingste]

I can go and check the cable again tomorrow. Is there anything specifically I should look for? Right now I feel each click or detent of the shifter when I move it down from Park to Reverse, reverse to neutral and so on. The corresponding light also illuminates on the shifter trim.

[pbonsalb]

Good point. I think the problem I experienced was a slot in the valve body, which I had removed.

[scottalexander]

Gary Ferraro (on Youtube) has torn down countless ZF 6hp19's.

In one of his videos he shows the exact measurement and space required for the shift lever cable.

[White94RX]

Adjusting is pretty simple. Break loose the 13mm nut that clamps the cable. Make sure the gear shifter is locked in park. Rotate the shift lever on the trans and make sure it is also on park. Then lock down the nut.

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[yingste]

Okay, that's how I did it before. When I get the chance I'm going to double check the fluid. It only took 6 L when I hear that it should take around 10.

[White94RX]

It only takes that much if the torque converter was empty. If all you did was pull the pan off, then the torque converter is still full and around six quarts is right.

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[yingste]

Thank you everyone for your help. After finally getting time to work on it again it turned out to be two issues. The first being I needed to redo the shifter cable and the second being low fluid. It ended up taking about a full gallon of fluid once I let it get up to operating temperature.

[White94RX]

Glad you got it sorted. Thanks for the update.