2001 4.4 replacement trans, no reverse? Update, Fixed and driving!
 

I picked up a 2001 X5 a couple months ago with a bad trans, looked like the infamous "A" clutch failure (http://www.xoutpost.com/bmw-sav-foru...x5-issues.html), found a used trans from a running and driving 2001 X5 and picked it up. Today, I finally got around to buttoning it all up, get it started up and it seems forward gears are perfectly fine, but absolutely nothing in reverse. It is still up on jack stands so there is not even any resistance at all on the wheels to spin but still nothing at all in reverse, I would think that even if the trans did have the F clutch piston seal failure that being up in the air I would get at least some movement, but I get nothing at all.

I can't seem to find my scanner right now, ordering a bluetooth scanner off Amazon tonight, so until then I can't even check to see if there are any codes.

Is there any other failures that could cause this that would leave the transmission with no movement at all in reverse?

Just found this, ZF Tips with a European Flavor - Sonnax

I will check out the wiring tomorrow after work.

Unless you have the App Icarly, I don't think a generic bluetooth scanner will be able to read the TCU / EGS module. Do you see the R in the dash display when the shift lever is in the R position?

Yes, dash displays R, reverse lights also come on. I am thinking that this means the switch is operating correctly, going to check it anyway as its a quick check.

Did you verify that the used transmission was in perfect working order prior to obtaining? Because if you didn't its just a roll of the dice.:yikes:

I was assured it worked, from a very reputable shop in a good area known for working on BMWs, got the trans for much cheaper then most I have seen though. If it turns out to be an internal failure I will surely contact them. I definitely agree on a roll of the dice with a used trans, but for the price vs time to rip into mine and fix it I just wanted a quick in and out swap. The plan was to rebuild the original and have it ready to swap back in if there was a failure or find another X5 with a bad trans and pick it up to swap in. The good news though is now at least if I have to take it back out again I can have it done in less then a day.

If you check the transmission serial number on the green plate on the LH side of the maincase, if the number is higher than 0424941 (i.e. a build date after 29th August 2001) then the transmission has the latest, upgraded, F-clutch piston. I’ve never yet seen one of these fail.

What the Sonnax article is saying is that if you disconnect the 16-pin plug at the back of the transmission you can deliberately put the transmission into failsafe mode.

http://i260.photobucket.com/albums/i...pscxxgfsya.jpg

Failsafe mode provides a direct hydraulic path in reverse, via the manual valve, to the C & F clutches without risking any intervention from the MV3 solenoid or the reverse gear protection valve (RG-V).

http://i260.photobucket.com/albums/i...08/RG-VMV3.jpg

If the transmission will then reverse, you have an electrical/electronic fault rather than a hydraulic/mechanical one.

Phil

Thank you Phil, I have read countless posts on these transmissions with your input and it really shows you know what you're talking about, I was hoping you would jump in!

Have you ever known one to be so bad of a failure that even up on jack stands with all four wheels off the ground there is still no reverse?

I agree that you would expect a small amount of clutch drag, and hence torque on the output, even if a seal was leaking or there was a mechanical issue. Maybe it does indicate that reverse isn’t even being signalled to engage (valve body assembly issue?). Anyway, best to carry out the test.

Phil

Disconnected the harness, still no reverse, sadly just like I expected.

The engine seems to have a load on it when in reverse, you can hear it drop in RPM slightly like it normally would so I know there is something going on in there. Hoping to get this nailed down before the weekend, if it needs to come back out I want to have it out and ready to go back in by the end of the weekend.... if I have time haha!