2008 Z4 Transmission Question

[hawkerone]

1 month new to BMW Z4 ownership. While in Drive, I gently start off to what seems like a noticeable downshift followed quickly with an upshift. Rest of acceleration seems fairly smooth. Deceleration seems normal enough until almost stopped when I detect a 'clunk' of a downshift. I realize I'm sitting beside of the differential so might be nothing but normal operation. Just wanted to get opinion of more experienced folks on here.

[shogun]

Moved to Z4 forum

[dln9749]

1 month new to BMW Z4 ownership. While in Drive, I gently start off to what seems like a noticeable downshift followed quickly with an upshift. Rest of acceleration seems fairly smooth. Deceleration seems normal enough until almost stopped when I detect a 'clunk' of a downshift. I realize I'm sitting beside of the differential so might be nothing but normal operation. Just wanted to get opinion of more experienced folks on here.

After about 60K miles, the mechatronics seals begin to leak. 1st indication is a 2-1 bump, felt especially while making a quick stop. It feels like the trunk is full of water, sloshing forward. Another indicator is a hard upshift from 1st to 2nd from a slow roll to quick acceleration. The fix is replace the seals between the transmission body and the mechatronics. Get a complete kit @ FCP Euro for about $325. Use TIS for DIY instructions. Because you can't easily access the electrical connector for the mechatronics, you have to drop the exhaust and rear tranny cross brace.
Good luck!

[jclausen]

I would also check transmission adaptation numbers with say an auto logic + or - up to 300 is within spec

[hawkerone]

Thanks, very helpful. This sounds like exactly what I'm experiencing. Found the FCP Euro site and kit you refer too. Going to talk to shop tomorrow about getting it done. I appreciate your help.

11/17 - Ordered the kit from FCP Euro. Hope it includes everything I'll need. (nearing the end of this restoration project - Do they still have Debters Prisions?)

[hawkerone]

Kit should arrive today. What is TIS instructions and where do I find it ? I'm having it done by a good shop so they probably know everything about it but I like to hand them the complete package including instructions so no missed steps. I'm feeling confident this is the answer to the problem. Thanks for the help.

[Clearancediver]

BMWTIS.com You will need to pay for access.


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[hawkerone]

Follow-up om transmission problem. Did the transmission filter change as suggested above. That didn't fi it. Next I took it to transmission shop where they changed the filter and fluid again. That still didn't help, so they wanted me to install a remanufactured tranny. I balked and had them reluctantly replace the solenoids. This seemed to fix most of it. I then had the driveshaft center bearing and coupler replaced and this seemed to take care of the problems finally. A lotta $$$ expended. Not sure if I had it to do over from the start I wouldn't have been better off just replacing the tranny,, but it is what it is.

[Caver69]

My Z4 2008 (82k mi) when purchased. had the balky downshift 2-1 and it would howl around 4000rpm on upshifts occasionally. Diagnostics had a code for one solenoid that reset and stayed clear. My mechanic did the filter & flush, the seals, and all six solenoids (my choice not his). Tranny is like butter, no howl, no bad shifts, and no 2-1 bump. My guy was actually surprised that hard seals caused so much trouble.