[AJ@ECSMotorsports]

Hey guys,

Did searching and nothing similar to my issue excelt a random message for the most part.

For a few weeks now, under hard acceleration usually 60+ mph, I get a hard jerk. More and more lately I've seen this happen under slightly less harder acceleration.

Today, twice back to back, I see the RPMs really high, about 6K or so, as if it didnt shift, and I see boost go to about 10psi or so.

I have a JB4 installed for over 2 years, never touched. performance *seems* to be the same. But twice today this happened and I tried to replicate it under lower circumstances, and bam, the "Trans. Malfunction" warning popped up. I made it the 1/2 mile to my home, turned it off, back on and seems back to normal. But I know the problem is still there

Anyone have any useful insight to this issue? I rather find out before I take it in, as I am out of warranty as of April. The jerking seems to be worse.. when I searched for the jerk issue before, I saw everything from fuel pump to wastegate issues, so I never go to diagnosing it, but after today I feel but hope its not a bad issue.

Thanks guys! I will try to pull codes from it later today, if there's any besides that for my downpipes.

[Pr335bob]

Check if your leaking transmission oil common issue in our cara aftee 60k. Also is it a gear and a exclamation point ? What does the warning sing look like? Mine only happened once with warning but it was a jerk and when switching gears a sign with a gear popped out. I turned the car on and off and it acted normal this was 3 years ago hasn't happened since. It was scary when it happened but just happened once your description kind of remind me of it .

[AJ@ECSMotorsports]

Yeah, it was a gear. Said to reduce speed and have it checked out. Car drives just fine now, but the jerking seems to be a continuous issue. I can't get my USB to recognize the jb4 from laptop to read codes...

Any other ideas? I'm sure the jerking caused he symbol/notification but just wanted to get klutz on possible causes from you guys before I start dropping money to have it simply looked at

I don't have any known leaks.

[Ilma]

A lot of AT's seem to be experiencing frayed transmission wires in the shifter mechanism which causes various symptoms of transmission issues.

In my case I lost DS mode entirely and the car would stay in one gear only.

I followed the instructions in this thread: http://www.e90post.com/forums/showthread.php?t=511799 and found that 6 of my wires were either partially cut or completely severed.

I think it is a common problem and probably affects all 6AT's at some point since it points to being a design flaw in the wiring harness inside the shifter mechanism.

You may be getting intermittent electrical issues if your wires are becoming progressively frayed over time.

the problem tends to go away once you slap the shifter back and forth since the wiring harness moves with the shifter and doing this can re-establish contact in the frayed wire.

It may or may not be your problem.....but it's worth having a look!

[ajsalida]

Couple of things.

One is the idea of lifetime AT fluid is probably a fantasy, certainly so with any kind of FBO or beyond. So I agree with previous poster 60k is time for fluid and filter change. After you do that reset TCU adaptations using INPA or similar (NOT the gas pedal thing) and be sure to do the prescribed adaptation period before using heavy throttle.

The other thing is 4-5 shift under load is notorious for causing all sorts of problems, timing issues etc. which are not entirely resolved for AT cars. Whole system getting hot mid summer all kinds of things will become apparent.

Finally stuff breaks, gets loose, etc. Motor/tranny mounts, exhaust hangers, even DP's get loose and creak shifting around under load.

[AJ@ECSMotorsports]

Yeah a tranny flush/change is what I was thinking as that cannot hurt.. May as well have a local bimmer shop read my codes and diagnose nay other issues/reset, etc..

Will see tomorrow hopefully!

[AW750Li]

Had the same problem with jerking under hard acceleration. I went to the dealer and had a mechanic ride in the car with me to show him the problem. The dealer ended up changing the transmission and the problems went away.