5th gear low rpm problem

[hansv1]

So i had the standard issues of the slipping tranny (ZF) due deteriorate ring in the torque converter so i had the TC replaced. Went ahead and had the reverse drum (?) replaced as well since they are known to go bad. Went to a reputable indy shop, definitely knew what they were doing, got their name from this forum, so thanks all.

The problem; ever since the torque converter replace, the car shifts into 5th seemingly 'too soon', dropping RPM's to 1500-ish going 4th to 5th. The motor seems to wander a bit looking for the best gear at that RPM range, then typically it shifts to 4th, then as speed is gained it shifts to 5th (now we're around 50mph) and all is well. Shifts fine through the rest of the gears, no problems. Oh, and it only exhibits this issue when warmed up, and it happens consistently once warmed up.

I have done the infamous reset of the adaptive transmission program mapping, to no avail.

Any thoughts here? The shop said the reset the software, assuming they meant did the adaptive reset...

Any help or ideas, or others suffering from the same issue would be greatly appreciated.
2003 E39, ZF Transmission, M54 motor

Looking forward to getting her back to 100%.

Thanks,
Hans

[hansv1]

Any ideas guys?

Thanks for any help you can offer.

Hans

[dima869]

Do you have any faults stored in the EGS? there is a bulletin out about the valve body wiring harness. It could be a possibility, and it's not something a tranny shop would necessarily replace.
good luck

[hansv1]

Thanks for the reply.
No faults in the EGS, had that checked by the stealer a week or so ago.

Could improper fluid level be the culprit?

Hans

[g00dwagen]

Based purely off the symptom, previous repairs notwithstanding, it sounds to me like a faulty TCC. (torque converter clutch).

Your indy should be able to monitor live data while driving the car & hopefully catch it toggling in and out of lock up. They had the foresight to overhaul the low/reverse drum while the tranny was out, hopefully they can get to the bottom of this problem.

FYI, after having been burned too many times, I insist on ZF reman torque converters on all 5HP19 transmissions. All reman units are not created equally.

[Critter7r]

Does it perform any better in Sport mode?

[hansv1]

Thanks for the replies.

Not sure which reman TC was installed, i'll have to ask, hindsight on this one.

The symptom is lessened in Sport mode, but still there a bit.

You know, it actually acts like a vacuum leak. I watched it closely on the drive home from work today and (after dropping into 5th) it tends to wander from 1500-1800ish and back ('ish' meaning it's hard to tell with the stock tach) then it shifts up to 4th and back to 5th when it gets to the speed it wants. In Sport mode the wandering of rpms is definitely lessened.

Sheesh, i wish i weren't so picky about the performance of this car, but then again...

Thanks again guys for all the help!
Hans