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Old 01-14-2013, 12:21 PM
Piers1989 Piers1989 is offline
Officially Welcomed to the 'Fest
Location: Newcastle, UK
Join Date: Mar 2012
Posts: 302
Mein Auto: E65 745i
I went out in the car with my flatmate tonight looking at my laptop running diagnostics(status) on the gearbox through INPA.

It seems that the turbine speed (Torque converter output speed) is regularly less than the input (engine) speed. Even under relatively hard acceleration.

I don't know when out TC's are supposed to lock up, but even putting the car in 4th gear at a solid 3k RPM the turbine speed was fluctuating from locked at 3k and about 2.85k RPM, and the engine RPM was slightly fluctuating by maybe 50RPM.
The TC seems to be spending most of the time locked at speed but sometimes dipping to less than 1:1.

At lower speeds/RPM (when the car is doing the noticeable RPM fluctuations of 100-300) the turbine speed is staying at about 1200 though the engine speed is fluctuating between 1250 and 1450ish.

Also when coming to a stop the converter allows the engine to drop to its idle of 750 RPM while the turbine is still spinning at 1.2k RPM (I've been in several cars that did this, however I don't believe my last 7 did this).

Does this sound like a duff torque converter or normal operation, or indicative of an engine or gearbox fault?

EDIT: Also I cleared the fault log on the DME last week and no fault codes have returned. Also the Gearbox module has not reported any faults at all.

Last edited by Piers1989; 01-14-2013 at 12:25 PM.
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