On my 700r4's, I can tell when it locks up, not so on the A6.
What gears will it lock up in?
Will I see or feel a slight drop in r's?
I read here that a slight increase in efficiency/cooling can be obtained by keeping it in a lower gear at moderate speeds to take advantage of lock up. Is this true?
Thanks, did a search to no avail.

 

My A6 locks up in 6th gear at about 47 mph. And yes - you can see a drop in rpms when the lock occurs.

 

I checked out the 5th gear on the hi-way theory.

Results
2mpg less instantneous reading
2 degree warmer (in 90's Texas temps )

 

Thank. Found this after a "5th gear lockup" search. Going to do some more digging and driving.
MisterMidlifeCrisis
CF Senior Member
2011 Chevrolet Corvette


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Member Since: Oct 2006
Location: Redmond WA

I think the lockup happens in gears 2 through 6 after a couple to a few seconds of low to moderate throttle at lower engine speeds. I've never noticed it happening at higher engine speeds and zero to very light throttle such as when downshifting and then just breathing on the throttle to maintain handling balance. It might also be that it won't lock up once cornering forces exceed some limit.

But what you are feeling is normal. You'll probably also notice that once it locks up, a paddle shift takes longer to accomplish, as the transmission has to unlock before the shift. Now that I've said that, it'll probably start bugging you. Sorry!

 

Hopefully this will give you some insight into what's going on. The ECCC portion is meant to reduce NVH (noise, vibration, harshness) when the torque converter locks up at low engine speeds by not actually locking up. This is meant to avoid low RPM light load torque converter slippage when no torque multiplication is needed but you're still well below the stall speed of the torque converter, a very inefficient area of operation but an area of operation that occurs often in normal driving. In order to go after MPG gains, GM uses the ECCC to eliminate/significantly reduce the slippage in this zone of inefficient operation while maintaining acceptable levels of NVH. At higher engine speeds, the torque converter fully locks but ECCC is still used to apply the clutch slowly so lock up occurs seamlessly to the driver...this is why you don't "feel" it, ECCC is doing it's job.




This gives you a little more insight into how ECCC actually works. Full release pressure is applied while the apply pressure is regulated to control the amount of slippage. Release pressure is exhausted and full apply pressure is sent to the torque converter clutch during periods of full lock up. The TCC PC (torque converter clutch pressure control) solenoid is the main player in ECCC operation and is controlled through the TCM (transmission control module).

PS The first text is from the FSM and the second text and diagram is from a book with very detailed information on the operation of the transmission.

 

Thank you, glass slipper.

Nothing like printed facts to answer to a question.

 

Thanks a lot for the info.

"At higher engine speeds, the torque converter fully locks but ECCC is still used to apply the clutch slowly so lock up occurs seamlessly to the driver...this is why you don't "feel" it, ECCC is doing it's job."

Cool.