MikeyTX

I just noticed that my trans temp is not showing above the 100* mark under normal driving. Does not matter if it is the pocket gauge or the single one displayed. Is this normal or has the temp sensor crapped ?

ddelallata

Normal

davepl

Normal.

With a conventional drivetrain layout the engine warms the trans a little bit, but they also share a cooling system. That means that the engine coolant warms the trans fluid in the radiator, so the transmission comes up to temp along with the engine.

I used to think that was important, but then:

In our layout the transmission is at the back and has its own dedicated cooler. The transmission can stay cold for a long time, and it apparently doesn't matter.

I do know that keeping a transmission cool can double or quadruple its lifetime when towing, but I thought too cold was bad too... turns out cold is fine.

ajrothm

I don't think I've seen my trans temp over 125* since I've owned it....

A cool trans is a happy trans.

MikeyTX

My thanks to both of you for responding. With the '16 Z being my third A8 C7 one would think I'd know. Especially since I keep the pocket gauges up all the time except for when I check oil life or tire temps on a cold morning.

SLWRNU

100* sounds way too low to me. Mine usually runs around 180-185 in normal street driving. Coolant around the same.
Oops I think I confused the oil temp with the trans temp. My bad.
Not sure what the trans temp is. Will look closer next time out so 100* or so may be where I'm at.

NSC5

A higher temperature does help keep moisture out of the fluid but I expect the system is sufficiently sealed that it isn't an issue in the C7. I recall one of the manuals that came with my Allison automatic equipped GMC pickups cautioned that sustained operation under 140 degrees was undesirable because of the possibility of condensation buildup in the fluid but in light usage the Allison runs about 140 in the winter time. It has a heat exchanger in the radiator tank but the fluid then goes to a stacked plate cooler in front of the radiator so it runs cold but has never been a problem.

I just looked at a PDR file from the mountains last summer and the peak A8 temperature was 118 so it runs very cool under most conditions. Peak oil was 221 and engine coolant was 209 for comparison.

MikeyTX

That's about where my temps were running when I was in OR and WA last Aug. At least i don't have a trans cooling issue. That was my concern.

8850

This is about the warmest I've seen my tranny temp. This was after idling for a long time in the staging lanes and right before shutting down after making a 10.64 pass.

Notice the engine and oil temps. Too warm!

Drew27

Do you have your log from the run?
Trying to see where your getting the knock retard at.
I would put a lmr thermostat housing with a zr1 160* stat to keep temps in low 180's.


Your cars pulling a lot of time with those temps

8850

The only channels I logged are in the chart above. Don't know where the kr is coming from for sure. I believe from less than high enough octane and maybe too high manifold temps. I've got logs with much lower temps and have recorded some kr. After adding Torco with same fuel in the tank kr went away the next day. Did not have Torco in the tank on that pass. Not sure if Torco would have helped with my temps that high but possibly.

A 160* tstat probably wouldn't have done me any good without the fan running faster and coming on sooner. Temps would still have risen until the fan came on via the factory tune. I would need to change the fan on temp and speed for a 160 to help. Not sure I want to void my warranty so soon either with the 160 and tuning. Hoping HPT tuner or Diablo will get the manual controls working for 2017 so I can turn the fan on without tuning.

If you would like to see my complete log and logs before and after the Torco I can send to you via email.