I've got a 2011 g37s coupe 7AT with rhfc, r2c intake and uprev tune. Was driving home and went to pass a car that was almost dead stopped and the engine downshifted without any notice and revved to the limit and sat there for a second and then banged into the next gear. It freaked me out so I babied it home. This hasn't happened again since (about 5 days now). Any ideas what this could be? Anyone else ever had this happen? I know my line pressure is up from the uprev but damn that was loud and I could really feel it. Think I need to worry? Also, I keep reading about these tranny updates, could I still get this tranny reprogram even with the uprev or would that be pointless?

 

What you are describing sounds like the way it behaves when you floor it and the transmission downshifts. Before you feel the push, you see the revs go way up while it does its downshift rev matching. The effect is particularly pronounced when it jumps down more than one gear.

 

I know what you are describing and have experienced it, but this was different. This was a much louder bang than normal. I guess if it hasn't returned and the car is running fine I shouldn't be worried?

If it did damage anything, how could I tell? I have manually shifted through the gears and it seems fine.

 

If you are concerned your best bet is to have the dealership do an inspection, however they may try to upsell you on a transmission fluid and/or differential fluid change. I personally would let that go until the services are normally required. If there is a problem they will replace your transmission at no cost, but a fluid change at this point may cause it to last until you are out of warranty. I have never heard any kind of bang noise on a hard downshift.

 

ok. Anyone know whether the deal would be able to tell if an uprev tune had been used? Do I need to go back to stack prior to them flashing the tranny update?

 

Unless they are really looking for a tune, they won't see it,but if they flash your ECU, and TCU, you will need a new cracked UpRev ROM, and hopefully your tuner will be able to just transfer the new MAP parameters.


Why don't you switch to the stock ROM via the cruise control switch.
See if the problem goes away, if it does, you know you're line pressures were set too high by your tuner.

 

Is this problem still happening or did it only happen once?

 

only happened once. She drives fine right now. Not sure what would have caused it tho.