ATHENSG37

I haven't really been able to find much about this and only found one post regarding something similar happening but with no resolution. When im driving (which im always in sport mode using the paddle shifters) in pretty much any gear or speed and let off the gas the rpms will drop down to like 1100 rpm or so give or take and feels like its just coasting. I can be at 3000 rpm and let off and it drops and when i hit the gas it shoots back up. I know the torque converter is probablly locking at certain speeds and gears but it does this ALOT in any gear and sometimes it doesn't do it at all which is confusing and I cant seem to find a pattern to this issue. Sometimes it seems like it improves when the car is more warmed up but sometimes its the same which makes this difficult to figure out. Anyone had this issue or any techs on here have an idea? Car has 66,000 miles.

Conboss

I’ve found that my trans does this when it’s hot. After a solid drive around and the temps getting up there, it feels like the torque converter just drops out. I’m used to it being locked in sport (also primarily drive in sport, manual shifting) but it feels like it just falls apart. If i rev it back up it’ll sometimes shoot past the target RPM then settle back in when the torque converter locks back up. I’m stumped as to what it could be though

ATHENSG37

Mine does that too but temperature doesnt seem to be much of a factor in my case.

Conboss

there are days where I find temp doesn’t affect it, but it’s few and far between. Maybe I’ll see if I can throw a scanner on it and check out parameters. Not sure how I’d do that, but I’ll see what I can figure out

SonicVQ

To read/check the TCM for codes, you will need something with enhanced diagnostics. OBD Fusion with their enhanced diagnostic add-on can do this. (I have done it many times)
By the way, a TCM code usually doesn't turn on the check engine light, so you might have some codes and not know it.

If the torque converter is not locking up, you should see a P0744.

Conboss

Just back from a drive and it was all over the place. I was stuck in traffic and on back roads in one drive, it did not want to cooperate in the traffic. Engine was getting hot, fans on in 33C weather. It came back in the back roads but there were still moments when it unlocked. Sometimes it would hold on for a couple seconds then let go.

ATHENSG37

I just had the TCM and ECM software update done yesterday the 9th and so far I have not noticed the weird rpm drop anymore but I havent drove it a ton either. Throttle response is also more responsive after the update as well as smoother shifting when taking it easy.

ATHENSG37

update, still does it..seems like the warmer the car gets the more it does this. Also noticed when i was in 6th gear going about 45-50mph and hit the gas it would jump to 3k rpm which is way too high for that gear and if i let off the gas it would drop back to about 2k rpm where it should be. If I held the gas down it would stay at 3k rpm for 4-5 seconds and then go back down to about 2k rpm. Not throwing any codes but this behavior seems really strange to me.

kingraj

any update bro ?? having this issue now

Conboss

I’ve switched G’s, bought a coupe with the same 7at. Just last weekend I did an ATF change on it, it was also flushed. Fixed some oddities in the way it drives, but the issue is more or less consistent. It was hot again this week, so I’m still under the impression that is has something to do with fluid temps.