[jethroreed]

Hey everybody. Recently I have been having trouble with the AT trans in my 08 335i with a DocRace ST. It currently has an xhp trans flash but is slipping in 3-4. It seems to slip pretty much any time I shift whether I’m in manual, sport, or normal auto. Car is putting down about 620whp and 590wtq. Even when I tune it down to low 500s it’s still slips. Also have had the issue where the yellow spinning gear pops up and I have to restart the car. Anybody know what the solution to this is? Is this most likely because I’m requesting too much power? Any info helps

[nicky dj]

Originally Posted by jethroreed

Hey everybody. Recently I have been having trouble with the AT trans in my 08 335i with a DocRace ST. It currently has an xhp trans flash but is slipping in 3-4. It seems to slip pretty much any time I shift whether I’m in manual, sport, or normal auto. Car is putting down about 620whp and 590wtq. Even when I tune it down to low 500s it’s still slips. Also have had the issue where the yellow spinning gear pops up and I have to restart the car. Anybody know what the solution to this is? Is this most likely because I’m requesting too much power? Any info helps

Have you done the transmission service; pan, oil, mechatronic sleeve and the solenoids replacement? I would definite start there first but you are pretty much at the threshold that the Z6AT can handle.

[Jeef]

get a replacement transmission

[feuer]

Originally Posted by Jeef

get a replacement transmission

Yes, preferably a manual transmission lol. Anyhow, I have good AT with only 75k on it for sale

[Smgs1992]

Manual swap. Service auto tranny and talk to your tuner to have him try to tune the torque down around low 500s. Might be too late on your current tranny though

[jethroreed]

Originally Posted by nicky dj

Have you done the transmission service; pan, oil, mechatronic sleeve and the solenoids replacement? I would definite start there first but you are pretty much at the threshold that the Z6AT can handle.

I haven’t yet! Will definitely check it out. Wasn’t planning on putting much more power down though. Oddly enough it isn’t happening today. It’s very on and off.

[zomski101]

Maybe the fluid is too hot. Do you have a trans cooler?
How many miles ore on the trans? Could be worn out valve body not supplying enough pressure on the clutches.

[Saif2018]

Originally Posted by jethroreed

Hey everybody. Recently I have been having trouble with the AT trans in my 08 335i with a DocRace ST. It currently has an xhp trans flash but is slipping in 3-4. It seems to slip pretty much any time I shift whether I’m in manual, sport, or normal auto. Car is putting down about 620whp and 590wtq. Even when I tune it down to low 500s it’s still slips. Also have had the issue where the yellow spinning gear pops up and I have to restart the car. Anybody know what the solution to this is? Is this most likely because I’m requesting too much power? Any info helps

Have you tried limiting the torque in gears and flashing custom settings ?

If I recall correctly XHP custom module allows you to do that for all gears.

Failing that, if you have done yh Mechatronic seals, valve body and Solenoids, with no improvement, your clutch pack might be done for.

XHP clutch pressure readings from adaptation values can also give you some sort of an idea of the condition of your clutch pack.

[mweisdorfer]

Originally Posted by jethroreed

I haven’t yet! Will definitely check it out. Wasn’t planning on putting much more power down though. Oddly enough it isn’t happening today. It’s very on and off.

If redoing the solenoids & Megatronic sleeves, coupled with a new filter & complete trans fluid flush doesn't work, you have 3 options really;

1) new or used A/T
2) manual trans swap
3) DCT trans swap

Options 2 & 3 are better than 1, but they won't be cheap, even with used parts.

Also, take xHp off when you redo the new solenoids.

Allow the trans to learn/relearn for a few hundred miles before putting xHp back on. I'm pretty sure you have to reset the transmission adaptations after putting in new solenoids.

[Saif2018]

Originally Posted by jethroreed

Hey everybody. Recently I have been having trouble with the AT trans in my 08 335i with a DocRace ST. It currently has an xhp trans flash but is slipping in 3-4. It seems to slip pretty much any time I shift whether I’m in manual, sport, or normal auto. Car is putting down about 620whp and 590wtq. Even when I tune it down to low 500s it’s still slips. Also have had the issue where the yellow spinning gear pops up and I have to restart the car. Anybody know what the solution to this is? Is this most likely because I’m requesting too much power? Any info helps

XHP latest update has custom line pressure bump for high horsepower cars,

You could try that and see if it sorts your slipping issues