Interaction between 6HP26X and ATC500 (EGS and VTG)?
 

So here's an odd thing - yesterday I performed the xDrive oil change service (including the oil wear adaptations via DIS and using OEM DTF-1 oil) and now my transmission is shifting better than it ever has in the three years I've had the car.

WTH...? :confused:

It's only been one day, so I'm not holding my breath but the dreaded 2-1 slam is gone (or at least I can't get it to do it...) and the shifts are butter smooth, regardless of transmission temp.

So, is there some logical (in terms of EGS and VTG logic) connection between the transmission and the transfer case? Has resetting the oil wear adaptations (integration values) on the VTG reset something in the EGS?

Time will tell.... :popcorn:

So as time has gone on, did the fluid change & adaptation reset have a continued effect of reducing the 2-1 slam? or did this come back shortly after?

The 2-1 slam eventually (slowly) returned.

I recently replaced the mechatronic seal, bridge seal and jump seals in the ZF 6HP26X transmission, along with the filter and pan gasket (and *some* fluid).

After completing that work, resetting the adaptations and re-adapting the transmission, it's all very good again. Not perfect but very good. :thumbup:

2-1 slam permanent fix
 

Just an FYI for you guys with a 2-1 slam problem.
When my E53 got the problem, I did a detailed investigation as to the best fix for the problem and ended up replacing the valve body in the transmission with and after-market unit that has improved solenoids and other upgrades. Been over two years now and my transmission still shifts as smooth as butter with no service since installation. Here is a link to the unit I installed.

https://redirect.viglink.com/?format...mechatronic%2F

It cost me $600 for the install plus $1k for the unit for what appears to be a lifetime fix.

AceEngineer :cool: