View Single Post
Old 01-16-2019, 08:04 PM
wpoll's Avatar
wpoll wpoll is offline
Join Date: Sep 2015
Location: South Island, New Zealand
Posts: 2,525
wpoll will become famous soon enough
Originally Posted by RRPhil View Post
Without doubt, the single biggest problem with the 6HP26 is faulty solenoids. These cause the vast majority of issues with this transmission. The other main issues are:
  • Transmission refuses to shift higher than 3rd gear (E-clutch slipping due to hydraulic leakage caused by wear in lead-free rear stator bush)
  • Clunky 2-1 rollout shifts (Latest mechatronic firmware updates not performed)
  • Clutch packs destroy themselves following fluid change and adaption reset (ECU cannot find new adaptions in time to prevent clutch plates burning up, due to change in friction coefficient)
  • Complete loss of drive (Failure of output shaft spline through fretting corrosion due to lack of lubrication at factory)

Mechanically though, I would say it is a more robust transmission than the 5HP24. Having said that, Audi put the 5HP24A behind their 6.0 litre W12 engine and even the 353kW/560Nm Audi RS6 Plus, so the 5-speed running gear is certainly capable of handling more power/torque than the 4.6iS E53 delivers.

Wow - thanks Phil!

I've always wondered about the mechatronic firmware and the 2-1 slam - assume you are referring to the EGS module firmware. Does' anyone know exactly WHAT the latest version is (and more to the point WHERE it is... ).

And interesting comment about the adaptations. I've always thought that damage was a possible outcome of adaptation resets (when not required) - interesting to hear this is the case.

So if the mechatronic firmware is updated, I'm assuming that process erases the adaptations, or are they stored in a separate register and are re-applied via the new firmware?

Interestingly, I had (have) a mild case of 2-1 slam on my 6HP-26X but when I recently replaced the ATC500 power divider fluid and performed the VTG oil wear adaptation reset via DIS, the 2-1 slam disappeared. Mostly. I can still induce the slam but the car rarely does it and it's now SO much more drivable, especially coming up to Give Way signs in hill suburbs.

I have no idea why - but I'll take the win!!
2005 BMW X5 3.0d (b 02/05)
2001 BMW F650GS Dakar (b 06/01)
Reply With Quote

Sponsored Links