Yes! Possibly a DIY would be in the works we hope, with a lot of pics. This is what I've saved to bookmark from xoutpost.com. This was an excellent read!

ZF 6HP26 Teardown - Xoutpost.com

 

wow, thanks for the link! and great story on how the 6 speed trans came about.
the trans look simpler than i thought it would be.

 

Right! I though you'd like that.

I would love to do a complete breakdown like this. Anyone got a ZF to donate?

 

Does it always feel like it slips or just sometimes at a standstill when you start to go theres a sort of slam coming from the back of the car as the gear catches?

 

yup

 

Same thing happened to me, its just a software update you need becasue BMW fitted a 6spd in a 5spd box so they had to use smaller clutch packs which wore faster and the update will recalibrate it.

 

how does a software update fix worn clutches?

 

It can't. But, with software, you can control the solenoid valves and thus the pressure at any given time to each individual clutch pack. The software update fixes a pressure/timing issue.

I have rebuilt a ZF 5HP24 transmission out of my E38 with over 200k miles. The clutch disks and steels were fine. In fact the steels still had machining marks on surface evident. Of course I replaced the frictions anyway. The most common failure point on the 5HP24's is a failed A-drum due to metal fatigue (the end of the drum holding the snap ring in place would break off. Second biggest failure is an o-ring. When an o-ring lets go, you loose the fluid pressure necessary to engage/hold the clutch. Result is slipping.

Unless the friction material has failed (rare) or worn significantly (rare again) the clutches are self adjusting. The piston simply moves further in bore to compensate for friction/steel wear. The transmissions even have built-in mechanical oil pressure regulators that compensate for oil pump wear.

Long story short. Failure is usually due to failed O-rings. The rebuild kits consist of new frictions and O-rings along with a few springs and other minor parts. Then there are valve body (Mechatronic) rebuild kits.

The rebuild process is tedious due to the hundreds of parts to you have to keep track of. The ZF rebuild manuals are a must. I made my own special tools. It is definitely doable.

 

Solenoids replaced on mine fixed the same issue. 30K miles with no issues.

is me replacing mine.. not hard

thectsc.com has them

 

nice video.

did you have to remove the valvebody to replace the solenoids?
whats the difference between the colors?
how much did they cost you?
are the solenoids variable, or do they just simply actuate on and off?

did you inspect or take apart the old solenoids, and inpsect for debris or obstructions?