Paddy525d

My car is currently at a "bmw specialist" and he can't seem to find my fault, I was wondering if anyone could help me. I'll post what I saw him post on a different forum.

I've got an issue with a ZF 6HP26 regarding TC control I'm hoping you can help with.

The car belongs to a customer of mine, basically when driving from say idle engine speed the TC won't fully engage until about 1800rpm, gear shifts won't happen until about 2300rpm so very delayed, when braking the revs will slowly come down with vehicle speed until about 1300rpm and then the revs will just drop to idle so TC fully disengaged, and won't fully engage again until 1800rpm as before, on thing I've noticed when giving the car some stick then braking the TC will be correct momentarily and come down to 1000rpm no issues but then as you attempt to drive normally again will go back to how it was.

Now the box has been serviced so new ZF sump and fluid along with new bridge seals and tube seals for the valve body, no different, TC remanufactured, no different, valve body rebuilt with a seperater plate and a sonnax zip kit plus a new EDS6 TCC solenoid, no different, box was removed and the following parts replaced, front TC seal on the pump, pump outer o ring and inner o ring, New stator bushing, New seal rings on the rear of pump and input shaft, New e clutch intermediate bushing and one e clutch friction replaced due to wear on the outer edge, all other bushings and clutches related to A and B were checked and fine, I didn't removed the central support for C and D as didn't see the relevance but after all that no different, valve body with mechatronic sent of for testing and remaining 6 solenoids tested at the same time, all checked out fine, gearbox heat exchanger replaced and no different.

All I've got left to try is a software update I think or remove the box again and check the rear half which I'm not keen on doing again atm.

Before I thought it might be to do with worn bores on the wk-v or wd-v but with it testing fine was at a loss with that.

I'm certain it's a pressure related issue but I'm running out of ideas, with it being momentarily ok after some hard driving it's starting to make me think it's oil pump related or the extended increased pump speed has increased internal pressure overcoming an internal pressure leak but I'm just at a loos as to where it could be.

E60Japanese

Have they found the problem yet?

Paddy525d

Not yet