zf6hp26 shifting 2-1
Posted: Tue Aug 01, 2017 11:41 am
A wellllll discussed topic I know... however I thought a discussion about some recent findings might be useful...
Background: Since I bought the car (2004 3.0d x5 sport) it shifted harshly down from 2-1 when just about coming to a halt. Funnily enough it didn't do it on the test drives, but I wasn't aware of the issue then so didn't 'look' for it. Anyway, as time went on the g-box started to make more noticeable shifts and the 2-1 lurch was annoying me. It also seemed to be 'gear-braking' as I was slowing down coming to lights etc which I was worried about.
So, I took off all the covers etc under the car and discovered a leak from the 'sealing sleeve' at the back of the gbox.
Following this I recently changed out the transmission filter and refilled the approx 6litres of atf using oem bmw fluid. (While there I also changed the transfer case fluid and both diff fluids). Having put it all back together I test drove and the 2-1 shift was gone... for a while. Next mve was to reset the shift adaptations on the transmission with INPA... this initially made the shifting poor (I was really worried then!) but it improved over a few miles which was a relief!
The shifting was then back to my 'normal' but rid me of the 'gear-braking' which is good. After some more reading I tried the 30 second accelerator to the floor throttle reset. This made a fair difference to the shifting (someone may be able to tell me why) and the 2-1 thud on stopping was gone for a while which was amazing! However it has returned intermittently, probably in something like 90% of stops now.
What I find interesting is that the g-box CAN shift fine so the problem shouldn't be mechanical, but more of a communication/electrical sensor or timing issue... does this make sense to anybody else? Coupled with the suggested 'switch to sport mode when slowing down' that also works (as does using 'manual mode' and keeping it in gear 2 until stopped) this suggests a computer based solution. Yet, the more I read on the topic the more I see people paying out £££'s for the software update and not seeing an improvement.
Is there anything i'm missing here? I don't have the money for a new gearbox or a rebuild and to be honest it doesn't seem necessary when you put all the evidence together.
Does anybody here think it's worth trying a software upgrade based on their own experience? Can't buy into the 'this box just works like that' because no-one in their right mind would drive out of a showroom in a car this expensive operating like this. At the end of the day I can live with it jabbing me in the back at traffic lights, but i'm sure there's somebody out there who can shed a bit more light even on such a well-discussed topic... we'll I hope so anyway!!
Thoughts, experiences, suggestions most welcome.
Background: Since I bought the car (2004 3.0d x5 sport) it shifted harshly down from 2-1 when just about coming to a halt. Funnily enough it didn't do it on the test drives, but I wasn't aware of the issue then so didn't 'look' for it. Anyway, as time went on the g-box started to make more noticeable shifts and the 2-1 lurch was annoying me. It also seemed to be 'gear-braking' as I was slowing down coming to lights etc which I was worried about.
So, I took off all the covers etc under the car and discovered a leak from the 'sealing sleeve' at the back of the gbox.
Following this I recently changed out the transmission filter and refilled the approx 6litres of atf using oem bmw fluid. (While there I also changed the transfer case fluid and both diff fluids). Having put it all back together I test drove and the 2-1 shift was gone... for a while. Next mve was to reset the shift adaptations on the transmission with INPA... this initially made the shifting poor (I was really worried then!) but it improved over a few miles which was a relief!
The shifting was then back to my 'normal' but rid me of the 'gear-braking' which is good. After some more reading I tried the 30 second accelerator to the floor throttle reset. This made a fair difference to the shifting (someone may be able to tell me why) and the 2-1 thud on stopping was gone for a while which was amazing! However it has returned intermittently, probably in something like 90% of stops now.
What I find interesting is that the g-box CAN shift fine so the problem shouldn't be mechanical, but more of a communication/electrical sensor or timing issue... does this make sense to anybody else? Coupled with the suggested 'switch to sport mode when slowing down' that also works (as does using 'manual mode' and keeping it in gear 2 until stopped) this suggests a computer based solution. Yet, the more I read on the topic the more I see people paying out £££'s for the software update and not seeing an improvement.
Is there anything i'm missing here? I don't have the money for a new gearbox or a rebuild and to be honest it doesn't seem necessary when you put all the evidence together.
Does anybody here think it's worth trying a software upgrade based on their own experience? Can't buy into the 'this box just works like that' because no-one in their right mind would drive out of a showroom in a car this expensive operating like this. At the end of the day I can live with it jabbing me in the back at traffic lights, but i'm sure there's somebody out there who can shed a bit more light even on such a well-discussed topic... we'll I hope so anyway!!
Thoughts, experiences, suggestions most welcome.
