E70 ZF6HP26 1st, Reverse and maybe 2nd slipping?
 

Hi All,

Got a bit of a strange issue and wondering if anybody could help.

I've owned this X5 for about 5 weeks now and overall love the car.

Most noticeably in 1st and reverse, when you set off, the revs rise but the car doesn't move as much as you'd expect then after a few thousand rpm it suddenly 'catches/grips/locks in' and it drives normally.

It does this in 1st and perhaps 2nd and it takes a few seconds for reverse to 'catch/grip/lock in' as well.

What I can say, is that if you're in 1st and you set off it has this behaviour but if you slow down to crawling speed and then put your foot down, it behaves normally, it's only when it goes into the gear from a complete stop it exhibits this behaviour.

I am used to BMWs in that I've had a few older ones now so I have ISTA and these are my adapation values.


Clutch Fill Pressures:
Clutch A: -32.0
Clutch B: 78.0
Clutch C: -265.0
Clutch D: -18.0
Clutch E: -126.0

Rapid Fill Times:
Clutch A: 40.0
Clutch B: 11.0
Clutch C: 6.0
Clutch D: 0.0
Clutch E: 53.0

Would anybody much more clever than myself be able to interpret if they show anything alarming?

I think I read the top number can adapt all the way to 750 before it will throw a code on the car?

Thanks in Advance

On a couple different bmw including mine I need to bring the rpm up to maybe 1200 to get the Torque converter to grab before I put down power. As long as I do that I get very smooth delivery.

I'm no expert, but my ZF 6HP28x was doing something similar a few years ago as shifting from 2nd to 1st and into reverse was starting to get less than ideal. Shifting into reverse it would jerk slightly and from 2nd to 1st it was like my brakes were grabbing too hard, at least that's the best way I can describe it based on memory.

Replaced the mechatronic sleeve, seals, solenoids, new pan and that solved my issues.

Yep. Sounds like it's time for a trans service if it's never been done before. "Lifetime fluid" my @$$. Thanks BMW.

You could try starting cheap with a mechatronic sleeve, tube seals, pan/filter, and new fluid (I like Valvoline Maxlife Syth multi vehicle as it's thicker than ZF and others). Reset adaptations. I've done this on 3 ZF trans so far with excellent results.

If that doesn't work you'd need the valve body serviced as well.