Zf 6 Speed Auto Not Changing From 3Rd T 4Th

[mr_crust]

evening all,had an issue today with the zf 6 speed auto in the xr6. in short I have no issues in 1st or 2nd but when in 3rd it wont change to 4th...3rd gear just revs out. I have backed off and accelerated again but it wont engage 4th. if I use the performance mode I have no issues going between all gears. I had it an an auto place and there scanner was unable to read the error codes. anyone heard of this type of issue or the cause of it ?? it sounds electrical to me, possibly a solenoid. oh and its booked it Monday to get diagnosed but im curious what it maybe and what to expect

[bionicxr6t05]

Fooked mechatronics...

Edited 17/08/12 11:52 AM by bionicxr6t05

[Vevapower]

Nothing to do with mecatronics.. your E clutches are on their way out it's really that simple!

[bionicxr6t05]

Both can cause the same issue... But yes clutches are more likely if its modified

Edited 17/08/12 11:55 AM by bionicxr6t05

[Glouva1]

It's the clutch more likely than not as always seems to impact 3rd to 4th change.

[Vevapower]

Mechatronic only reacts to its physical components,oil characteristics and sensors so to say its the mechatronic itself is not correct. If all componentary wise in your box was fine you would not have any issues with slip yeah! You see once you burnt up frictions there's no way they'll come good again and they just get worse. So what's happening in your box atm under load between 3rd to 4th is that due to the slip (E clutches in bad shape) the speed sensors are saying to the mechatronic " hey man there's way to much slip going on here so there's no way I'm going to let it change up to 4th". So what usually happens is that it will either rev out or you inadvertently lift off enough whilst this is happening enough to lower the load enough for the mechatronic to then say hey I'm good now and it will thud into 4th.

Now as wear continues to get worse over time it will refuse to change under less and less load.

A ZF tune might mask it for a while with more line pressure but in time you will still have the same result.

Hope this gives you a little bit of insight.

.

[mr_crust]

Thanks for the quick replies, If it is the clutch pack does that require a gearbox rebuild or can they be changed? Or same deal withe mechtronic can it be replaced without a rebuild

[rednose]

Rebuild, mine does the same, if I shift into 4th at WOT the box won't change up, the speed sensor detects too much slip and says hell no and just bangs into 3rd again, so I lift off and it will then engage 4th.

Normal driving is fine, it only affects me higher up in the rev range.

These boxes are designed to slip but when you double your power and torque they really need to be beefed up with extra clutch packs otherwise they won't last too long if given a hard time.

[mr_crust]

I've been running 287rwkw for almost 12 months, so the box has had to work a little harder...what has me puzzled was, the last time I drove the car 4 weeks ago it was fine but when I went to take it out this week I noticed oil on the floor under the box and then this issue.....im still sit in hope its not a rebuild but if so what extras do I need to strengthen it?

[sexual harrassment panda]

Did your tuner turn off the torque truncation?