Thread: ZF5HP24 Hunting and vibration. Whats wrong?

When was the transmission last serviced?

I'm sure it has been quite a while. I have only owned the car for a few months and my first order of service was to change the timing chain and guides.
I bought the car with serious guide and chain issues so did not drive it before purchase (was happy with this given the price I paid).

Given that the previous owner let the engine get to the stage it did, I suspect it has been some time since a service.

Whilst I could see how a device may help the hunting in and out of overdrive, would it help the vibration? (Would the vibration be torque converter related?)

Many thanks

Dave

By overdrive, we are presuming you mean 5th gear.

Test the car again in manual mode, put it in 5th and if you yield the same results, its not the gear change (in and out of "overdrive") its the lock up clutch engaging and disengaging.
The shudder usually means the slipping of one of the clutch's, usually the TC lockup. I know that this is caused by the poor materials in the valve body in the GM boxes, I cannot be sure on the causes relating to the ZF box.

Plenty of reference material on FFRR http://www.fullfatrr.com/forum/topic...ghlight=zf+td6

Thanks very much for the reply chaybra.
It's a good point you raise on the presumption of 5th gear /overdrive being the same thing. This is probably just a terminology error on mypart. When I think about the issue more logically, it does seem to me thatfifth gear is being engaged without issue, but it's actually the locking up ofthe torque convertor that's the problem. Please forgive my ignorance (oldschool car guy), but I'm assuming these cars with all their ?fandanglery? stilluse a torque convertor like I am assuming? I'm picturing typical big bulbousstyle TC that goes on the front shaft of the transmission.
So then the question is, is this an electronicallycontrolled TC, or is it relying on pressure? It seems to me that there must besome electronics to it, as it seems to lock up based on speed (~92km/h), notRPM? Would that be a correct assumption do you think? Happy to admit I'm wrong.
I have tried your suggestion of putting the car into manualmode, and putting it into 5th gear. I still have the same problem of hunting inand out of "lock up". So, going by your point above, this means myproblem is the lock up clutch engaging and disengaging. A bit of clarificationfor me.......is the lock up clutch you mentioned, and the TC the same thing? oris the lockup clutch inside the TC?. The reason I'm asking is, will a simplereplacement of the TC fix the issue, or do I need to dig deeper inside the boxto find/fix other "clutches"?
Thanks again for the reply. The assistance is much appreciated.Transmissions are not my thing, but are on the bucket list!
Many thanks
Dave

Originally Posted by davus

Thanks very much for the reply chaybra.
It's a good point you raise on the presumption of 5th gear /overdrive being the same thing. This is probably just a terminology error on mypart. When I think about the issue more logically, it does seem to me thatfifth gear is being engaged without issue, but it's actually the locking up ofthe torque convertor that's the problem. Please forgive my ignorance (oldschool car guy), but I'm assuming these cars with all their ?fandanglery? stilluse a torque convertor like I am assuming? I'm picturing typical big bulbousstyle TC that goes on the front shaft of the transmission.
So then the question is, is this an electronicallycontrolled TC, or is it relying on pressure? It seems to me that there must besome electronics to it, as it seems to lock up based on speed (~92km/h), notRPM? Would that be a correct assumption do you think? Happy to admit I'm wrong.
I have tried your suggestion of putting the car into manualmode, and putting it into 5th gear. I still have the same problem of hunting inand out of "lock up". So, going by your point above, this means myproblem is the lock up clutch engaging and disengaging. A bit of clarificationfor me.......is the lock up clutch you mentioned, and the TC the same thing? oris the lockup clutch inside the TC?. The reason I'm asking is, will a simplereplacement of the TC fix the issue, or do I need to dig deeper inside the boxto find/fix other "clutches"?
Thanks again for the reply. The assistance is much appreciated.Transmissions are not my thing, but are on the bucket list!
Many thanks
Dave

The TC lockup clutch seems to be the culprit (presumed) this is a circular piston that engages a wet clutch pack that is built into the torque converter and (should) lock the input and the output of the TC to eliminate any slip ie, direct drive.
The fluid pressure for the clutch is controlled by a variable solenoid in the transmission control valve block that is fluctuated by the trans ECU. the speed and pressures for lockup are depended on a few different inputs. mainly speed, engine load and TPS (Throttle positions sensor). possibly more.

A common cause of failure to result in shuddering or "hunting" when the clutch should be fully engaged is the lack of hydraulic pressure on the piston inside of the TC lockup Clutch. The lack of pressure (in the GM 5l40) usually is a result in the failure of the control valve block, or (if some of the V8 owners could input here) or some sort of other internal leak past the piston itself?

the lack of pressure causes the extra slip of the clutch, intern creates a catastrophic cycle that wears the clutch creating clutch material to pass thru the system and causing the leak to get worse. its a ****ty world sometimes.

Looking at the link i posted previously, its recommended to stop driving to prevent further damage.

I would recommend draining the fluid (Go get some more before you do this) and inspect for the colour (Dark is bad - red is good) and for clutch material. if some is detected failure has already begun and next step is to pull the filter out and cut open. from there the amount of debris should indicate weather the box should be pulled or if you are lucky enough to avoided major damage and can get away with a valve rebuild/replace.

OR tank it to a auto specialist and they will be able to identify and repair quickly but costly.

Hopefully all goes well and that my advice is accurate to the ZF boxes.
Have a hunt on some of the UK forums, there is plenty of box failure posts

Thanks very much chaybra for yet another extremely informative post.

I have an update...unfortunately i dont know that its a positive one.

I was only the way home from work this afternoon and i decided to do a little more testing with manual mode. I was quite sure that previously when i tried manual mode (by selecting 5th gear) the results were the same. However it would appear as though i am wrong. This afternoon on the way home i put it in manual mode and selected 5th gear, and it actually didnt have the issue. It didnt actually lock the convertor at all......and didnt try.

However then things changed. As i was driving along with the car in "manual" 5th gear, it hesitated ever so slightly. I heard a chime from the dash and the mesage "trans failsafe mode" popped up. The car stayed in 4th gear. Luckily i was literally 30 seconds from home so i coasted home, parked it and left it.

So thats where things are at now. I dont really know if that helps the issue at all (troubleshooting), or wether it means something else has gone wrong.

It might be time to perhaps buy some diagnostic software for it.

Any ideas?........getting to the end of the tether!.

Cheers

Dave