ZF Auto Issues Help Needed?

[Skiboy]

I have a ZF auto from a disco in a RR hybrid that is havingissue I think. History of the Auto unknown.

Symptoms:
Harsh gear changes and holds until high revs
Revs high before changing gears or needs accelerator back off to get it to change (not foot to floor - even from slight accelerator)
There is a vibration once revs build a little - like a pulsing or shuddering vibration that seems to be transmission
Transmission oil at right level and not getting hot (I havea temp gauge in the cooler line).

Any suggestions on what might be wrong - any symptoms I could look for to help diagnose the issue?

I can't say I am looking forward to pulling this auto as itis the second one in there.

Skiboy

[PhilipA]

Check that the kick down cable is not sticking in the "open" position.
Sometimes because of age or near the exhaust they are pulled open by the accelerator and do not return.
That would explain your symptoms as mine used to do this when I had to jury rig a kick down linkage on a Thor manifold.
Regards Philip A

[Skiboy]

Thanks Philip I did wonder about that - I will look at it tonight.

Mine is connected to the accelerator mechanism for a series 3/stage one (the body that we used) - so it is definitely not standard. Might look at the RR Ute and see how much travel a kick down cable SHOULD have.

I had to modify the linkage we had to take the auto kick down so I wonder if I have too much travel too early in the pedal movement????

I guess I could disconnect the cable and see how it runs - that way I will know if it is the cable (jamming or travel) or the box.

This still leaves me wondering what would cause the shudder? I have seen a post talking about a product called Dr Tranny that fixed torque converted shudder. Not found where to buy any of this in QLD yet.

Skiboy

[Tank]

The Kickdown Cable needs to be adjusted to LR specs, as it controls the Oil pressure in the box.
I can't remember the correct adjustment, but there is a small metal ball crimped to the cable between the (threaded) end of the outer cable and the yoke on the end of the cable.
This ball needs to be adjusted to about 1/8" from the end of the outer cable.
In other words some pressure should be on the cable, I broke a cable once, I pulled the broken end out and wrapped some wire around the cable and the end of the outer and it got me home all right, LR Manual should have the procedure or the Rave disk, good luck, Regards Frank.









Thanks Philip I did wonder about that - I will look at it tonight.

Mine is connected to the accelerator mechanism for a series 3/stage one (the body that we used) - so it is definitely not standard. Might look at the RR Ute and see how much travel a kick down cable SHOULD have.

I had to modify the linkage we had to take the auto kick down so I wonder if I have too much travel too early in the pedal movement????

I guess I could disconnect the cable and see how it runs - that way I will know if it is the cable (jamming or travel) or the box.

This still leaves me wondering what would cause the shudder? I have seen a post talking about a product called Dr Tranny that fixed torque converted shudder. Not found where to buy any of this in QLD yet.

Skiboy

[PhilipA]

Mine is connected to the accelerator mechanism for a series 3/stage one (the body that we used) - so it is definitely not standard. Might look at the RR Ute and see how much travel a kick down cable SHOULD have.



Just remember that there is a sort of stop as it reaches kickdown and it has to pull through there to get kickdown.
Its a delicate balancing act and I had to make 3 levers to get the correct length for the lever. As long as the lever has only a small bit of preload at idle AFAIR about 3MM from the lead crimp to the outer then it should work properly.

Regards Philip A

[Skiboy]

Thanks Guys

I am not 100% convinced it is the kick down - I did put a bit of time into this when first set it up. But truck not running then so limited testing. I think I compared it to the RR Ute but also tested the kick down point by hand pulling the cable.

The gear changes are very clunky so I do wonder if it is not something in the box?

But I will try and elminate the kick down as the issue first.

[damienb]

Check the throttle module in the valve block first (after checking kickdown)

Then the governor. It sounds like this.

Both are with the box still in the car. The first is about an hours work. The second is transfer case off.

[Skiboy]

If it is the governor then possible due to shifting debris I had read somewhere - ie after changing filter and oil (which we did when it went in)

If I get to the stage of taking transfer off I would simply put in a different Auto off the parts shelf in the shed

I would get it tested first - can they do bench test on these before they are installed?

Skiboy

[PhilipA]

I am not 100% convinced it is the kick down

Looking at the possibilities the next most likely IMHO is the governor sticking BUT this usually is only the first change of the morning.

Other common ones are inverted 1st gear clutch and then it will not start in first but will if you manually select first.

Regards Philip A

[Skiboy]

Hey Philip none of those symptoms.

First gear fine and first gear change not too bad then it gets worse for second to third (can be quite difficult to get it to change up and clunky as drops into gear) and very clunky to OD and then only if take foot comepletely off the accelerator.

Whole time there is a shudder that gets worse as revs build - feels like the torque converter shuddering.

Skiboy

[sierrafery]

Might worth a try with this one Dr. Tranny Instant Shudder Fixx (http://www.lubegard.com/~/C-250/Dr.+Tranny+Instant+Shudder+Fixx) , made miracles on a friend's D1(which afaik has the same ZF autobox like the RR) ... maybe you find a supplier down under

[Skiboy]

Been trying for 2 days to register on a site that supplies Dr Tranny locally in Brisbane - can't seem to get the registration process to work - in email with them today.

May well try this option first as cheap and not involve taking a box out.

But I have this feeling I am going to be refitting a new box - lucky I have 2 on the shelf - I just need to see if there is a way to test which box is best.

This will be the 2nd time a box has gone into this build so I am not happy (we use jacks and stands no hoist in my carport!) - so this is all done the hard way!

So I have these steps in mind

Adjust kickdown and see if it is hanging the box because too tight (checking my mechanism at accelerator cable in process)
Add some Dr Tranny to see if frees up shudder/gear changes
Take truck to auto place for a professional verdict
If current box needs lots of fixing then arrange auto place to test other boxes and torque converters that I have
I will then install best of what have back in the truck
Skiboy