SkyTrak 10054 with ZF transmission

[aerolift]

SkyTrak 10054 (2006) with ZF transmission...
Has 1,2,3,4 gears in reverse.
Only has 4th gear in forward.
Have replaced shifter and cab harness.
Removed & replaced diode packs.
All connections and wire loom are clean and unbroken.
ISZ, others, any thoughts??

[icestationzebra]

I think this has a WG98. I couldn't find a service manual on the JLG website but there is one for the Lull 1044B-II which also has a WG98. Unfortunately the small section on shift logic is not very clear.

There are 6 coils and I believe the speed gear logic is the same wether you are in forward or reverse. You can determine if it is electrical or mechanical by checking the coils for power. And the quick way is to use a screwdriver to see if the coils are being magnetized. (Just make sure not to run yourself over!) Go through each gear in reverse and touch the top of each coil with a metal screw driver. If you fell a slight tug it is on. Note which coils are on. Then switch to forward and go through each gear again. One coil should always be on in forward. A different one should be on in reverse. One should be on in 1st, another for 2nd, and so forth. You should see something like the table below - I just don't know which coils are which. If you see this than something mechanically is wrong. If you don't something electrical is wrong.



ISZ

[aerolift]

Thanks, ISZ.
It is WG 98. We replaced the coils and retested. Each time with the same result.
We contacted a Palmer Johnson and talked to a service rep.
The conclusion is the forward clutch pack controls the 1,2,3 forward gears and therefore has failed.
We are in the SkyTrak salvage business and have that transmission in stock.
It is easier to R & R the trans than to pull it, split it open and replace the damaged clutch pack.
The switch is scheduled for today. We will flush the system and refill.
I'll respond to the forum with results, when they are known.

[aerolift]

Success!!
We pulled the trans and replaced it with one we had salvaged from a previous teardown.
Flushed the old oil and replaced it. Connected all the hosed, wires and secured the trans and drive shafts.
Started the engine and, with great relief, watched it respond in all gears, forward and reverse.
I'm very proud of my men (who happen to be my sons and a close friend/employee).
They were very professional throughout this complex diagnosis & repair.
Thanks, ISZ and Palmer Johnson for expert guidance.