Skytrak 8042 Hydraulic problem. (De-clutch)

[mdraper]

What ended up being the solution. I have one with the same issue. Drive cuts in and out but seems to work consistently while using the boom lift/lower functions. The declutch has been inspected. fluids and screen are all ok. followed the hose on the declutch to the pressure reducing valve under the cab. was going to start checking hydraulic pressures from there but figured id check here first. Any help would be great.

Serial # is prior to SN 9909. Unit has a Clark Transmisson.

 

[Skytrak Jake]

The forklift has been unoperational for a while. I had a pump failure. I just finished replacing the main hydraulic pump/ re-sealing the cylinders and replacing a few rods. I just finished purging the air out of the cylinders and new lines yesterday. But to answer your question i still have the de clutch problem. after talking with a few people about this issue. The first thing i will try is to monitor the declutch pressure with my test gauge. It seems to be leakage on the de clutch circuit causing the issue. If that is the case it will be a valve rebuild job. But i have not tested it yet, its just the next step.

 

[mdraper]

Thanks for the update. The conclusion ive come to is that the valve that is in the manifold under the cab is passing oil. When the park brake switch is in the off position, i have about 60 PSI supplied to the de-clutch and i believe that number should be 0psi. When i went to order the valve assembly, part #8036243, it shows discontinued. For the time being i just put a cap on the hose that goes to the de-clutch. Only change ive noticed so far is that the machine will go into gear with the park brake engaged. So ill have to pay more attention to that so that i don't drive through the brake.

 

[skyking1]

As I recall about those machines, there is a dash switch that selects declutch with brake application. That lets you rev up the engine while stepping on the brake to lift the boom quickly, etc. without putting it in neutral.
Perhaps the switch or brake sensor is malfunctioning and commanding a declutch?