I have a RS6-42 that does not want to go into gear, forward or reverse. We had the same issue with it not wanting to accelerate awhile back and messing around with the wiring harness at the ECU seemed to fix that issue. If you sit there and shift it back and forth for awhile it will go into gear and run fine until you shut it off and leave it overnight and the problem arises again. Ive got it in the shop now and the mechanic has changed all the fluids and tells me there is no "pressure". Im not a diesel mechanic so i dont know what that means exactly. Hes saying he needs to pull the transmission to inspect it but im having a hard time believing its that deep knowing that it does go into gear, moves and runs just fine once it finally decides to do so. Has anyone else ever ran into this problem.
I think you're on the right track when you talked about it being electrical. have you gone through the harness to see any shorts to ground?
Have you checked the ground on the transmission control unit? That would cause all kinds of grief.
A serial number may help. I'm going to look like I don't know anything but I looked up your machine and it appears to be a Gehl? I looked at a parts book and it looks like it has an 11000 series Clark transmission. I'm 99% sure you have a power going to the shifter problem. Some Lulls had them. There may be a pressure switch not closing to send power. You need a lest light and volt meter and start chasing. There may be a relay feeding the shifter that's dirty and not passing current. If when it finally starts working it has all gears and ranges there shouldn't be any mechanical issue with your transmission or shifter.
Any of these issues I think would be more common than ripping into a transmission for no reason. Sounds like the shop just needs a few more billable hours smh. Either that or the mechinic doesnt want to dive into electrical chasing. Im waiting on a service manual to show up and i may give him one more chance to find something wrong then im picking it up.
When you say "messing around with the wiring harness at the ECU seemed to fix that issue" are you talking about the actual engine ECU, or the F-N-R Shift Module for the transmission (which should be under the panel with the load charts)? I'd be checking for proper voltage signal from the shifter, since their contacts can get pretty dirty and worn out, IIRC. Like everyone else, I'm inclined to agree it sounds like an electrical control issue.
No im talking about the engine ECU located back by the turbo. Messing with it now doesnt resolve the issue with it not wanting to go into gear now. I need to look at the FNR Module. Like I said, not very familiar with this machine yet. I know it a connection issue, or corroded wiring somewhere.
Do your brake lights go off when the park brake switch is cycled? The trans will not go into gear if the park brake is still engaged. There is likely a module located somewhere around the operators station that controls that system.
Yes, there is a little green light that indicates if the park brake is activated or not. It does turn off when switched. Done checked that out, one of my first thoughts too.