Machine is standard shift with shuttle f/r. s/n FDP 08810. I think an '02. I use it on a small cattle farm. Good machine, lots of power, easy to operate. It started out slipping out of forward once it got warm then it wouldn't take forward. I found a loose screw in the f/r selector switch (from an earlier thread a member had posted here here on HEF). The slipping out of gear stopped but it still won't take forward after it warms up. Works fine in reverse all time, takes all gears. Once warm (about 15 minutes) it wont take any forward gear. Any ideas or information greatly appreciated.
I've found an almost identical symptom, ended up finding a faulty modulation clutch on the transmission. I'll see what info I can find when i get home tonight.
So I missed the bit about standard shift sorry.... no modulation clutch solenoids, just a solenoid control valve with a REV and FORWARD solenoid... First thing that comes to mind, find these solenoids and swap em.
Could be most anything in the forward/ reverse circuit, but I'd bet its the electronic shift box on the selector. They are know for that problem.
On second thoughts, might be easier to swap the wiring to the solenoids first. If the fault moves, you know the problem's upstream in the electrics somewhere as grandpa suggested. Just be careful operating it with the controls reversed.
Thanks Chrisso and grandpa for the replies. I will swap solenoid wiring at the connectors and see what we get.
Couldn't swap wiring, it has two different connectors. I did swap the solenoids. Now when I shift reverse I get forward travel but when I shift forward I get nothing. Would that indicate faulty solenoid?
Are you getting power to the suspect solenoid?
Honestly I can't see why those solenoids should be different p/n's... I mean you're right they are... but I suspect they're just the same solenoid with a different plug on the end for safety. Pretty sure you're going to have to be in the cab with park brake off to check for power, but could be wrong. Definitely worth trying. If all else fails, put the solenoids back and swap the plugs over with the wiring... Let us know if you need a copy of the schematic.
If anything it indicates the problem is the solenoid or anything else upstream (ie you're transmission is good). If you can swap the solenoids and wiring indepently as above you could rule out the solenoids too.
I returned the solenoids to their original positions. Each one reads 8.1 ohms resistance. The reverse solenoid wiring reads 12.4 volts but the wiring for the forward solenoid reads 3 to 3.8 volts, it is not steady. I also swapped the wiring at the solenoid connectors. Now when reverse is selected it travels forward and when forward is selected, I get nothing. Is there anything else in the frw/rev circuit, besides the f/r selector, that would prevent one solenoid from engaging?
I bought a fwd/rev switch from Cat yesterday, got it on this morning and that solved the problem. Thanks Chrisso for the troubleshooting help and grandpa for the diagnosis. Your knowledge and willingness to share information is greatly appreciated.
No problem glad you got it sorted
Had to replace the one on our 420DIT as well for the same problem. Glad you got it fixed vcat.
Im glad you got it going.