1985 jcb 3cx no forward or reverse

hi,i am new to this and I don't know if any one can shine any light on a problem with 1985 3cx no 313610, i have been using this machine for 6 month with no problem but now it will not go forward or back, the problem started when using the dump clutch pedal, also i can not select the gears easy in neutral , some times it trying to go but with no power or very little to the back wheels, oils are all good, the transmission is the type with filter in the sump in the gear box and the f/r shuffle lever on the left i think its the b/w gear box no 13027/585/3180 if this helps, hope you can help as i would love to get the old girl sorted, any help from any one would be very grateful, regards and many thanks martin

If yours has the Borg Warner shuttle the clutch cut out is operated by a mechanical linkage,secure the machine,go under it in front of the left back wheel,look up at where the F/R cable connects to the shuttle,have a second person in the seat to operate the dump valve and you will see it push the valve in,the valve is spring loader to return and there should be .010" clearance between the valve and the plate that pushes it,to adjust the clearance loosen the jam nut on the bolt that screws into the valve,screw the bolt it in or out to get the right clearance,make sure all the linkage is free,give that a try and see how it goes.
AJ
Ps forgot about the gear change,that 4 speed box has its own oil,80W 90 gear oil,make sure the parking brake is releasing and the main brakes are free.

hi aj, thanks for your reply. You are a godsend to us kind of blokes. I was reading some of your previous forums from 2006-2009 regarding someone having a similar problem. I read up on this in the early hours of the morning, printed off some of your forum sheets, went out this morning and tried this before reading this forum and got the old girl working. One question when my dump pedal is depressed my valve comes out of the box on the dump valve and when released it pushes the rod on the dump valve in. How I achieved approximately 10 thou clearance was pressing the rod in the middle of the dump valve as far as I could in by hand then adjusted the nut on the valve rod to approximately 10 thou so I could just rattle it when the pedal was up and the rod was in the box at its furthest point. On depressing it it lets the valve rod come of out the box to drop the torque converter pressure but the valve rod seems to work the opposite way dropping pressure when the valve rod protrudes out of box is this correct in my understanding? On the point of 80/90 EP oil the gearbox is obviously the part that sits behind the box with the oil pan on with a level plug on the side where you fill it to. I have now got about 70% forward and reverse push power I am not sure that it is delivering the correct amount of power as today I was using the machine with the four in one bucket open grading back in second gear on a little bit of soft ground and once it had a slight amount on the bucket it really did not want to pull anymore it was not wheelspinning I had to go down into first to do this job it seems a little under powered I wondered if there is any other adjustment I can do to increase the power. when i say power i do not mean engine power but gear box torque

Regards

Martin

I got things the wrong way round,it should have 10t clearance when the pedal is pressed.if you have the manual it will tell you how to test the pressures and do a stall test,the adjustment of that valve is the only adjustment that can be made on that unit.
AJ

hi aj, i have tried to find a manual but with no luck, I have worked the machine for about four hours today and it definitely seems under power to what it was. I did not quite understand what you meant about the adjustment do you mean the clearance between the mechanism that releases the valve and the valve pin when the dump pedal is up. Mine when the pedal is up I can press the valve pin in by hand as it feels like it is sprung loaded against the mechanism and I can gain roughly 10 thou movement away from the mechanism into the box would this be correct?

Regards

Martin

hi aj, i have tried to find a manual but with no luck, I have worked the machine for about four hours today and it definitely seems under power to what it was. I did not quite understand what you meant about the adjustment do you mean the clearance between the mechanism that releases the valve and the valve pin when the dump pedal is up. Mine when the pedal is up I can press the valve pin in by hand as it feels like it is sprung loaded against the mechanism and I can gain roughly 10 thou movement away from the mechanism into the box would this be correct?

Regards

Martin

Push the valve in fully and secure/jam it there to test the function,if that no good try it with the valve out,watch Ebay for a manual or Tradebit.com.
AJ

I HAVE A JCB 1400B THAT HAS LOST REVERSE & FORWARD. DOES ANYONE KNOW WHAT THE LIGHT MEANS THAT LOOKS LIKE A GEAR WITH AN OIL DROP UPON IT. I DO NOT HAVE A REPAIR MANUAL TO LOOK IT UP. ANY IDEAS?

If your machine has the Borg Warner Velvet shift shuttle with a manual shift and clutch cutout that the valve needs adjusting, the light is for the shuttle oil temperature,check the oil level with the engine running on low idle,the gearbox in fourth gear,the shuttle in neutral.if the level is good check that the lines going to and from the cooler are not kinked or squashed,see the cooler is not blocked,get a second person in the seat and go underneath in front of the left back wheel,look up at the side of the shuttle and get the helper to move the F/R lever so you can see if its moving the valve and press the clutch cutout pedal,you will see the lever moving away from the valve and the valve plunger coming out,when the plunger is out drive is disengaged,it is spring loaded to disengage,when the pedal is released the linkage should push the plunger back in to within .010" of bottoming,there is a bolt with a jam nut screwed into the plunger to set the adjustment,first jam the plunger all the way in to see if drive is restored,do not use force,there can be other causes,torque,pump,etc.
AJ