I have a 2011 JCB 4cx that was working fine one day, then the next started having shifting problems. It has the 6 speed transmission, and it will go into gear fine, but as you are moving and give it full throttle it will kick out of gear and act like it goes into neutral or something starts slipping. This happens in all gears, 1st, 2nd, 3rd and Auto. When the rpms are lowered back down it will go into the selected gear fine. When i put the bucket and standards down to raise the wheels off the ground so there is no resistance , the transmission works fine and shifts through all gears flawlessly. The kick down button is free and seems to work, and all fluids are good. This machine only has 250 hrs. on it. Any help is greatly appreciated.
Check the suction screen on the bottom of the trans
As d4c24a said check screen in the bottom of box the oval shaped one two bolts 1/2 " or 13 mm depends where you from I guess see if oil is burnt but make sure you have a clean drain tray think it about 21 ltrs of oil and see what comes out and if any thing is stuck to the screen . Does the trans oil pressure switch work?
u can easily solve your problem with the help of repair manual. U can download the repair manual from http://www.reliable-store.com/ or http://www.reliable-store.com/pages/search-results?q=jcb 4cx&p=1