Long time lurker and first time poster. We have a JCB 3CX Loader/backhoe with 1350hrs that gets occasional use on farm here in Australia. Due to the size of the operation this machine when used may have to do some road miles in top gear. After 15-20 mins of top gear at around 2100rpm the trans temp light and buzzer sound and will not go off until machine has been shut off and cooled down for some time. All fluid levels and coolers are good, machine operates and moves fine and is only low hrs. Just wondering if this can be an issue and what to look for(no dealers where we are) and by the way ambient temp makes no difference. Mike.
Check the cooler hoses to gearbox if they have been connected the wrong way the transaction does not get cooled very well. The torque converter out should enter the cooler against' the flow of coolant if that makes sense if not swap hose on trans cooler and try it