I have recently replaced a transmission in a 90L series machine (with a Caterpillar tested and passed transmission) which is operating in hot conditions and when the oil gets to operating temperature the machine stops driving. Where do we start to look to fix it.
If you just installed a rebuilt HPCU you problem might be the drive motors. You need to get an inline flow meter and install in the cooler line at top of cooler, lock brakes and stall it hard untill warm 175 deg F( stall in and out not steady ) record cooler flow at stall. If you have les than 16 GPM you will have overheating problems. To Determine if Loop Loss is pump or motor, block the pump outlet and retest, the increase in cooler flow is the motor loss. Later Bob
Those things carry 70 L in the hydrostatic drive 5 in the pump drive and no, oil no go especially as they get hot. Bob is probably right in all the above but,check the oil levels, because maybe it is just a leak.