Checking the internal leakage of the drive motors isn't difficult, have to have a couple of things though to keep it from being a messy job. There are two small lines going to each drive motor. One is for the high speed drive, the other is the motor case drain. You have to deterimine which line is the case drain and which one is the high speed drive control line.
First of all, be very cautious performing these procedures. The will require the engine running and the safety lever in the operate position while working on the machine.
Once you've determined which line is which, you remove the case drain line from a drive motor, and you'll need the proper plug fitting to block the disconnected line, else you'll have a constant flow of oil from the line. Find some type of hose that will fit over case drain fitting still on drive motor and send the hose to a bucket or drain pan. Swing digging bucket over the track that you're testing and use the boom/bucket to lift that track off the ground. Operate the drive for that side and monitor how much oil comes out of the case drain fitting. I can't remember the acceptable leakage amount, but I'd say if you're getting more than a 1/2 gal to 1 gal per minute out of that drain, may have a failed drive motor. Check motor on other track in same manner.
You can also test if high speed drive is getting pressure at the drive motor by removing the line that connects to the high speed control fitting on the motor and send that line to a drain pan. Start engine and place safety lever in operate position, then select high speed drive. This should activate solenoid at the pump and make oil pressure come out of the line you have placed in the drain pan.
