Interceptor
Member
The gearbox is vented to relieve any pressure caused by temperature changes. Any significant pressure in the gearbox would indicate a blocked vent. That could be the cause of the oil leak at the axle, but wouldn't cause the drive issue. High oil level in the gearbox would indicate either a brake piston leak, or a motor shaft seal leak. Either one of these would also put some pressure into the gearbox, but it should immediately be released out the vent. There is a breather at the top of the gearbox, make sure it's not blocked.
If one or both brake pistons are leaking, the oil level in the gearbox will gradually increase whenever the brake is released (when driving). I can't say for sure how fast it would rise, it would depend on the severity of the leak.
I think a charge pressure test is a good next step. If that checks out I'd test drive loop pressure. Have you tried to run it with all four wheels off the ground?
If one or both brake pistons are leaking, the oil level in the gearbox will gradually increase whenever the brake is released (when driving). I can't say for sure how fast it would rise, it would depend on the severity of the leak.
I think a charge pressure test is a good next step. If that checks out I'd test drive loop pressure. Have you tried to run it with all four wheels off the ground?