Machine had been running great. Started noticing a loss in power. Checked the transmission and there was air in the oil. Soon after the back hoe wouldn't move forward or back and the parking brake would not shut off. The transmission oil level was good when I checked it at start up but developed air in oil within a minute or two. It will still move at first but then not at all. Any ideas as to what the cause could be? I have not added oil or changed oil anytime recently. The oil level had been good and the backhoe had been running great prior to this issue.
Hey, welcome to HEF! Posting your serial # might help find the problem. How many hours on machine? Air/bubbles in the trans oil can certainly rob the transmission of the ability to do work. The root cause of aeration of the oil can be tough to diagnose. There is a vent on top of the transmission, make sure it's clear and not covered with mud or dirt. Check trans fluid level. Hard to check, but if pickup screen is loaded with clutch friction material, that can cause your problem. The transmission pump is powerful and if pickup screen is loaded up with debris, the pump can actually pull air around the o-rings where the pump is mounted causing those pesky air bubbles.
Please post a machine serial number. There are 2 different transmissions for that model backhoe, and they are very different.
I cleaned off the transmission, but did not find a vent, and added some transmission oil. I fired it up and the oil airiation had reduced enough to get a read on the dip stick. The oil level was low maybe from pushing up the tube when it was airiating, there was no sign of a leak. The transmission is working properly again but is still low on oil. I am out of transmission oil and ordered some more. I'll do an update when I get more oil and give the machine a test workout.