Good morning.I’ve been a long time lurker but haven’t posted much at all. I have a Komatsu D20a (sn#45119) that’s a mid to late 80’s model. In the last month or so , the steering and ability to back up had gone away with one exception. It does “ok” when the dozer is pointed up hill and the fluid is to the back of the machine . If it’s on an incline it steers good but not great. The clutch oil is fresh. It has IW32 in it. Everything I’ve read says that’s the equivalent to SAE 10wt. Also, I pulled the strainer and it had some junk on it but not terrible. I’m leaning towards the clutch pump (haven’t tested) , since that’s the piece of equipment the steering and drive clutch share . Anything that I’m missing? All fluids and filters are fresh within the last few months. I do notice that when I’m on flat ground I can press the clutch foot pedal and that side track will relax . I’ve adjusted brakes, linkages, etc. I posted this in the large thread on the 20/21’s as well but haven’t got any responses yet.
Sounds like a suction line if it working alright pointing up hill
I appreciate the reply. A suction line in the clutch housing? The pump is mounted in the clutch case .
Pump seems to pump ok when its at its hardest for the machine to work when the oil is at the back of the dozer . Pick up will be in the transmission , is the transmission oil full of bubbles ?
I will run it tomorrow and see. So there is a pick up for the transmission in the clutch housing? Just want to make sure I understand.
Is this lever or pedal steering ?
Pedal steering
Pick up to the pump comes from the transmission , there are 2 lines coming from the top that go to the pump . I can't see any lines from the clutch housing (clutch oil ) returning oil from there to the transmission
https://k-part.777parts.org/catalog/komatsu/d20a-5c/090110/ This shows the lines to the pump , all the joins need to be checked and for damage enough to let in air on the suction one