I'm having trouble with my steering clutches releasing on this 48A4850. I've changed the filters under the seat and under the floor plate and drained and refilled the trans and steering clutch compartments with Cat 30W Trans oil. The oil was black when I changed it like motor oil was getting in but I don't seem to be losing engine oil. Every day, sometimes more than once the pump will evidently lose its prime. You can take the plug out of the top and turn the engine over until oil pumps out and replace the plug and it will steer great. Before I thought of priming the pump, the steering levers never had any spring pressure to them when you pulled on them. What I mean is that if you went up a steep slope you had to hold them forward or they would slide backward and disengage the clutches. Ever since I primed that pump the first time, the steering levers have a good amount of spring pressure to them and it steers better than some D7G's that I've run. By the way, I replaced the trans pump back in March. I also put a pressure guage on the trans pump when I started having trouble and I only had 40 lbs pressure. That's when I primed it the first time. I only had a 160 lb gauge and it was maxed out after that. I know the pressure should be around 275 lbs according to the book at the clutches to release them. I never measured it again with the correct gauge because it steered so good after that. But now my new oil is getting black again after about 10 days usage. Is it burning the oil because it could be starving the pump? It seems like it only loses it prime when you are parked on a slope waiting for the next scraper. I have already put new filters in it again with no effect. It doesn't seem to affect the transmission function at all. Is it my scavenger pump or could it be getting air from somewhere?

Don, Black oil is most likely from the engine oil blowing past the rear crank seal, if you had burnt oil you would have torque over heating and you could smell the burnt oil. It would be brown not black.
I think you should check the trans pump suction line for a leak, pump may sound like it has marbles running around in it.
You replaced a trans pump??? was the back plate milled out behind the drive gear???
If so check the new pump, it may be ruined too if the drive gear has worn splines. Worn splines will force the drive gear on the new pump back into the back housing.
Come on back with what you find.
Later Bob

I don't hear any noise from the pump at all. I'm not sure I understand about the back plate being milled, I just pulled the old one off and put the new one back on. I will tell you the reason I had to replace it was that I had the floor plate up and I decided to check that filter for the first time since I've owned it. Well, it was full of trash and I cleaned the housing out completely and put a new filter in it, but I didn't put oil back in it and the pump ran dry and locked up.
I've got the belly pan off now so I'll check the suction line. Surely I didn't leave one of those blue rags stuffed into the suction line when I changed that pump...

d9gdon give me call i mite have the answer to your proble.we have two D7 E &F we have had simiar proble.you can call me at 916 929 7773 I im in California.Jason

It could be the seals that feed the release pistons in the bevel gear steer clutch compartment, or leakage around the pistons as well. You need to get a pressure gauge and check at the manifolds under the fuel tank. If pressure bleeds off on release then you have a leak.

Thanks Jason, I'll do that.

Bob, are you talking about the big teflon seals? Are you saying I'll have something like 275 lbs pressure when operating and if my pressure drops when I release the clutch(es), that would indicate bad teflon seals in the pistons?

I still haven't had time to check the supply side of the pump.

I think Bob means the teflon rings on the inner steering clutch flanges, inside the bearing cages. They go out if you lose the bevelgear shaft bearings. I think you have an air leak caused by taking the line off the old pump and moving it. A rag in the line wouldn't clear up by bleeding air. Steering levers falling back is strange, only thing they work against are the springs in the valve.
Later Bob

Thanks bob, I'm going to look into it first thing tomorrow. It quit again today and was really hard to get primed again. I'm preoccupied with a 627 apron cylinder with 3 updates on the cylinder kit and 2 strikes against the dealer.

Thanks for the help on this, the service manual only goes so far...

Jason, I tried to call but no answer. Thanks in advance if you can share it on here.

I found it. All it turned out to be was the suction line on the bottom of the pump had come loose and was sucking air. It works as good as new. Thanks for all the help.

That was to easy:) Got to have one of those every once in awhile.