580SE no front 4WD

I'm looking at an older SE for sale with approx. 7000 hrs. There is power to the front driveshaft in 4WD but no power at the wheels . You can rotate the front driveshaft freely with the machine on the ground in 2WD. Something is obviously broken in the front diff but there's no ugly noises that I can hear. Any ideas on how serious of a problem this could be? The owner is willing to discount the price substantially but I don't want to get into a full-on overhaul.

Did you see if the u-joints were turning in the steering joints, have the planetary covers looked like they have been off lately on the front wheels. It could be a stripped input shaft yoke, stripped pinion splines, ring and pinion, rt/lt axle shaft from the diff, sun gear in planetary stripped or removed. I would look close at the pinion input splines and drive shaft yoke, then spin the drive shaft again and see if the u-joints are turning, leave it in 4x4 and raise the two front tires off the ground and try to spin the tires by hand and watch the u-joints in the wheel. Some of those parts are pretty high. Other things to think about, does it have a full cab, extenda-hoe, 4x1 bucket, some of these options are a trade off when looking at a repair cost and getting a deal with a machine. If your not hearing any noise you could pull the drive shaft and sun gears and run it like it is also and fix issues with it later. Did you check the drain plug in the axle and planetary lube levels, see any metal on the mag, oil look ok.

I will investigate further and try all the suggestions you listed. This machine does have a full cab, regular bucket and a 40" Dutchman Tree Spade in place of the hoe. The spade is worth $9000 on its own but without 4WD I will be stuck all the time with the type of work I will be doing so the 4WD is mandatory. The tires are all in need of replacement also and I'm not too sure if it's worth putting on new tires for another 2000 hrs. worth of life expectancy. What do you mean by your comment "Some of those parts are pretty high"?

How much use would you have with a tree remover? Will you not need the hoe end ?

We already have another backhoe and an excavator and we were really only looking for a tree spade. Most of the decent used tree spades I have seen are around $8-10K. This backhoe with spade came on the market with an asking price of 12K before the front 4WD broke. Now the price will drop- just how much I will offer is depending on how serious and expensive the repairs could be. I think a used front axle complete is around $4500?

That's a good looking rig the way they have it hooked up. You are right about the $4500 for a complete axle. The ring and pinion is around $1500.00, long axle shafts $700.00, short shafts $350.00, sun gear $130.00, Front input flange $260.00, other parts, seals, bearings, and so on. Just need to pin point the issue, and talk to the owner, I would not think he would buy the $4500 number when it could be a $500.00 to $1000.00 repair also. He could also change his mind, fix himself and hold his price.

Is that oil leaking at the rear end (under the hydraulic manifold), or did you spray it with water?

The owner took the photo not me. I sure hope it's just from the pressure washer, otherwise that's a pretty bad leak! When I tested the rig, there was really no leaks. What would it cost to replace all the rubber on a rig like this?