Deere 855 rear binding?

[WinterDeere]

So, I was making a tight turn with my new-to-me 855 on asphalt, in 2wd. The machine started to buck a little, as if it was in 4wd, or had some issue with a binding rear. I thought I could hear the rear tires slipping a little in the process. Machine has a model 52 FEL, but there was nothing in the bucket at the time.

I've spent several days at the controls of a Deere 750 with FEL, but other than that, I'm all new to Deere CUT's. So, there are several obvious questions:

1. Is this normal for an 855?
2. Any possibility the diff lock is dragging? Is this a locking pin or a friction disc type setup?
3. Any possibility the machine is still in 4wd when the lever is set to 2wd? How to check?
4. Is my rear (or front) diff messed up?

Thanks, guys!

 

[Mechanos]

You can check to see if the front axle is engaged by placing the bucket flat on the ground, then lifting the front end off the ground. Curl the bucket slightly up so the cutting edge doesn't bite in and drive forward. If the front wheels (or at least one of them) is turning, the front axle is still engaged.

The diff lock is a pin type. When you use the diff lock, it will often stage engaged as long as you're applying torque to the drive gears. After your you lift your heel off the diff lock lever, you might need to roll backward slightly to allow the diff lock to disengage.

Another test would be to put the whole tractor up on jack stands with all four tires off the ground. Push down on the forward drive pedal and see if the front tires are turning. Also, while the rear wheels are turning, step down on one of the turning brake pedals. If the diff lock is not engage, that rear tire will stop and the other wheel will keep turning. If the diff lock is engage, you will hear the HST complain when you step on the turning brake.

 

[Rock knocker]

1. Is this normal for an 855?
2. Any possibility the diff lock is dragging? Is this a locking pin or a friction disc type setup?
3. Any possibility the machine is still in 4wd when the lever is set to 2wd? How to check?
4. Is my rear (or front) diff messed up?

I have a 950, but:
1) I would think not. In 2wd, it should drive like a car with a open diff
2) That's where my money is
3) Possible. Jack the front end up with the FEL, with the tranny locked. If:
a: The tires rotate in opposte directions, the diff is OK
b: The tires rotate in the same direction would indicate that the front diff is locked. This shouldn't be possible on your unit
c: The tires do not rotate, indicates that the machine is in 4wd
d: You could also do a single front tire. It should rotate freely when the tractor is in 2wd.