[NYCub]

Hello all - I hope everyone is safe and sound.
As I mentioned in my introductory post, I've recently picked up a 127 for my mother who can't push the foot pedals on her JD any more. I bought the tractor sight unseen - knowing that there would be some problems (battery, points, steering slop, bad fuel, etc). However, I didn't anticipate a very loose differential. On a flat, smooth concrete floor, I can't turn in reverse! One tire just spins. I can't back up in grass either. Again, one just spins. It seems ok in forward. My first thought was the fluid - and low and behold, it wasn't low, however it wasn't red and didn't smell "right". It looks like someone filled it with engine oil or something like that. I don't have a IH Case dealer anywhere near me, so I'm going to flush and refill with something like Traveler to see if there is an improvement while I source Hy-Tran.
If anyone has other ideas, I'd love to hear them! Can the diff loosen up?