277b won’t move

My Caterpillar 277b serial number MDH 04693 won’t move. Yesterday it made a clanking noise from the area of the right drive motor and balked at moving. It eventually moved and I used it for an hour without a problem. Today it stopped and started and eventually stopped altogether. The hydraulics for the bucket still work. Now there is hydraulic fluid leaking from the right drive motor and I found a small piece of curly q (about an inch long) on the track under the motor. The sprocket bearing is pretty new and it wasn’t hot. There was no screeching noises.