1970 c20 starter problem?

[paulbrgr9999]

Had a scary moment out in the desert this past weekend. I parked my truck on a mostly level surface while pulling my toyhauler and turned off the motor (350). Got back in the truck after about 2 minutes and turned the ignition key to start. The truck made a noise that sounded exactly like the sound you would hear if the motor was already running. A loud screeching. I tried the ignition twice more with the same result. Loud screeching. But the engine was not already running. So I got out of truck crawled underneath and looked at where the starter engages with the flywheel. Everything looked fine (I dont have the dust cover on). So I got back in the truck and moved the shifter (turbohydramatic) from park to 1st gear and back and just kind of rocked the entire truck back and forth. And then when I turned the key to start it fired right up like normal. This truck has never done this before and its now starting everytime with no problem (probably 20 more starts since this episode).

is my starter about to go bad or?

I dont want to get stuck in the middle of no where.

Ant opinions or ideas are welcomed

paul