Early Variable and Single Speed Motors... The Same?

Can I rebuild This Variable-Speed Motor Myself?
It Hangs up and makes a Growling Noise at the Park Position...
Motor Sounds Fine with No Load at any speed...
Hooked to the Linkage it makes One Spin and then goes...
Grrrrrroooooooowwwwwl and stops turning.
I can force it to work with my hand helping the linkage.
I found an almost similar crappy used part on Fee-Bay for $80 bucks (Says Single Speed)
It Has a 186 Stamp under the Part Number.
I saw another w/ an 074 Stamp. What Gives?
Mine has a 195 Stamp.
I may have a Stripped Gear in mine. Will they interchange?
Will it Self-Destruct if I open it up?

front.jpg

back.jpg

num.jpg

186.jpg