Before replacing the motor, you'll want to make sure its receiving a full 12V and it's properly grounded. Those motors work hard, and if they're not getting full power because of a supply or ground power, they aren't going to work right.
The # LC386322 replacement motor assembly replaces the Kwikee assembly motor numbers 387738 and 386322. The other motor you'd looked at, part # LC138449 replaces a Klauber D-300 Slide-Out Motor.
For a replacement, the best way to specify the correct replacement... view full answer...