Hi All. New to the hobby. Having fun with my son. Quick question on servos. The servo moves right and left when the transmitter is engaged. Seems to work. However when I connect the servo 'horn'/steering link, the wheels won't turn much, barely. Is it possible the servo and/or horn thread is stripped?

Its is definitely a possibility the servo horn is stripped. You can test it by holding the servo horn with your hand. If the servo turns, but the horn remains stationary in your hand, its probably stripped.

You should test the rest of the steering / servo system to find out what else may be problematic. Take off the servo horn and hold the protruding servo gear. Does it turn?

With the servo horn off, operate the linkage with your hand. Do the wheels turn?

*You don't need to hold the servo horn / gear super tight. Just enough to know that it's working or not.

Could also be the travel or endpoints on your radio, they could be dialed down too low for some reason. Settings on radios can get changed accidentally after all.

Another thing is it could be a weak servo. If it can turn the wheels while the car is held up in the air but not while it is sitting at rest you may need to get a new servo that puts out more torque.

A third thing is could be damaged servo, blowing the gears out can limit steering in one or both directions but the servo will sound ugly, not the hum you are used to but popping grinding sounds.

when installing a servo
on the controller
turn up the d/r (dual rate)
set the end points to r100%/l100%
and center the trim

then power on the reciever and servo to let it center
and install the servo horn as close as possible to where the servos center should be

then set the center and end points on the controller

with many cheaper kits, the centers will change as the battery drains
or the servos strip easier