Is there anyway to test if your servos have gone bad in the way of being stripped? Mine servos turn the elevator but if you make a quick movement by holding the servo arm and push one way or another you can here it sound as if it is sliding over teeth. Does this suppose to happen?</p>

#1 are you sure you have the right servo arm on the servo. That could cause some slippage. If you do, then take the top off of the servo to look at the gears and if one is stripped you will be able to see it. I'm sure others will have other suggestions also.

If you can hear teeth sliding, that is never a good sign. Take off the servo arm, and CAREFULLY open the top of the servo to expose the gears. IF any teeth are broken, replace the gears if it's an expensive servo, or just replace the servo if it's a cheapie

Are these Micro servos?

It doesn't take a lot of force to strip many Micro servos.

Restraining the control surface to test these servos is NOT a good idea.

If you can make them slip then they are no good. Don't fly with them like that.

If you can make them slip then they are no good. Don't fly with them like that.

As goirish said - make sure the servo arms are correct for the sevo. JR. Hitec and Futaba (and many more) are all different, but in some instances appear to fit.
Learnt this some time ago when I had Htec arms on a JR servo. Worked on the bench - but failed in the air - big time.

My test is to hold a control surface and slowly move the stick to the two extremes. Not really restraining the control surface . . . just keeping the model on it's wheels but lifting or tipping it enough that the control surface is supporting some of the weight - maybe 30%. If it "skips" noticably or fails to return to the zero point you have a bad servo/missing gear teeth.