Help With Animation

Hello,

I have a tank that follows an array of waypoints, and I basically want it to play an animation every time it turns left or right.

So, what I'm doing right now is calculating the distance between the tank and the waypoint and if the distance is a certain number - then play 'turning' animation.

So I have this (function Update):

 var dist = Vector3.Distance(transform.position, waypoint[currentWaypoint].position);

 if(dist <= waypointRadius + 2){
         animation.wrapMode = WrapMode.Once;
         animation["tank_leftTurn"].speed = 1;
         animation.Play("tank_leftTurn");
     }

So basically - if tank is coming close to a waypoint, begin to turn (all my waypoints are on corners)

NOTE: The tank turns anyway as a transform, when I say 'turning' animation - I mean the animation of the wheels turning.

This works - except that the animation jumps .. its like its playing animation over and over again a few times.

I also want it to turn back (so 'speed = -1.0;') after it leaves the waypoint.

Any ideas why and how I could achieve this?

Thanks