My drivers side wiper arm wont move today .So I took off the wiper arm and the thing with the spline under it (sorry don't know what its called) moves when the wipers are on.So.the spline part is worn out .Removed wiper and its worn on the inside of the wiper arm but not as bad think i can get by with it.Does anyone know what that parts called and the part number and how I remove it?looks like you need a special tool?need some help here thanks all.

 

I think you are talking about a windshield wiper knurl. To my knowledge, knurls are not designed to be replaced on your truck.
Replacement or re-conditioning of a wiper knurl is likely a DIY project and a test of your ingenuity.
Also take a look at a wiper arm attachment. This is the full wiper set without the motor.
We could give you some suggestions if you want to upload a pic.

 

The wiper arm is softer metal than the "spline". So it normally strips out first. I've used steel wool wrapped around the "spline".

 

Pick your part junk yard. I see hundreds of these truck their

 

Is your spline and wiper arm cut for a machine key? My 07 has that and I got a replacement key at a hardware store. Can't even begin t guess how it got out of there in the first
place....