So I just got a twin hammers! Help please

[Mikael]

So I just got a used twin hammers with some really good electronics.
Anyways when I got it and paired the controller it was working (turning, driving) at that time I didn't have the wheels on so when I put them on and I try to drive the car it makes a kind of gear grinding noise. When I press the trigger the gears spin but it's not moving the drive shaft. When I roll the drive shaft with my fingers the wheels move. Also the pinion gear is a bit rusty. Any ideas? It makes a "Whiiir" noise.
Here are some pics

Mikael_m29's Library | Photobucket

 

[old man 52]

Make sure its not stuck between gears.

 

[Mikael]

okay ill try that. Thanks

 

[Mikael]

That's not it I forgot to say but the esc is making a buzzing noise too.

 

[Crank]

Have you checked-
for binding
the slipper
the motor turning
Have you removed the spur gear cover?
have you disconnected the shift servo and tried to manually engage high and low gear.

Process of elimination "thumbsup"

 

[Mikael]

K thanks I'll try all those

 

[ndi_guy]

Did you get it figured out yet?