Hyper 7 transmission issue

[Bullet3.5]

Hi

I'm in need of some advice please! I have a problem with my Hyper 7 which is preventing it from starting properly. Basically when i pull the pull start the car wants to move forwards, it seems to be engaging with the transmission. Also the car won't move forwards freely as it's is almost trying to bump start the engine? Both the front and rear diff seems to be fine when I lift the car and turn the wheels individually, but when lift the and turn a pair of wheels it turns the motor over. It had been fine and this happened after some light jumping.

Any help would be most appreciated.

Thanks