Nitro clutch gear problem

Hi All,
My savage 4.6 X shreded the teeth on the clutch bell, (metal spur gear), I changed the bell and checked everything over, all seems ok.
However The 2 speed tranny doesnt change to second unless its lifted of the ground. Put it back on the ground, and it races of ok, just wont change up. Waiting to catch the piston comming out of the cylinder head.

I know i'm old fahioned here not wanting a bl electric but i live in England, and love the smell of nitrous for breakfast.............Its cheaper than napalm.........LoL

The new clutch bell was found at the back of my toolbox, but was an hpi stock item.

Any ideas greatfully received.


Cheers


Chris