[apfubar]

Andy,

A couple of suggestions...
- move the fifth wheel further forward, possibly just before the middle axle.... It will require a long neck on the trailer or dolly, but will ensure more weight is over the front axle.
- on the dolly, make sure you are transferring some weight to the truck, otherwise traction will be a problem..

Finally is the reduction box behind the main box, or between the motor and the gearbox?

Cheers,
Ap