http://www.youtube.com/watch?v=00eGnftj1k4
Hi Clinch..Above is a utube link to my 18 scale D9E and 1/7 scale d8 2U...The D9 is geared too slow and the D8 is geared a bit too fast.. The D8 is first and the D9 is shown in action towards the end..
I powered both with 90 degree drive auto electric window motors ( right hand and left hand) with the output shaft coming out of the transmission case at the location of the pinion gear on the real machine..I used #25 roller chain to power each final drive bull gear..A Dimention Engineering Super Sabre 25 RC speed control is used to direct the motors..The 12 volt lead acid battery is hidden in the diesel engine block..I will try to find photos taken along the way during the construction process..
I hope this helps..
Jerry