GD-600 Gear Reduction Retro for King Hauler

[Heavy Metal]

For your inspection...my version of the GD-600 retrofit for a stock KH.

Stock motor and transmission...



The GD-600 kit parts. Both 2.5:1 and 3.8:1 pinions shown. Will be using the 3.8:1 for this project. Prop shaft will get recycled for something I'm sure but no need for this project.



Here's how it all needs to go together.



GD-600 output shaft is 5mm and stock motor pinion that mates up to transmission is .125". Option here to turn the shaft down or drill the pinion out. THe GD-600 face plate has a shoulder on it that is too big for the transmission plate. Option here to cut the shoulder down or mill out the transmission mounting plate.



GD-600 shaft turned down to .125" and filed flat for set screw.



GD-600 shoulder cut down. Also had to file some relief on the bottom edges to clear the screw heads on the transmission case.



Assembled motor and transmission w/ GD-600 inbetween...



Motor will hang out over the steering and shifting servos with new assembly and requires .125" additional clearance so lowered the front servo mount with standoffs...



...and lowered the rear by lowering the rear crossmember for the servos.



Front lighting terminal board was mounted to top of servos with double sided tape before the retro so needs a new home now. Fashioned a "radiator" from aluminum and screwed down to front of servos using the servo cover screws. Drilled holes in the top corners of the terminal board and mounted to the "radiator" with cap screws.



Ready to run...



And one other note...everything now spins opposite direction with addition of a gear so had to reverse the motor leads and reverse beeper sensor going to the ESC. I think another option would be to flip a dip switch on your radio.

Working great so far...exactly what I was hoping for. Thanks for looking. Let me know what you think.

Joe