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View Full Version : GD-600 Gear Reduction Retro for King Hauler


Heavy Metal
01-09-2011, 10:51 PM
For your inspection...my version of the GD-600 retrofit for a stock KH.

Stock motor and transmission...

http://i306.photobucket.com/albums/nn265/jbothell/DSC03492.jpg

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.

http://i306.photobucket.com/albums/nn265/jbothell/DSC03494.jpg

Here's how it all needs to go together.

http://i306.photobucket.com/albums/nn265/jbothell/DSC03497.jpg

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.

http://i306.photobucket.com/albums/nn265/jbothell/DSC03499.jpg

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

http://i306.photobucket.com/albums/nn265/jbothell/DSC03503.jpg

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

http://i306.photobucket.com/albums/nn265/jbothell/DSC03507.jpg

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

http://i306.photobucket.com/albums/nn265/jbothell/DSC03512.jpg

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...

http://i306.photobucket.com/albums/nn265/jbothell/DSC03513.jpg

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

http://i306.photobucket.com/albums/nn265/jbothell/DSC03518.jpg

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.

http://i306.photobucket.com/albums/nn265/jbothell/DSC03538.jpg

Ready to run...

http://i306.photobucket.com/albums/nn265/jbothell/DSC03535.jpg

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

Lil Giants
01-10-2011, 07:02 PM
Great tutorial Joe, thank you for taking the time to make the contribution. :cool:

MACK Daddy
01-10-2011, 08:55 PM
Nice Job!...Sticky Material indeed :)


Alfy

doodlebug
01-11-2011, 12:56 AM
Thank's Joe, I like the large Picture's! Later, doodlebug

rcman
02-04-2011, 05:44 PM
nice conversion for that! I tried one but i had trouble holding the gear plumb with my drill press and it ended up walking on me and ended up out of center. i think i will have to try milling it down the next time .... thanks for the tutorial well done!

CAT29
09-12-2011, 06:27 AM
great job i am looking at doing something simular to my kh

tc1cat
09-12-2011, 08:47 AM
Great tutorial! Thanks for taking the time to take pics for everyone to see. Very nice $20 option for slowing the trucks down to a reasonable speed.:D

mazdaparts
09-14-2011, 09:01 PM
Great write up and pics. I have used the GD-600 on my emaxx and stampede trannys in my rock crawlers for years. I turned the shaft down (rather sloppy) on the one for the stampede tranny and found a 5mm/32 pitch pinion for the emaxx tranny. They do have 5mm/48 pitch pinions although the smallest I found was a 13t.

ricm
07-04-2013, 10:00 AM
hi there - I tried the GD-600 but found it too noisy - so I did a bit of DIY with some standard Tamiya gears and a shortened 'A-shaft' so noise is reduced. An alternative approach...

http://i1156.photobucket.com/albums/p566/ricm2/IMG_2662_zpsec96b0e1.jpg

http://i1156.photobucket.com/albums/p566/ricm2/IMG_2665_zpsa11506a8.jpg

http://i1156.photobucket.com/albums/p566/ricm2/IMG_2666_zps7fb4ac4e.jpg

I solved the reversing of the drive by turning the rear axles upsidedown!

civic83
07-04-2013, 06:25 PM
Has anyone tried the gear reduction units hpi sells? They are bolt on with no modifications necessary

ricm
07-04-2013, 07:29 PM
I've heard the HPI units work fine but are noisy and require quite a lot of space so you have to move the servos and/ or gearbox location.

GardenTrucking do a 4:1 reduction which bolts directly onto the back of the gearbox which might be a better option - all you need is another (shorter) drive shaft. I didn't take this option because I thought 4:1 would be a bit too slow, but is better for anybody with less confidence with DIY mechanics..

Espeefan
07-05-2013, 12:48 AM
Great write-up, and photos, Heavy Metal! I am sure this thread will help out a lot of the guys who are researching the gear reduction options for the Tamiya trucks, and for those other custom projects.

On a side not, anyone running a brushed motor, with adjustable timing, can reverse the rotation without reversing the wire polarity or reversing a radio channel. It's just a matter of rotating the motor end bell 180 degrees from it's factory position. Brushless motors can be reversed by switching any two of the three motor leads.