GD-600 for Gear Reduction for King Hauler

[Heavy Metal]

Will be putting a GD-600 3.8:1 GRU on my King Hauler. I've seen GRU's mounted 3 different ways so I'm asking for some pro's and cons on mounting options from those that have been there, done that.

1. Between motor and tranny.
Pros: solid mount, minimal added backlash, less wear on tranny with reduced input speed
Cons: requires modification to tranny mounting and maybe other mods, I think I read the GD-600 shaft has to be turned or filed down?

2. Direct mount to tranny output.
Pros: solid, minimal added backlash. minimal or no mods to mounts or chassis
Cons: ?

3. Mount to chassis halfway down the drive train between tranny output and diff with cups on in/out shafts for short drive shafts each side.
Pros: seems easiest option, less mods
Cons: most additional backlash of 3 options?

Other options?

Until I get my hands on the thing I have no idea what has to be done to mate these in/out shafts or attach cups. Posts I've read have not been specific on this so tips/suggestions welcome there as well. I'm a newbie so very few spare parts for this sort of thing in my shop (yet)

Also, has anyone run across spec tables online that show the length of the different model Tamiya (or other manuf.) drive shafts? Would my local hobby shop be able to look this up?

Thanks.

Joe

[Lil Giants]

You can make your own any length driveshaft and eleiminate the dogbone & cup slop.

http://www3.towerhobbies.com/cgi-bin...&I=LXJG59&P=ML

Check out this thread & entire trk tech forum

http://173.201.47.108/showthread.php?t=1094

[diesel950]

i have used a similar one and mountedit between the gearbox and motor.
the easiest way instead of turning the shaft down is to drill out the input
gear instead. and to mount the whole unit just use some spacers to lift
the unit up for clearance between motor and servo,s that way no need
for new drive shaft. then after that the cab floor needs to be cut out.
might sound like a lot of work but isn,t and also no need to drill and tap
new holes in the chassis.

[tc1cat]

You can also just put .125" spacer between the servos and their mounting. In other words, lower the servos by .125". No need for modifying the floor plate that way.

Lynn

[Mustang]

Here's a close up of a GD600 that's in my Masolite Block Truck. The servo's are lowered as Lynn described and I also added one washer under the front transmission mounting tabs on each side. Works great, no clearance problems.

Dennis

[Espeefan]

Not that the Tamiya 3 speeds are weak or anything, but in my humble opinion, it's better to multiply the torque after the transmission, then to do it before.

[Heavy Metal]

Thanks all for your suggestions and links and thanks Dennis for the photo. Going to let this one bake for a couple days until the GD-600 arrives but most likely going to drop servos .125" and mount between motor and tranny.

Espeefan - Good point on moving the increased torque downstream of the tranny...but its not like this thing is going to get worked like it's in the Lil Giants basement!

[Heavy Metal]

Originally Posted by Lil Giants

You can make your own any length driveshaft and eleiminate the dogbone & cup slop.

http://www3.towerhobbies.com/cgi-bin...&I=LXJG59&P=ML

Check out this thread & entire trk tech forum

http://173.201.47.108/showthread.php?t=1094

Joe: Thanks for the link on the yokes. I think you pasted wrong URL regarding "check out this thread..."...it links back to this thread. I'd like to read whatever it was that you intended to post. I'd like to learn more about using the Traxxas yokes, i.e., what guys are using for drive shaft stock, etc.

Regards,

Joe

[Espeefan]

Originally Posted by jbothell

Thanks all for your suggestions and links and thanks Dennis for the photo. Going to let this one bake for a couple days until the GD-600 arrives but most likely going to drop servos .125" and mount between motor and tranny.

Espeefan - Good point on moving the increased torque downstream of the tranny...but its not like this thing is going to get worked like it's in the Lil Giants basement!

Exactly, and if anyone knows the weakness of the Tamiya 3 speeds, it's Joe. So far he hasn't found one, so I am sure no harm can be done by putting the reduction in front of the trans!

[Lil Giants]

Hmmm, I guess I goofed, try again

http://173.201.47.108/showthread.php?t=708

It's the top thread in Truck Tech forum TC's "How To Custom Driveshaft"

My 6wds have 3:1 before trans and 2.1 after trans. No matter what trans you have, metal gears or nylon gears, I think it's important to be gentle with the stick movement for longevity of the drivetrain.

About the only part of the drivetrain I wear out regularly is driveshafts, but with Tim's innovative idea maybe I can extend the life of this weak link a little longer.

http://173.201.47.108/showthread.php?p=14454#post14454