Installed a GD-600 gear reduction

[CSR]

I've been running 9 tooth pinions with stock motors on my TXT-1. That set-up has worked fine for most stuff but I found myself wanting a little lower gearing when crawling really technical obstacles. I have a set of LST tires that I'll be installing soon and knew I'd need more grunt to handle the larger, sticky Losi tires. So I finally got off my ass and installed the GD-600 that's been sitting on my workbench for months. I'm running it as a 2.5:1 reduction (18T pinion/45T spur, 48pitch) with a stock 32P/15T TXT pinion on the reduction units output. If my calculations are correct, that puts my overall gear ratio at 85:1.
My pictures turned out looking like crap so I will try to explain this as best I can without many visual aids. :?
The gear reduction doesn't bolt right in, a few mods have to be made. The output shaft on the GD-600 has a diameter of 3/16", most pinion gears are made for a 1/8" shaft. There are two ways to make this work, drill out the pinion or turn down the shaft. I did one of each. I bought a extra shaft/spur assembly and turned it down to 1/8". I was afraid the amount of metal I removed from the shaft would make it weak so I didn't turn down the spare shaft. I left it alone and drilled a 15T pinion to slide over the 3/16" shaft. If the turned down shaft ever fails I have the larger shaft/pinion in my field box as a spare.
Now with the shaft situation worked out, the GD-600 is still not ready to bolt to the TXT transmission. The area picture below will need to be trimmed down to fit the TXT motor plate. I carefully used a sharp hobby knife to 'wittle' off roughly 1/8" of material around the outside edge of the bearing nub thingy.

Another option is to bore out the hole of the motor plate to accept the larger output.
Now it's time to bolt everything back together.

The motor now sits almost centered in the chassis. I'm down to one motor now but I don't miss the second motor. Run times have doubled, I can crawl with much more control but still have enough punch to nail the throttle and hop the truck up obstacles if I need to. Overall I'm pleased with this modification.

[4XADICT]

Good deal, glad too hear you like it, gear reduction is a beautiful thing. 85:1 sound like a good all around gear too, if I add any reduction to crawler #2 it won`t go any lower than 100:1, I`m going to give it a shot without it first.

[JasonInAugusta]

Man...with all the work you two are doing to the shafties, I'm starting to think you guys got your feelings hurt when the clod won in Ky.

Just messin'

But seriously...CSR has done some work since we got back. Looks like the rematch may have a different outcome.

[1beatjeep]

i run the gd-600 reduction it works great. i have a 15 pinion gear. i drill out the 15 pinion and left the shaft alone. i am at about 200 to 1 with xfactor axle it work great.

[CSR]

Originally Posted by JasonInAugusta

Man...with all the work you two are doing to the shafties, I'm starting to think you guys got your feelings hurt when the clod won in Ky.

Just messin'

But seriously...CSR has done some work since we got back. Looks like the rematch may have a different outcome.

Yeah, you and that damn Clod! I thought my TXT had the right stuff 'til I crawled with you guys. The quirks of a shafted truck are gonna be hard to overcome, but I think I'll have a better chance next time we meet up.... unless you have a few clod tricks up your sleeve!

Originally Posted by 4XADICT

Good deal, glad too hear you like it, gear reduction is a beautiful thing. 85:1 sound like a good all around gear too, if I add any reduction to crawler #2 it won`t go any lower than 100:1, I`m going to give it a shot without it first.

With the 9T pinions, I was as low as I could go without adding some sort of underdrive box. Now with two pinion gears to work with I have lots of gearing combinations. I don't think I would like the gearing much lower. Just like with my 1:1 crawler, I like to be able to get the tires spinning. If the obstacle can't be crawled in low/low, grab another gear or shift one of the transfer cases to high range. Sometimes you need momentum.

[CSR]

Oh, something I forgot to add..... you'll notice more gear noise from the external/exposed gears of the GD-600. Not that it's a big deal or a problem, just something that I thought I should mention.

[Highmark]

School has been eating my computer time so I haven't got to see the mods you've done until now-I'm scared! 8O

It really looks great, looks like I need a new shaftie

[JasonInAugusta]

Originally Posted by CSR

Yeah, you and that damn Clod! I thought my TXT had the right stuff 'til I crawled with you guys. The quirks of a shafted truck are gonna be hard to overcome, but I think I'll have a better chance next time we meet up.... unless you have a few clod tricks up your sleeve!

I thought Overkill was going to hand every one of us our asses.

I think the ol' Clod got lucky.

[EeePee]

Thanks for the write-up.

The single stock motor is enough I presume?

[fullmodtxt]

CSR, thanx a bunch for posting your findings. I have been flirting with the idea of going to a single motor. Your little writeup has made me decide to try the GD600. I like to have some tirespeed to, so the flexibility of the GD600 will be nice. Thanx again for posting! Vince

[CSR]

Originally Posted by fullmodtxt

I have been flirting with the idea of going to a single motor. I like to have some tirespeed to, so the flexibility of the GD600 will be nice.

Originally Posted by EeePee

The single stock motor is enough I presume?

The single stock motor seems to have enough power. I was either spinning the tires or trying to keep from flipping over backwards yesterday when I was trying out the new gearing, just like when I was running two motors. The motor didn't try to stall any, even when I got one of the front tires wedged in a tight spot. I also ran a 19 turn modified on it yesterday and I can really get the tires spinning with it. ;)

Try it and see how it works for you. The GD-600 is only $13 from Tower, so you won't be out much if you don't like it.

[Nomercy]

can ya use two motors with GD-600's mounted or isnt there enough room?

[rckjeep]

nope, single motor. I doubt there's enough room. But I"m sure someone could prove me wrong. The worst part about the GD600 is turning down the pinion shaft. I tried setting it up on a lathe but the macjine shop manager here at work said it would be too much work to do it right. So I hooked up a motor and filed away. Honestly it came out like Sh!t but it works.

[GReddy]

that part on the pic you said you must be trimmed cant you just leave it there and use a longer screw? cause thats what im doing

[e-maxxermatt]

where can i get that gear reduction box and for how much money

do you have any links on tower to everything i will need to put this on my e-maxx

thanks

matt g

[onewyr]

I finally get to use Twisted's favorit line " use the search button"
hahahahahahahahahahahah

[onewyr]

here is the link http://www2.towerhobbies.com/cgi-bin...&I=LXSL79&P=ML

you have to turn the shaft down so that a standard pinion will fit on the shaft

[minitrucker]

well talk about a old topic. Anyways. I have the gd-600 in my truck and I flipped the tranny so now the the motor is in the back of the truck. I have been running the stock motor and I have a set of mag mayhems and I want to use one now. I have both a reverse motor and a forward rotation one. which one do i need to use?

Thanks, Josh

[onewyr]

correct me if I'm wrong but everyone has there weight as far forward as possible right??? I would flip the tranny and put the motor towards the front. you can run either motor all you have to do is flip your diffs so the motors turn the way you want.

[CSR]

Originally Posted by minitrucker

I have the gd-600 in my truck and I flipped the tranny so now the the motor is in the back of the truck. I have been running the stock motor and I have a set of mag mayhems and I want to use one now. I have both a reverse motor and a forward rotation one. which one do i need to use?

When you flipped the tranny around the motor needed to spin in reverse rotation, the GD600 reverses the motor also, so now you need to run the standard rotation motor. ;)

Originally Posted by e-maxxermatt

where can i get that gear reduction box and for how much money

Try reading.

Originally Posted by CSR

The GD-600 is only $13 from Tower