Open rear diff?
 

One of the things I like doing with my Hammer is changing the front diff back and forth from locked to open, change tire sizes, terrain, etc.....This may be far fetched but does anyone know of a RC that might have a spider gear the same size as the Hammers with a square instead of pin slot for accepting the rear axle shaft??? I know, far fetched. I would like to have either a complete rear axle to swap back and forth with a open diff or two separate diff housings to switch back and forth.

It would be nice if Horizon/Vaterra offered this option!!

Thanks a bunch

Trwin Hammer, wraith, gmade, axial, losi, traxxas, crawler

Re: Open rear diff?
 

Front Diffs have been swapped in the TH rear after drilling the flats on the (hardened) axle shaft. I'm giving it serious consideration.
As for Vaterra offering it, my email response said no plans for any further accessories, despite what someone here said.
Search and you will find the threads.

Re: Open rear diff?
 

I'm surprised this hasn't been offered as an aftermarket part(s) yet, seems to be an item with a fair bit of interest.

I see two ways to do it effectively.

1. Replacement drive shafts with a round differential end, drilled for pins to fit the standard Vaterra Front Diff Rebuild Kit ( VTR232019 )

2. A differential gear replacement kit similar to the above, but with outdrive(?) gears with square cut holes to fit the TH's stock rear drive shafts.

I'm sure each method has challenges for mass production, but with all the part fabrication going on, it can't be done? Really??

That's the way I see it anyway.

Re: Open rear diff?
 

I had gathered some info on opening the rear diff. (Starts at post 8 )
http://www.rccrawler.com/forum/vater...-question.html
And biggamehunter actually did all the mods and ran it. (Starts at post 93)
http://www.rccrawler.com/forum/vater...upgrade-5.html

Re: Open rear diff?
 

Why ? looks easy enough to me, even if the axles are hardened.

Re: Open rear diff?
 

Well I didn't get to read your posts and links on how to do this but that is exactly what I tried ! Unfortunately I do not have a drill press and I just could not get a hole started in the hardened steel? So I took my dremel too and cut notches so that the axle shaft end is like a fork and the pin slides in it. It was very simple! The nice thing is I have 3 sets of extra axle shafts from a Axial AX10 rear that I converted to 4ws. They are the same so I can always find a drill press if I want to drill one out. But for now the slotted method works fine. I would gladly post photos but when I click to insert photo it says "Please enter the URL of your image:"...No idea what that means??

You can pick up complete Hammer rear axles with locker to wheel hexes, etc... for 46 on ebay new. So I can swap back and forth from open diff to locked by swapping the entire axle....Very easy

Re: Open rear diff?
 

Yea you definitely need a drill press and a few carbide bits to get through them. Also, heating them will remove the heat treat and weaken them so you have to flood em with lots of oil when drilling

Re: Open rear diff?
 

That slot method sound very easiealy doable with a dremel. I may try that. I have two sets of axles and I'm willing to give it ago. I was unable to drill it because I don't have proper equipment. Thanks for the info.

Re: Open rear diff?
 

I could see dlux doing it for people since he already mods axles shafts. Maybe you guys without a drill press and the proper bits could PM him.

Re: Open rear diff?
 

Dont let it get hot.

Re: Open rear diff?
 

I opened up the rear diff on one of my THs tonight. I put 500k oil in it. But I don't think I got enough in. Fills pretty loose. But I'm going to run it around a bit tomorrow and see how it does.

Re: Open rear diff?
 

it takes a while for it to flow down inside.

I gotta say I'm a bit skeptical of the "fork" technique -the fork ends are unsupported and gotta be much weaker than stock. I still say drill em if u can

Re: Open rear diff?
 

Yeah the ends get really thin with the fork method. But I have another set of axles. I figured I'd give it a try. I really wish veterra would just make some modified axles to purchase. It is so simple to swap in the already existing front diff into the rear. It just needs axles.

Re: Open rear diff?
 

Oh and I have a 10.5 novak ballistic motor that should be here on Monday. I will definitely testing durability. Currently running a 13.5 novak brushless motor on 3s.

Re: Open rear diff?
 

just remember the piece hat breaks off can easily trash the R&P
that = $$

Re: Open rear diff?
 

I'm not really worried about broken parts making their way into the ring gear. It would have to work its way through a bearing first. And as far as them getting into the spiders and side gears it is pretty unlikely too. Chances are they will sit in place just broken. Either way it is a chance I'm willing to take.

Re: Open rear diff?
 

You're right, I was not thinking clearly -

Re: Open rear diff?
 

My friends farther runs a small engineering firm that specializes in gears and gogs. Would a copy of the drive shafts in aluminium with the same round head and hole as the front be up for he job? or even a set of spider gears with a square holes to go straight on to originals work?

Re: Open rear diff?
 

Mink that is an excellent resource to have. Unfortunately aluminum would not hold up to the abuse these parts ase taking. The shafts are hardend steel ans the diff side gears are some kind of metal that is stronger that aluminum. But either of your suggestions would work if a stronger metal
could be used.

Re: Open rear diff?
 

Hey..Glad to open a great discussion...So just to keep you up to date, yes I tried the hole method first without a drill press. Remember the only reason I did the fork method is because I could not drill a hole through the hardened steel. I have a surplus of AX10 axles witch are the same so I have no problem cutting them up and experimenting with. I knew the fork method would not last too long but I needed to know if a open rear diff was something I would want to pursue with the Hammer. And hell YES...It is something i Will pursue. Its a blast on the right terrain and I tried 4 different sets of tires. Its a chameleon.

And yes...the fork did give out after 3 days of fun as hell running with a 17.5 turn sensored brushless and 3s lipo an a looser dirt track. But it answered the question I had about running a open rear diff and if you are up for the mod go for it but its best in my opinion to just start with another complete $45 EBAY rear axle and keep one of them as your experiment.

I would LOVE to see someone to come out with a square hole spider gear!!!!!

But I will always have a complete LOCKED rear axle assembly and a locked front diff sitting next to a pair of crawling tires to swap in for some different kind of fun the following day
Happy Hammering ;)