Granite How do you replace the DIff & Idler Gear Set on a Granite Voltage?

MidCitySlim

Member
Messages
7
Reaction score
6
Arrma RC's
Voltage
First - my problem on my Granite Voltage is that I only get one side of the rear tires to spin when I hit the gas. Any pressure applied to the either of the wheels, and nothing spins.

The Diff cups are good (metal replacements actually), the spur gear is new and intact, and from what I can see without opening anything up, is that the gear that hits the spur gear is fully intact. Which makes me think the other gear you can't see is stripped.

Which is now my question - how do you replace the gears in AR310765? I have a feeling I need to split the chassis. Ugh....

This car breaks every single time I take it out to bash. Buyer's remorse...
 

sadlerbw

Well-Known Member
Messages
191
Reaction score
162
Yep, split the chassis. It actually isn’t that bad. You have to pull the body mounts and unscrew the servo and ESC, but pretty much everything else can stay attached, and the body is only held together by 5 or 6 screws.
 

MidCitySlim

Member
Messages
7
Reaction score
6
Arrma RC's
Voltage
So, it actually was pretty bad to split the chassis. Basically took 2/3 of the car apart.

So I got to the diff & idler gears. Nothing seems off with the teeth of the gears. Is there a way to tell if the idler gear is broken? I took it apart, and as well, it didn't seem like there was anything wrong with the teeth.
 

sadlerbw

Well-Known Member
Messages
191
Reaction score
162
Huh. Guess I’ve just done it enough that I’ve gotten faster!

Maybe the differential is broken? Did you open that up and take a look at the metal gears?

Also, I guess it’s a little late, but before you pulled everything apart, you could have taken the cover off the spur and pinion to see if they were slipping or not while you hold the wheels.
 

MidCitySlim

Member
Messages
7
Reaction score
6
Arrma RC's
Voltage
The spur and pinion are good. I checked that first.

I'm not sure which is the idler vs the diff gear. I opened up the one that has the metal gears in it. Everything seemed ok, but I know when I hold one side of the axle, the other spins freely --- I'm not sure if this is good or bad.
 

jondilly1974

Speed running rookie, 3D printing fool
Premium Member
Excellence Award
Build Thread Contributor
Messages
10,296
Reaction score
12,789
Location
Toledo, OH
Arrma RC's
Granite, Kraton 4s, Typhon 6s, Typhon 3s
The spur and pinion are good. I checked that first.

I'm not sure which is the idler vs the diff gear. I opened up the one that has the metal gears in it. Everything seemed ok, but I know when I hold one side of the axle, the other spins freely --- I'm not sure if this is good or bad.
Yes that’s the way a diff works. You should be able to grab the out cups on each side and twist them opposite directions with some feeling of resistance. The resistance will depend on what weight and quantity of diff fluid you have inside the diff. If it clicks or doesn’t feel smooth, that’s when you have issues. Spin them enough times in both directions to ensure you have spun it all the way through all the gears.

Also check for side to side play or slop in the out cups. They should not slide in or out of the diff assembly. If there is any play, check your inner bearing for damage. If not a bearing issue, you will need to shim the drive cups on the inside of the diff, under the gear.
 

sadlerbw

Well-Known Member
Messages
191
Reaction score
162
What he said!

That is normal for the differential (the part with the metal gears inside). Spin one wheel and the other wheel will spin in the opposite direction. If you spin both wheels the same direction, it should turn the spur gear.

you mentioned that you upgraded to metal outdrives. Is it possible the little screw that secures them loosened up? I had that happen to me once, and it acted a lot like what you mention.
 

Bnewman

New Member
Messages
3
Reaction score
2
Arrma RC's
Voltage
when you split it in half does the diff come apart
I split mine and one side stayed on and the other held most the diff with gears. I no my bearings are bad. I cant get the diff off either
 
Top