Diff gear question....

[NickTheGreek]

On one of my cars (the one I abuse) .....when I spun one back wheel by hand, the opposite wheel would spin the same direction instead of the opposite way. At the same time, everything seemed to be working fine. (As far as how it was driving, or me holding the wheels and trying to turn the spur, etc)
Anyway, being I've developed an rc10 addiction ,(while other brothers my age are coming home to read the Wall Street Journal , I'm coming home to get online and order parts....ah yeah babe) I got a bunch of parts that came in, so I figured I'd open up the tranny.
One of the diff balls had slightly meltd into the gear. Or I should say some of the plastic from the gear looked to have melted and slightly covered the ball. The other 11 seemed to be perfectly fine. It was just that one.
What would cause that??

[GoMachV]

Slippage and lack of lube will cause the melting. Usually it takes out the entire circle tho. You just caught it early

As far as turning one wheel and what the other should do- it all depends on the diff and motor. The best way to test is to hold the spur and turn one, the other should turn opposite. Then hold the spur AND one wheel, and try to spin the other. It should not want to slip easily.

[NickTheGreek]

Thanks

Now that I put it back together(wih new rings,gear and balls) the wheels spin in opposite directions as they should when I turn one by hand.

The rings were looking pretty tore up too.

Are the carbide balls a lot more durable/longer lasting than the standard??
I'm not a racer so I'm mostly asking in the sense of durability/less maintenance.

[GoMachV]

Carbide are better but they will still dig into the rings, and the rings can still slip. My recommendation is a dab of super glue on the diff ring to the hub, and make sure you use the proper diff grease and just a bit of it. Too much may help it slip too little can melt the gear. I like to put a toothpick with a glob of grease into the ball hole before putting the ball in. Wipe the excess. That has always suited me

[NickTheGreek]

I was probably putting on a lil too much.
I'd squeeze some in the hole, put the balls in n then give them a small glob on top.

The thrust bearings, I went pretty heavy on that too