Big Rock Rear diff replacement - smooth running or tight diff case....but not both

[Wes13]

Haha i figured out the same thing yesterday when checking my granite mega diffs.
It was not spinning smooth and i was like checking al the teeth over and over i was almost getting crazy i couldn't find anything.
Then after some beers i finaly saw the spots on the cups.
All well in the end

 

[PatMarcus172]

Right. Im gonna check that too and get some fine sand paper out.

 

[DRBNGR]

Haha i figured out the same thing yesterday when checking my granite mega diffs.
It was not spinning smooth and i was like checking al the teeth over and over i was almost getting crazy i couldn't find anything.
Then after some beers i finaly saw the spots on the cups.
All well in the end

Its definitely the beers that fixed the problem

Im gona try that too! Thx guys, this was so helpfull.

 

[PatMarcus172]

Beer - the solution to RC problems !

 

[Wes13]

Beer - the solution to RC problems !

Correct
I was way to fixed on the teeth before the beers

 

[PatMarcus172]

I believe Beer may also be the solution of you're feeling jittery about Massive Sends !

 

[razorrc]

Beer - the solution to RC problems !

So true...

 

[PatMarcus172]

So, a quick conclusion to this thread. Thanks SO much for all the inputs and advice.
I hope this will help many existing and future owners of 3S Arrmas.

In the end what worked for me was simply going back to my original Diff yoke and the reason that worked was all down to minor production tolerances and finish in the ABS construction. To put it simply, if youve checked everything else, it could just be that the yoke isnt perfectly machined and when you tighten it to the degree that you "feel you ought to", it starts catching.
If that happens, loosen the screws a bit and try again. If you're having to loosen them more than you feel comfortable with, try another yoke - theyre very cheap and widely available. It will almost certainly be better.

 

[DRBNGR]

Hy guys, i tried all the hinds you gave. But nothing helped. I even changed all the parts. Yokes, Diff case, input gear, ball bearings. Added some shims too. But still grinding. I don't know what to do?!
What can be the Problem?

 

[jondilly1974]

Hy guys, i tried all the hinds you gave. But nothing helped. I even changed all the parts. Yokes, Diff case, input gear, ball bearings. Added some shims too. But still grinding. I don't know what to do?!
What can be the Problem?

Try taking all the shims out. Try only tightening the yoke a little at a time and see where you need to stop to keep it smooth. You don’t need to crank them down.

 

[PatMarcus172]

You can always do what I did first and have the yoke a bit loose but loctite the yoke case screws to give you some extra peace of mind. Plus, The yoke sits inside a whole other structure in the car to stop it moving around so it’s not going anywhere.

 

[jondilly1974]

You can always do what I did first and have the yoke a bit loose but loctite the yoke case screws to give you some extra peace of mind. Plus, The yoke sits inside a whole other structure in the car to stop it moving around so it’s not going anywhere.

Unless you have metal yokes, don’t use loctite. Never use loctite on plastic. It degrades it and doesn’t make your screws hold any better.

 

[PatMarcus172]

Unless you have metal yokes, don’t use loctite. Never use loctite on plastic. It degrades it and doesn’t make your screws hold any better.

Thank you. Never knew that. But loctiting a metal item (like a hex) into a plastic item is fine, right ?

 

[Kla912000]

Thank you. Never knew that. But loctiting a metal item (like a hex) into a plastic item is fine, right ?

Metal to metal is the only time you need thread lock.
A metal screw into a metal yoke-loctite.
Metal screw into a plastic power module case-no loctite.

 

[jondilly1974]

Thank you. Never knew that. But loctiting a metal item (like a hex) into a plastic item is fine, right ?

No loctite into any plastic

 

[PatMarcus172]

Awesome. Thanks guys. Learning every day !

Sadly, weather was no good on Father's day (today) in the UK Midlands, for proper RC fun...... so me and the kids took 3 RCs for a trot/rip round the block. Anyone else do that kind of thing just in order to "get out of the house" ?

 

[kantonburg]

Yeah, I ended up sanding down the input gear and diff cup on my Vorteks to get it smooth.

Only asking because i don't know.

Are you sanding the end or between the teeth?