Where to shim a diff

[2revo1maxx]

So the rear diff blew out in my revo the other day. I knew this would happen since I put in the sirio s27. It had at least 12-13 gallons of use on it so it's time anyway. I want to shim the new diff, what's the best way to do it? At the pinion I assume?

 

[smkynutz]

Ok, first of all why shim the new diff, does it not fit correctly? Or is there an advantage to doing this? Just curious because it almost sounds like you haven't even put the new diff in place yet, and already know you wanna shim it. Plz let me in on ya secrets.

 

[2revo1maxx]

Well it is a brand new diff, but even a new one is not very precise. It would probably go another 10+ gallons with a 3.3, but this sirio 27 has got some real torque. I know shimming will bring the gear mesh closer, allowing it to wear better. What I don't know is where to shim. I think it's between the pinion and the inside pinion bearing, but I want to make sure.

 

[smkynutz]

Ahh, now I'm understanding...my guess would be behind the pinion, when i had my revo diff apart, there isnt ant way to adjust where the ring gear sits, and you also have to consider your diff cover, dosen't seem to have much space in there. So i guess if I were to shim my diff, I would do it behind the pinion gear...

 

[olds97_lss]

Not sure on a revo, but on the large ring gear and pinion is where most shimming is done. That is, if it needs it.

Here's an old savage shim thread:
https://www.rcnitrotalk.com/forum/showthread.php?t=47876&highlight=shim