One of my RC buddies at work got his Micro RS4 today. He got the Mustang drift car. The front diff was borked right out of the box. Binding and clicking, something wasn't right. It had been a few years but it all came back to me and I had the diff out and apart in less than a minute with no tools. First thing I noticed was that it was missing the diff gear shim on the pulley side so the gear was just flopping around. Unfortunately, we didn't have any shims or washers at work so I put it all back together and brought it home with me. It needed more work than I could do there anyway.

Once I got it home and apart again, I found the right size shim but the diff was still binding and clicking. Closer inspection found a bit of plastic sprue left on one of the gears and it was binding against the casing. Someone on the diff assembly line was slacking that day. This is why I really don't care for RTRs but there's not much I can do about that. I cleaned that up and the diff now spins smoothly.

I got 2 2S 1300 LiPos for mine but the way the battery tapes to the tray, I can really only use one so I sold the second one to my buddy along with a Spektrum RX so he can use his DX4C. Now we've each got the same setup with better radios. There will be much racing and drifting before and after work .