XRAY - Model racing cars

So at this weekend's race I had my front diff make some awful clicking/chattering sounds when I get hard on the brakes. I assume it's the diff gears jumping teeth or something along those lines, but I just changed fluids and all 3 diffs appear to be perfect as far as gear wear. Could this just be a shimming issue? I have not torn it back down just yet, but will do that this week. Should I order new bevel gears anyway? The Truggy only has @ 3-4 gallons on the chassis...give or take and diff fluids have been changed at least every 3/4 gallon or so.

Bevel gears are like $17 per set or so....so I don't want to order them just for the heck of it. Any ideas here? A few locals just said "You're diff sounds like it's ready to go out". I've only been racing a year thus far, so although I have picked up a LOT of technical things quickly....their statements weren't exactly clear When I tear it down, I can take pics as well....just wanted to get this post up quick. I'm currently leading my club race series in points...and I'd like to stay that way

On a truggy due to extra force of breaking if the diffs are not shimmed it will slip/jump on the gears causing the clicking noise. Depends how long it was clicking will depend if its damaged.
Always shim it to remove as much of the play as you can by putting shims between the bevel gear & bearing attached to it. Each pack has a qty of 10 shims.
962080 ( 8x10x0.1 )
962081 ( 8x10x0.2 )

So the shims go on the diff itself under the bearing on the side of the bevel gear? I need to have a look at my pinion gears as well since I rarely check those. I just want to get these diffs back in non-clicking working order by the 22nd. Thanks for the info Brandon! I'll be tearing it down hopefully tomorrow night to see what's up with it.

and adjust the play by adding the shims. Usually you have to have some shims between the bearing and bevel gear. You still need to have SOME play there so don't shim it too much.

Awesome thanks Lauri! This XT8 has been pretty much bulletproof since I started running it...and it's the original spec to boot.

I tore down the truck completely last night...sure enough the front pinion gear got chewed up pretty badly. I had metal flakes all over the diff builkheads, the diff itself, and the pinion gear. It looks as though the Bevel gear may be OK, but the Pinion is trash for sure. I guess I found my problem

On another note, has anyone had any issues with the CVD pins coming loose repeatedly? I seem to have one wheel that refuses to keep it's CVD pin in no matter what I do. I had to replace a steering knuckle because the pin came loose and chewed it all up, and this was after the pin had come loose at least 3 times. I tore the truck down again, and the same pin is loose and chewed up yet another steering knuckle on me. The set screw was still tight, and had plenty of lock tite on it. This particular driveshaft was also new less than 1 gallon ago.

Any ideas short of maybe going to red loctite?

For all the drive pins i lightly touch the centre of the pin with a dremel, just enough to put a mark on it. THis now gives an area for the grub screw to lock on so it will not slide out. THe centre shafts have a new specific pin that is machined but for me a dremel has been fine.

Dremel sounds like an excellent tip. Just keeps sliding off the grub and man those steering knuckles aren't cheap! I've been holding off on Alum ones until I get the CVD pin problem solved. Thanks Bren. I'll give it a whirl tonight.

I did the same thing with the dremel. My right front also kept coming loose, and since I used the dremel it hasn't happened again.