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how many hours of bashing before I have to think about rebuilding? what exactly is a crunchy diff?

I think I have the gearing dialed in as well as the slipper clutch figured out. Had a blast with the son in an empty dirt lot.

Here's what I noticed, and I'm trying to figure out what caused it. When I was going down the driveway, when I let go of the throttle, the car rolled for a little bit on its own. After 30 minutes of running, the car now simply stops on the same driveway when I let off the throttle. I guess I'm trying to figure out what tightened up. I did a tire/wheel change. Is it possible that I torqued it on tighter than the other set, causing it to stop earlier? Should I be concerned about the diff or clutch?

Thanks!

Hi arndogg, What you are describing is not a diff problem, it sounds more like your pinion gear is pressing against the spur gear to tight. It is best practice to use to #4 aluminium washers under the M3 motor screws (as in the manual). This provides a larger surface area and this way should not allow the motor to slip forward on bumps or jumps.

As far as how much time between rebuilds? I normally rebuild after every race meeting, that normally includes a practice day prior, so about approximately 2 hours total running. The rebuild is just a clean and re-grease, (maybe sand the diff rings every other time). The balls should last allot longer.

A bad ball diff will usually manifest itself by "chirping" when cornering or in bad cases under acceleration.

Bare in mind that the transmission is under allot more torque with a truck, it is really important to set the slipper so that it is loose enough to slip enough as to not transmit that torque to the diff.

Remember the stealth transmission does not require any lubrication other than on the diff balls the gears should be clean and dry, any grease will contaminate the balls and cause the diff to fail allot more quickly.

I hope this helps.

When you have the truck on a stand do the rears spin somewhat freely? If not you have the rear wheels cranked down way to much plus what the other reply said look into that also.

much appreciated!