Crunchy axle gears? Read here

[OSRC]

Usually when you build a new axle, they are a little rough until the ring and pinion gears "seat" and then they start turning smoothly.

CR01 trucks are no different, except sometimes they seem a little more rough than other trucks initially. I had a set of used CR01 axles I picked up that for whatever reason never broke in - in fact they got worse. I'm building a 3rd truck out of leftovers, and I could barely turn these by hand using the input shaft. 1 spot in particular was way tight.

1 hour spent shimming, sanding, filing, grinding, swapping, cursing, and venting, and no avail. I was convinced it was the gear mesh. Finally I installed the gears/shafts back in the axle without the locking pin, and.....

Smooth as butter!

After a little diagnosis (head scratching), I found putting the locking pin all the way in and cinching it down tight was putting pressure on the axle itself and causing the assembly to go slightly out of round. (assuming this is after some wear and tear has accumulated which allows the axle to shift a bit in the diff housing.)

I pulled out the pin, drowned it with red thread lock, and installed it only until it was flush with the diff casing - problem solved.

However, I never really liked that locking pin set-up anyway, I've had it work loose and wreak havoc on the axle casing no matter how much thread lock I've basted it in. After figuring out the issue I stripped it all down, cleaned it, and did a "3rd gear" mod with JB weld insurance inside the diff. No pin needed! (and rock solid/zero play to boot)

Something to keep in mind for any of the CR01 guys.

[GraciousOne]

Yep, I loaded (and I mean loaded) my diffs with a hot glue gun. Reassembled axle, put wheels on, and twisted the wheels until I felt the veins pop out on my forehead. No slop, no play. I put the locking pin back in, but only as an "insurance" measure if the hot glue ever gives out.

Good warning (and good advice), OSRC.

[new2rocks]

I just stumbled across this and remember having the same issue when I put my CR-01 together. After playing with it for a bit (though fortunately not having had the nerve or patience to start filing and grinding), I realized the locking pins were the culprit. My solution was to leave out the locking pins altogether, on the thinking that my other rigs (3 Axial-based rigs and a Gelande at the time, a TF2 since) seem to do just fine relying on the notched axle ends plus various combinations of c-clips, bearings, etc., to hold things in place without locking pins. There is a small amount of play in the L/R rotation, but no more than on any of my other rigs (a little less, actually). Do you see any problem with just leaving the pins out?

[OSRC]

No problems here, with the third gear mod and some JB weld, that diff's not going anywhere. That locking pin is in the dustbin of irrelevancy. And less play in the axles to boot.