Anyone snap ears off gearbox pinion yet?

[wailinonya]

I broke the ears off the rear gearbox bevel pinion where it keys to the prop shafts slipper unit. At approx $20 a piece in American dollars for a single replacement I decided to modify the original part and reuse it. It sheared off both ears where the steel is thinest, where the little o-ring holds the bearing on. I did some serious dremeling and just reslotted the gear to key back into the shaft. Of course the length of the shaft had to be radjusted by lengthening it to pick up the excess slack it now had. So I used a small lighter torch to heat the epoxy up at the end with the one-way until the epoxy broke down and melted so I could pull the steel sleeve off and re-epoxy it and extend the length so the ends would key back together again with only slight play. It has held up great so far and now the gear has more material there to keep it from speading again. Plus the keyway actually rides inside the bearing now which should help eliminate the keyway from spreading. I think this is why they are supposed to be coming out with some kind of saver ring to keep this from happening to the diff pinions! Saved me money just took time and effort.

[YoKoMo-MX4]

Good mod, hope I don't have to do it

[Northy]

I'm fitting another bearing instead of the saver ring.

G

[Cooper]

looks similiar to me, good idea in lenghtening the shaft, could work in the Tamiya gear mod too !!!

[dmmodel]

Hi

Northy, have you found a 6x12x3 bearing with seal?

I found it only without seal

or you put another 6x12x4 bearing and you have trimmed the probe shaft end

thanks

[pro4nut]

I have ben running the bearing mod for a while, i use the 6x12x4 bearing and just took the o ring off the pinion. I felt that the o ring size gave little benefit in terms of shock absorbtion. it has also stopped me stripping spurs.

Recommended

[dmmodel]

ok.
but if you take the o ring off the pinion is free to move, if these condition is not a problem, ok, if you've already tried it without problems I'll make it too

[Northy]

Hi, yeah thats what I did, took the Oring off.

I've since found a 3.5mm thick bearing (on Ebay) that might work a little better and has seals.

G

[pro4nut]

The o ring is there to cushion any impact of the shaft against the pinion. If you leave it on there is not enough end float so you could end up transfering one failure for another.
Or get one of the bearings Northy has found.
I have run the car like this since December, i just thought everyone else had already done it.

[Northy]

pro4nut said:

The o ring is there to cushion any impact of the shaft against the pinion.

Are you sure? I thought it was an attempt to stop the pinion moving forward into the crownwheel, which it doesn't do very well BTW

[pro4nut]

The smear of black plastic on the pinion tells its own story.
Good point on what its meant to do, a circlip, or e ring would have been better for that don't you think?

[Northy]

If you look at the description on TTechs online shop it says its supposed to come with a circlip

I no longer have an Oring at either end.

G