Hello Tamiya Club!
I am new member of this forum and I need your help. I've built a TA-02S Lancia 037 about 2 months ago and I have problems with the rear ball differential.
As far as the manual goes, the differential is built correctly and it does its job well, It does not slip. The problem is the right pressure plate, the grooved part that connects the diff to the right cup keeps shearing off. I've sheared 2 so far and the dealer that I got the model from suggested I convert to a gear differential on the rear also and kindly provided me with a discount to do so. I'm awaiting the package.
I use a Torque tuned motor in it, nothing extreme, and a 2s LiIon battery.
What I did do with this model is i've run it on mix grip terrain, on patchy short grass and I sometimes like to punch the throttle mid conver to get the back to kick out.
As far as engineering goes the fault here seems to be that the rear dogbones are at an angle(being the short wheelbase version) and they do not press enough on the inside cup to keep it seated in correctly the diff, it slides a bit out of the diff, it's seated halfway let's say and it keeps rounding off over and over until there is nothing left there. There is no retainer system on the cup(like the XV-01) and this action of sliding out it seems to be it's undoing. And yes, I've included initially 1 o-ring in the drive cup and the last time i've put 2: one on the wheel side, one on the diff side, it still did not matter...
I do not know if I drive it wrong, if I've built it wrong or if it's an engineering problem. I've contacted Tamiya directly and they said that this is not a known issue.
Does anybody have this issue and even if not, can you tell me if I did anything wrong with the build or driving style maybe?