I think i solved this problem. Futaba 9451 with one plastic gear, cannot handle in this buggy. In M1B it worked ok
I was talkin to some racers at our local track and they told me that for example in Cen Matrix Futabas didnt last longer than cpl tanks.
I changed my steering servo to Sanwas servo, cant remember model now, and it seems to last!!
Hehe... never had problems like this before!