Hi guys, new to this forum.
I recently picked up a used Thunderbolt. When I got it I noticed a very rough, grinding feeling from the driveline when I turned the wheels. I pulled it all apart to find it in the rear diff. The pinion had some uneven wear on the teeth, but the ring looked ok. Everything in the front diff was smooth and teeth looked perfect. After getting it all tore down and comparing the parts it was obvious the teeth on the pinions weren't cut the same. So, I ordered a set. I just got the new ones yesterday, but only to find they were exactly like my bad one. Of course I installed them to see how they felt, but no good.
Heres some links for pics I took (fullsize):




Supposedly there was low run time on this buggy. I'm guessing that is fairly true since the gears aren't total junk. I emailed Smartech, but they haven't replied yet. Maybe a bad run on the pinion gears?

So, to anyone that owns any of the Smartech cars, is this a common problem?
I appreciate any comments, thanks.