Diff slippage?

I just got my Epoch 1/43 Integra R blue body today. It seems a lot cooler than the defective Z-car (Zip Zap type) that I returned to Hobby People today. The Epoch is waaaay more car IMHO (also a lot more money for a tiny).

My problem is that I seem to be experiencing a lot of diff slip in my Epoch. The car goes downhill well but let it encounter a small uphill (like a slightly off level garage floor) and the car slows noticibly with much more noise that sounds like the diff slipping on a 1/10 scale car.

Is this normal? Can I tune the diff and tighten it up for a little less slip?

jmx