my revo did the same thing after about about a month of driving it. You need to adjust your slipper clutch. If you tighten your spur gear you should see the second gear again, it worked perfect for me. And if your temps are high you need to re-tune your engine. I sounds like it is probably very lean but a good way to tune your engine is to follow the flow chart that Rolex made for us. Just go to the nitro rc talk section and it is a sticky on top. I printed it out and tuned my revo in about 5 minutes with it. It now runs amazing at 230 degrees