For the past 6 months I'll be driving and my truck will be in second gear and about 2800 rpms it will feel like it shifted to third but still remains in second. It will drop to about 2600 then keep going. Anyone else have this problem pr may have an idea of what it might be? Torque converter? Clutches? It's a '10 3.7 auto tranny 137k just flushed and put a new filter on 7k ago.