So, I’ve got a 2007 5.7 L Toyota Tundra, bought it about 5 years ago from a guy, pretty sure he was the only owner. This trucks been great, use it as a daily driver and everything.

However, I’ve began noticing that I lose speed at going up steep hills, now I just live in SW, OK so nothing too crazy but steep hills still. This only happens at above 55-60+ mph, below that I have no problem gettin up the hill. Feels like the transmission is having to try to hard to keep at least up to speed, more often then not Ive lost 10 mph by the time I reach the top.

Any ideas on where to start with gettin it fixed? Just want to get some ideas before I take it to the shop.