possible the transmission could be acting up? as if it's having some trouble shifting into overdrive?

quick story about my car - it's certified used, but the dealership i got it from didnt tell me it was in a front and rear end collision. i found weld points and some rust in the wheel well as well as bonding material in on the whole back trunk area. So, i wanted to see if maybe this is maybe related to the accident it was in. (whatever kind it was)