I'm going to put 4.11 in the front and rear of my 97'4x4. It is an automatic with overdrive. I have 33 inch tires and I wonder how high would the RPM's be at 80 mph....and how bad is it on the tranny and on my truck to run at those speeds? And also if I put a Detroit locker in the rear would it drive on the pavement a lot different.