thanks for your responses. I just wanted to make sure that I wasn't running into another transmission issue. The transmission in my other car (Acura TL, 2nd gen) went out while i was driving back in November, which is why I decided to look for a car with a more reliable transmission (tranny issues aren't fun...). The transmission in that car just went out without warning. no error codes, slipping, or flashing lights, but i did noticed that rpms were higher while driving before the transmission went out, which is why i started looking for a way to calculate the correct rpms for a given speed, so I could determine if a vehicle had a weak transmission. I feel a bit more relieved now about the issue after reading some of these posts & will update again after i get the vehicle inspected by the dealer on saturday (also planning to change fluids with synthetic ones when i get the chance).
My '98 has the same rpm's as yours on the road. I questioned it at first as well because it is running higher rpm's than other V8 cars (like Cadillacs) with 4 speeds. I've counted the 5 gears from a standstill and it is in 5th at those revolutions. Still get 26 - 27 mpg on the highway. 4.0 with DOHC is a small V8 with a lot of spool.
Just got the car back from the dealer, they stated that the transmission was ok & that it didnt need a fluid change at the moment. I found out that I do have some maintenance to do on the car (valve cover gasket, differential fluid change, left tierod end & front tires). I took it up there on saturday, but they were unable to finish, so they gave me a loaner car until they got a chance to finish. I was surprised they gave me one considering that this car is 16 years old now. Now im starting to see why people buy these cars, that treatment is pretty nice. I plan to buy the parts online & find a good mechanic to get the work done, but i guess this puts my transmission worries to rest for now. Thanks all for your advice & time!