hey guys wondering what kind of factory tranny my 02 4x4 f150 xlt 4.6 l comes with and if its a heavy duty tran will i get better mileage if i get a trannny thats not has heavy duty (( foolish ? or not ))

 

4R70W. You can verify by counting the bolts on the pan, should be 14. It's not heavy duty, the F250's used the 4R100 which replaced the C6. 4R70W is the decendent of the AOD which was used in full size cars and F Series.

If you're considering it to save money, I vote foolish because the 4R70W is already matched to that engine to balance fuel effeciency standards from the govt vs. performance. The cost of switching everything over in an OBDII vehicle is not cheap and the gains would be minimal if any in terms of savings at the pump.

If you're doing it because you want to do it, and have the luxury of time and money to pull it off, its never foolish.

 

Swap in a manual transmission for efficiency.

 

For the cost of any changes, you can buy a lot of gas.
If you need heavey duty, the 4r70 can be custom built bullet proof.
Good luck.