A 3/8" rachet will work. If you have the 10. 5 rear axle, level will be 3/4" below fill hole +or- 1/4" . Mine was 1" below hole, so I topped it off with some Mobil 1 synthetic gear oil... ..... Its alot cheaper than the dealer synthetic. :D
2003 Ram 2500, qaud, 4x4... ... ... got it July 03