Two problems related to automatic transmission have been reported for the 2003 Nissan Frontier. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Nissan Frontier based on all problems reported for the 2003 Frontier.
Water got into my rear end on a 2003 Frontier crew cab due to a faulty abs seal and ruined the gears. Nissan had a recall on this but said my VIN# was not one of the vehicles recalled even though others of my year, make and model have been and mine had the exact same problem. Nissan said I was on my own and responsible for all repairs.
Nissan murano 2003 has problem with pressure sensor inside transmission. This causes the vehicle to hesitate, 10-15 seconds before you can accelerate. This only started 2 weeks ago and I have 89k miles on it. I almost was stuck by an oncoming vehicle due to the hesitation. There are many more stories like mine on edmunds. Com. Nissan does not acknowledge any problem with the transmission but clearly states that the defect was corrected in the later models. Big safety issue, please look into this ASAP before someone is killed.