Can I replace the manual transmission in my 2004 Nissan Frontier with an automatic?
Don’t bother; it can be done but will cost you far more than the car is worth!
Ditto. The only way I could see doing this would be if you did all of the work yourself (and it will be a bunch) and had a cheap donor truck to pirate parts from.
Ditto ditto… Just off the top of my head; ECU, wiring, mounts, tranny cooler, drive shaft, linkages, and possibly gear ratio would all be different.
Just to add to Docnick and Ok, there are two routes you can take to pull this off.
Get a donor truck or find one in a junkyard with the same engine option, but with the automatic. Pull the transmission, transmission mount, flywheel, torque converter, wiring harness, ECM, driveshaft, and shift mechanism. These transmissions are controlled by a transmission module and interacts with the ECM. Your manual truck has no connectors or programming to do these functions, since it is a manual.
Find a mechanical transmission with no controller. The transmission will be 10 years older or more than your truck. Chances are that finding one that will bolt right up will be tricky. You will still need a flywheel and shifter mechanism for an automatic that fits your truck. That means probable fabrication to make it all work together. I doubt you’ll find a driveshaft that will fit and bolt right up. They most likely use a different spline connector on the output shaft than 10 years ago, and the length of the transmission will be different. Probably have to get this fabricated, as well.
I’d dump this idea. If your tired of the manual, trade it in or sell it, and buy one or something else with an automatic. I can already feel the headaches trying to get all these modifications to work together correctly.
Trade it in or outright(buy/sell) for one equipped that way.