When I build my 56 Dodge pickup project onto my 2001 Dakota chassis, I'll change out the NV3500 5-speed manual trans for a 545RFE automatic trans. Anyone else change out their Dakota from a manual to an automatic trans? Aside from the trans and driveshaft, what else do I need to plan for? Harness? Controller? Connections to other systems? I already have another gauge set for the cab which has the transmission indicator in it. I also plan to use a Lokar or American Shifter shift control for the automatic so I'll maintain the floor shifter, floor console, steering column from my Dakota as is.

I would assume there would be converter lock up and OD solenoids an auto trans computer would want to see, or you might like to have that wouldn't be present in a manual trans truck computer. Might also be a park/neutral switch that may not be present (1st gen Dakota didn't have a clutch switch and would crank with the turn of the ignition switch without the clutch depressed) that would be a nice addition for the auto trans. Transmission kick down linkage or cable wouldn't be present in a manual trans truck either.

Gene, I knew you'd step up, thank you.

Your reply reminded me when the clutch slave cylinder failed on my 01 Dak, and I simply didn't have the time to do it myself. Called a local shop to do the work for me, about two miles from my house. Being too cheap to call a tow truck I figured I could drive it there. Put the truck in reverse, planned my path to back up, including making sure the street was clear, let the clutch out and turned the key to start. Truck lurched a bit back and started. So I backed out the driveway. On the street I snubbed it, shifted to 2nd gear, clutch out and turned the key. Lurches a bit and started right away and I was rolling. I ran a few stops signs and kept to back streets so I wouldn't have to stop. Got to the shop, rolled into a stall and snubbed it off. Dropped off the keys and reminded them, no clutch. They looked at me like, wait, he drove it here and it has no clutch?

Andy, kind of off topic, but I had a 65 Barracuda with a V8 4 speed. We were at a car show in Indy (around 250 miles from home) when the clutch shaft between the motor & the bell broke. I drove that car the 250 miles home without being able to disengage the clutch, The toll plazas were challenges, I pull it into neutral and coast to the pay booth, then shut the car off, put it in 1st and start the car. I discovered at certain RPMs you could upshift pretty easy, down shifting was a different story though. At that time that 65 Barracuda was 25 years old and was a low volume production to have a V8 and a 4 speed. You couldn't get parts for it anywhere. I was able to fix it at home.

The things we do to avoid paying for a tow! LOL!

Ha, sounds like something I would do. I once rode my 76 BMW R100RS down to a swap meet in Rockford all the way from Appleton WI. Pulled into the toll booth, pulled in the clutch and "snap" goes the clutch cable at the lever. Nuts! threw my change into the bin pushed the bike by foot and once moving clicked it into gear along with a quick stab at the starter button, off I go. With some careful rpm matching I could shift without the clutch, upshifts much easier than downshifts. Luckily the swap meet was less than five miles from the toll booth. Pulled into the meet and just came to a stop, snubbed the engine. Since a BMW airhead has been very similar for decades I just bought a used clutch cable, installed it in the parking lot and was good to ride home.

A lot of people don't know you can shift a manual trans without the clutch if you are good at RPM matching and shift feel, and double clutch. Get up to speed, pull the shifter to neutral as you let off the gas, then match your engine speed to the speed for the next gear and steadily push the shift lever to that gear, and quite often it'll slip right into gear. Before the doors of constant mesh trannys you'd commonly have to double clutch. When I worked in chassis engineering at Pierce Fire Truck in Appleton we did an order for Orange County CA for pumpers with non-synchro five speed manual trannys. I was the only one in engineering that could drive it. Just had to plan the shifts and double clutch.

add the double clutch trick to a truck that has an auxiliary or compound transmission, plus a two speed rear.
that lots of fun to master.

So would that be like an old Kenworth with the two or three shifters? I've never driven one, only seen youtube videos of truckers operatiring both hands on the shiters, and the two speed knob too yet.

it's REALLY fun to run through the gears with your arm hooked through the steering wheel.
i "learned" that by myself when i had a job at the local truck stop as a "pump jockey", a few years before i started my machinist career in 1973.
part of the job was to park the trucks in the lot after a guy fueled them up and serviced them. i had never driven a tractor-trailer unit before.
my boss said to me : "you can drive a stick in a car right ? well, a truck just has more sticks !"
well, alrighty then !

Back in Feb 1990 I was in northern Sweden at the Bosch winter test facility, working on ABS systems. I got to drive a MANN and a Scania Class 8 cabover. In both, I'm in the driver's seat, clutch/brake/throttle pedals on the floor, big engine cover/console to my right and I ask the Bosch guy, "where's the shifter?" Right there, sticking out of the console, no bigger than the shifter in a modern mini-van. For both, a sensor in the shifter knows when you want to shift (after 1st gear) and it declutches as you shift. Not like a 13 speed Road Danger at all.

Something you'll need to consider in regards to the computers. The older 5-45rfe until 2003 in most applications used a separate TCM (Transmission Control Module) to give the 45rfe it's 5th gear and I think in your case it's something to consider since, the 2004 Dakota up Dakotas combined the TCM and PCM into one unit and they did the same on the 2004 Ram as well. Not sure on the WJ platform Jeeps. I'm mentioning this because depending on your donor you'll need the TCM wiring potentially. The other thing you might need is if your donor is an 2003-2004 5.7L Hemi Ram is the wiring and sensor regarding the Accelerator Pedal Positioning Sensor.

Now I'm leaning towards the later 2012 66RFE automatic trans, as long as it will bolt up to the 4.7. The 66RFE has a slightly higher 1st gear ratio, 3.23 versus 3.0 for the 545RFE and 65RFE. That gets it closer to the 3.55 1st gear ratio I'm familiar with in the 5-speed manual in my donor Dakota chassis. Also, the 66RFE allows me to manually shift to 2nd for lower traction takeoff in the winter on slippery surfaces. It takes over automatic shifting above 25 mph which would be about right anyway. And the 66RFE has a 0.62 to1 6th gear overdrive. With the tires I plan to run, and the 3.55 final ratio in the 9-1/4 rear axle, I should be turning real close to 1950 rpm at 75 mph on the highway for decent fuel economy. Mostly flat and rolling roads around east central WI so I think 20+ mpg is possible. The 66RFE can certainly handle the torque of a modded 4.7HO (intake, exhaust, cold air intake, etc).

Comparing the first gear ratios between an automatic and manual trans is futile. The manual doesn't have the advantage of the torque multiplication of a torque converter, so its apples to oranges really.

Ha, good point, Hadn't even thought of that. Plus it makes sense when considering the performance of muscle cars with automatic trans. Used to be decades back that manual trans always won the performance comparison because of the inherent slip of the torque converter. But that was back in the days of three and four speed automatics. Current auto trans, five six and now even eight speeds are the performance choice.

For me, the option to manually shift in some lower gears could still be a control option I'd prefer for winter driving. I plan to use a floor mounted Lokar or American Shifter to control the auto trans.