automatic transmission vs manual transmission harness

[dynamite196]

I have a pretty straightforward question. Truck is a 97 explorer sport 4.0 ohv with control trac and manual tranny. I decided to replace the engine in it so I got one with 50k on it and want to drop it in. Only problem is that engine was from an automatic transmission vehicle (no surprise there, seriously how many stick explorers are there?? lol) and the wiring harness is slightly different. There is an extra plug for the transmission (the automatic has two I only have one on my tranny). So here is the question, can I just leave the harness on the engine and use only one of the plugs or should I take off the harness and replace it with the original one for the manual transmission. I'm leaning towards the first as it would be a lot easier and actually seems like it should work however if anyone actually knows the answer or has done this in the past I'd greatly appreciate the info.

 

[section525]

If your current harness doesn't have the same connectors as your new harness.. I would swap them out. I would probably swap them out no matter what so you don't have any suprises after the motor is in and you find there was a slight difference betweent the two.

I had to do this when I swapped a newer motor into my Explorer and it was really not all that time consuming. Good luck!

 

[KPT]

Are you still using your stock computer?

The only connection the manual has is for the reverse lights. I'd think it would be fine to leave the extra wires hanging....

 

[dynamite196]

Ya everything is stock except the harness on the new engine. I'm thinking that the extra wires are only for the automatic and that if anything both the automatic transmission and the manual one share the same plug and the second plug takes care of all the extra stuff an auto tranny requires.

 

[410Fortune]

not always true, there are shift solenoids, the reverse light switch and the neautral safety switch. Wiring positions at the computer (pin locations) can vary from computer to computer, etc.

When you replaced your engine you should have used all your stock wiring and computer, not the harness that came from the auto donor. When you do engine transplant the thinking is use the long block with the wiring, intakes, accessories, and sensors from the truck. This minimizes the amount of custom wiring that will need to be done.
Also the auto computer should not be used to run the manual trans & engine.



OR

map out the wiring for both transmissions and figure out what needs to be changed, it is true you can leave the extra wires hanging, but dont think each plug serves one purpose, the harness is designed (tailored) to fit the truck, sensor locations. If you want to modify the trans harness to work you will need to map both the 5 speed trans and the auto trans wiring from the PCM.

Like I said the auto computer and 5 speed computer do not always have the same wiring pin locations (especially when you are talking year differences)
PLugging the auto harness into the 5 speed computer MAY also require mods at the computer plug. To find them you have to map out the harness and compare to the computer or 5 speed harness.

 

[KPT]

not always true, there are shift solenoids, the reverse light switch and the neautral safety switch. Wiring positions at the computer (pin locations) can vary from computer to computer, etc.

We are talking about a manual. Manuals do not have shift solenoids, and the clutch interlock is on the master cylinder rod in the cab. On my 4x4 manual there are only two wires, both are for the reverse lights.

 

[dynamite196]

There's a whole harness coming out of the manual tranny (probably connects to the transfer case too, i would have to double check though) not just two wires. Both engines are the same year which is the only reason I'm asking if this would work, if they weren't then I wouldn't even bother looking into it. I'm going to try and put in the engine tomorrow, not sure if I'll be ready to start it but in the worst case scenario I'll have an extra hour of work to swap out the harness. BTW, anyone know how much they go for or where I could get one. It'd be a lot easier to just take one old one off then taking two old ones off if the price is reasonable.

 

[410Fortune]

I understand we are talking about a 5 speed, but the harness you have on your engine for the PCM is for an auto and th etrans harness you asked about using is for an auto.
I personally would not even bother using the auto stuff, put the engine in using your 5 speed computer, computer harness, engine harness and trans harness.

I am fully aware of where the clutch position switch is.

both wires are NOT for the reverse lights, one is for the neautral safety switch also.
The T case will also have a couple of wires for the computer.

Save yourself the wiring changes and headaches but not using the automatic stuff when you install the engine.

I have done several auto to manual swaps and vise versa, I see no reason to keep the wiring that cmae with yout new engine, because it sounds to me like you are trying to use the entire harness that came with it, my question is why? You already have the wiring you need 100% in the truck, all you need is the engine itself

 

[dynamite196]

The auto harness is already installed on the new engine (because that's what it came with) using that harness would save me the hour of swapping it to the manual harness. That's the only reason why.