I recently purchased a 96 Disco with a blown engine for the body panels to repair my daughters 98 Disco. I have also located another 96 that is supposed to only have a bad main ECU. Should these be interchangable since they are both '96? Is this located near the coolant reservoir?

 

Pretty sure you have to have testbook to "learn" the new ECU. It is by the washer reservoir.

 

Yes you can put it in the new truck, but like already mentioned the donor ECU will have to set up to match the new truck.
The ECU learns how the car is running and makes adjustments through the engines life to account for engine wear, drive cycles, grade of gas used, etc.
You could drive the new truck with the donor ECU but it will run like crap for 500 miles or more until it re-learns the "new" engine.

 

Anything I can do other than just connect it and drive?

 

So just remove the old one and connect the new one? Is there a way to "clear" the donor ECU?

 

As far as I know there is no DIY way to "clear" the donor ECU.

 

Just to make sure you understand, after installing the ECU, it must be towed either to the dealer or a shop that has a test book or similar scanner to be set up, this is the only way the truck can then be restarted.

 

I don't know if this can apply but I recently had to change my ECU due to rust issues. I didn't have to get my new one set up for my truck. It was plug and drive.

The truck started the first try and it solved my high idle issue. My truck is a 1998 Disco.