Anyone installed a 4.0 in a D2 to try to get better reliability. If so what are the pros and cons.

 

It's pretty much a direct swap. But I believe you need to reprogram the ECU or use the one from the 4.0 truck. You also lose some power because of the smaller displacement.

 

I swapped out mine. No problems at all. Didn't reprogram anything.

 

Did you miss the horsepower ?? Thx.

 

What horsepower, hahaha?

Seriously, no. My 4.6 was only running on about 5 or 6 cyls when i swapped it.

 

I've swapped 4.0 to 4.6 and back, more than once. No reprogramming. No issues as long as they are both SAI, or not, and it you go from an SAI setup to a non SAI youll need to swap the heads. If, like me, you didnt start with SAI you just have to plug the holes or swap the heads. Everything bolts right up.

The difference between my old 4.0 and a freshly rebuilt 4.6 is pretty stark, power wise.

 

Thanks for the info. I think I'll stay with a 4.6 due to the power loss. Now just need to find a good engine.

 

Slap an oil cooler on the 4.6L! Still can't believe LR got cheap and left that off 03/04 D2's!