Hi all: I have a good 2.9 and a bad 4.0 Both fi., with the 2.9 being standard and trhe 4.0 auto. Is the 2.9 the same block as a 4.0? Or, to put it another way, could I bolt out the 4.0 and bolt in the 2.9? My guess is: this is too easy?! Any suggestions? Thanks for your time, Wayne.

 

The 4.0 liter block is a stretched version of the 2.9 liter block. Maybe the ends of the crank shafts will match, so you can swap over the flywheel or flex plate. But the A4LD transmission will not work well with the 2.9 engine without reprogramming the valve body, or getting a torque converter with a higher stall speed. In an case, the performance of the smaller engine will be disappointing.

 

Hi: I thought that would be the case, but nothing ventured, nothing gained. Thanks for your time anyway. Wayne