i have an o2 explorer and i am putting in a 03 engine. It is an xlt 2wd. from what i read only 4wd used the counterbalance but mine had it in it. the o3 engine does not have the counter balance. will it work?

 

To my knowledge, ALL 4.0L V-6 Overhead Cam engines came from the factory with the counter-balance shaft. If you have one without it, it has likely intentionally been removed.

Various threads have been written expressing operation done after counterbalance removal, with claims that no difference in vibration was discernible. I cannot comment on the advisability of such alteration. impish

 

Actually all SOHC from 2002 up had the balance shaft. Only the 95-01 body style 2wd did not. It wouldn't matter anyway.

 

Amazing! Then, acceptable running "feel" can be had without the balance shaft? But why only used in 2WD models? imp

 

Read all about it:
Balance Shaft myth debunked!! - Ford Explorer Ranger Enthusiasts "Serious Explorations"®

Many may also be interested in this swap using late model Mustang 4.0L motors.
Mustang SOHC engine swap coming... - Ford Explorer Ranger Enthusiasts "Serious Explorations"®