Just installed my Underdrive Pulley on my 2008 4.0
Pain in the assssssssssssssssssssssssssss!!! wasnt too hard pulling the fan and shroud out since we had that fan pulling tool, but getting the old pulley off was the worst because we didnt have the right bolts for the puller and wouldnt work properly. So we got it almost all the way off and used crowbars braced on the sway bar to pop it off.
Once the old pulley was off, the new one was easy to throw on.
The truck pulls harder now, you can really feel the difference under hard acceleration, just got to regear not to 4.56s for my 33's and shes going to be even faster!
All and all, pain in the *** about 3 or 4 hours work to get this new pulley in all said and done. Labour was free as i do electrical work for the shop i get my truck work done at.
Not sure if im fully satisfied with the results but they are noticable, no idea how much the gain was though. And i will update evryone on my gas status on the next tank!
DOUBLE LIFTED and PREKEYD, 17x9 Eagle Alloy 197's, 35x12.5 Hankook Dynapro's, black headlights, 3" flowmaster exhaust, UD Pulley, K&N, JBA Headers, Motive 4.56 gears, Superchips Flashpaq Performance tuned, FOX shocks, Pioneer sound and much more.