Does anyone kow of any better way to install underdrive pulleys on the 3.9L without taking the fan off or disassembling the alternator from the brackets to get an impact gun on it to break the nut loose. I'm not sure if how easy the crank would be too. If anyone knows any good tips or secrets please help. I was going to shave off part of the fan shroud on the bottom to be able to slide it out, it gets cought on the fan.

 

Might want to invest in air ratchet instead of impact its more compact to get into those spots

 

I've tried using a snap-on air ratchet and it doesn't have enough torque to get it off plus pliers hold the pulley and me cranking on it. That's y I was going to try and use my matco impact to remove it

 

Breaker Bars come in handy

 

/\/\/\/\/\/\ AGREED!!!!!!

 

+ 3 foot piece of steel pipe to make life easy

 

make sure you take the belt off. for the alternator,use a large screwdriver and turn it the opposite of what you turn the socket. the crank pully should come off after you unbolt it. use threadlock on your bolts when you install them

 

The easiest way you could do this is this way. Btw you cant take the shroud out with out taking the clutch fan off.

1) take the belt off
2) losen the radiator shroud bolts (4)
3)Use a strap wrench and a large open box wrench(1-1/4), wrap the strap wrench around the water pump pulley in a way so that when you turn the fan clutch nut the strap wrench will tighten. Remember, the fan clutch nut has to turn counter clockwise to come off. This is tricky but works most of the time. With the Strap wrench tight around the water pump pulley and the wrench around the nut push the wrench counter clock wise just enuff so tension is on the strap wrench. This will allow you to free up your hand and grab the hammer and smack the wrench around the nut. A few good hits and the nut comes free. Spin off the nut and take the fan clutch and shroud out.
4)You now have access to the crankshaft pulley and harmonic damper. There are 4 bolts that hold the pully to the damper. Even after you take the bolts out the pulley still might not come free. If it doesnt do NOT hit it with a hamer, you could easily damage it. Your best bet is to use a harmonic damper puller. Depending on your truck it might be the press on style. If it is you will need a harmonic damper puller found at most automotive stores.
5) Assembaly is just the reverse, make sure to use thread lock and tighten the pulley to damper bots at the recomended tourqe.

 

I also loosened my big nut on the viscous clutch fan with a sharp whack against the wrench with a 4 lb hammer.

I would not use thread lock on the acme threads when you put the clutch back on. I use NeverSieze to make it easy to get off in the future. With the rotation of the engine the nut stays tight.

old post below:
----
The fan on a 5.9V8 Magnum is kind of funky looking. It has 5 blades, but 2 of
them are bunched together and the other 3 are spaced out normally. There is a
stiffening wire embedded in the blades. It takes less than 15 minutes to take
this fan off, but if the fan had been made in two parts that split - you would
not have to take the big nut off the fan clutch - and the fan could be removed
in 5 minutes.

Instead of buying a 36 mm wrench {1.417 inches}, I cut two strips of metal
from a tin can. These strips turned out to be 0.010 inches thick. I taped
two such home-made 'shims' to the inside faces of my 1 7/16 wrench {1.4375}
which closed the opening up to 1.4375 - 0.020 = 1.4175 This worked fine to
loosen the clutch-to-waterpump nut. Make the shims 'fish hook' shaped and you
can tape them in place from the backside, or you could make one big U-shaped shim with some tabs at the bottom of the U for taping to the wrench.