removing harmonic balancer?dampener - so after reading about it i have a 2003 chevy 1500HD with the 6.0 and the harmonic balancer doesnt have the bolt holes to use the ...

so after reading about it i have a 2003 chevy 1500HD with the 6.0 and the harmonic balancer doesnt have the bolt holes to use the usual harmonic balancer removal tool so i have the use the 3 prong claw to remove it. im trying to get some insight on how to keep my crank from turning while i remove and install the harmonic balancer. ive read to use the Top Dead Center tool that screws into the spark plug hole. any insight on how that tool works? please someone give me some pointers on how to keep my crank from turning....the motor is still in the truck so cant just shove a large wrench through the bottom where the oil pan is removed...

Can you get a block of wood to get down behind it at all? I forgot how much clearance there is there, but a pry bar or a block of wood might be your best bet. otherwise maybe get creative with a ratchet strap or two?

Or if you can get to the flex plate at all and use a pry bar or screwdriver to stop it from spinning. I haven't been under my truck yet but I know the older ones had a cover you could remove with a few bolts.