changing my cat 3406 damper

about 1 inch. the damper and pulley will come off as one pc. then you will have to knock the old damper off the pulley.

 

Run a paint pen across the damper, pulley and onto the block before you start. There are timing marks on it. It is not fun with limited space as it gets heavy when you are holding it for along time trying to line things up. The old one is sometimes hard to get off as corrosion on the hub will keep it from sliding off nicely. If I remember correctly torque on the bolts is 168 ft/lbs?

 

I had to remove my fan blades on my 379. Dont forget to torque the bolts when you replace your Vibratech dampner.

 

Your supposed to change those every 600 k miles but I don't know anyone including myself who has except someone with broken crank, that what bad one causes.

 

never have seen timing marks on a cat damper.

 

I was wondering about the timing marks cuz I never saw it on mine when I replace it. I did paint it though before I put it on. And when had the valve adjusted made a mark on the side so I know TDC is.

 

The earlier two piece dampener had a stamped alignment marking on them to see if the pieces were slipping on themselves. They were replaced with your viscous style dampener when the electronics and higher torque engines came along, because they couldn't offset the torsional twist of the crank effectively. There are no timing marks on a new dampener. The only thing you might want to mark, is where your pulley spacer bolts to the crank, so you put your bolts back into the same holes that are clean, if your pulley spacer separates from crank, which is highly likely. Your 98 9400 probably has a single wide serpentine main drive belt that tightens at the alternator. You'll need to loosen that belt slightly, so you can realign everything properly. Make sure your mating surfaces are all clean, bolt her down and torque, run engine a few minutes and recheck torque. If some settling changes torque, I would be finding out why. Some of the 9400's had a good shot at that area from underneath, if you don't mind creeper work.