well well this puts a whole new light on the subject
so there has been some backyard engineers working on this prior to your honor of working on this?
I feel for ya man *sighs*
On the Tier version i was going by what the site said about this model number truck, i guess its outdated just a tad. But yeah it is more than likely a Tier II then.
On the code listing this does not suprise me much, sometimes they have a bad habit of putting information in one part of the manual and leaving it out of another where it should actually be. I suppose if i had read through the whole thing instead of trying to find the exact information in a particular place in it i would have seen this. Skimming i guess is no good in this case :o)

All i can say is good luck finding this because it sounds like you'll need it. I'm sure you will find it though.

Edwardt,
yeah i went back and reread that and yep :o)