It's not a 2.6, but I'm sure it will be a pain-in- <img src="/forums/images/graemlins/butwiggle.gif" alt="" />
no matter what. <img src="/forums/images/graemlins/lol.gif" alt="" />
It's a '91 3.0 Automatic

Here is a summary of what's been done so far:

Checked and tightened all connections as suggested. (Only one side had the 12mm bolt, the other must have been replaced with a substitute years ago)

Battery checked with tester; saw voltage dropping below 11.5v
Charged battery for 30 min.
Same voltage drop out after trying to start.
Battery charger set to start, 55amp
Click when attempting to start.
Another 10 min charge.
Starter did turn ONCE (partial turn) then quit.
15 min charge again.
With charger connected, no sound when attempting to start.
Banged on it for good measure, then forehead and gave up.<img src="/forums/images/graemlins/shiner.gif" alt="" />

Next step? (find a phonebook, look up the word MECHANIC?? <img src="/forums/images/graemlins/lol.gif" alt="" />)