[SB406]

cwilkie-
Sounds like your converter might not be locking up. Be careful because a 700r4 doesn't route fluid to the cooler until the converter locks. Check this out for a good article on converter lockup logic:
http://diy-efi.org/gmecm/papers/tcc.txt

72Mario-
wanna see what R's you'd be turning- Put it in 3rd gear & drive around a while. 3rd is 1:1 in a 700R like 3rd in a TH400 or 350. The preferred trans is the 4L80E which is basically a TH400 with overdrive. However, in order to run it you need a computer & wiring harness or a very costly adapter harness.

I've had a 700R behind my 406 for about 60k miles & don't have any complaints. 2nd gear is the weak link so I put in a corvette servo to boost the 2nd gear apply band holding pressure. Nice firm 1-2 shift for about $25. No shift kit in mine because they usually last about 20K in the 700r4's before stuff gets hammered and it shifts like crap.
Granted, I know that a 700R isn't the strongest slosh-box around, so I keep that in mind while driving. However, the life of any tranny is a function of how you drive it. No transmission is going to like neutral drops, brake torques, and flooring it off the line at every light. I'm not saying that your driving habits puked the tranny, but if you want to kick the hell out of it, I'd put in the TH400 or 4l80e. If you want to cruise- 700R4.