What truck is needed to tow TT weighing 10k lbs.

I believe the V-10 of those years with the 5 speed auto and 4.10 will do fine. 4.30 will pull very good. I would say almost as good as a diesel of the time. My X with the V-10 and 4.30 gears and 4 speed auto has no issue with the steepest of grades. The slowest I've done was 55mph on I77 south in VA or WV (I forget where exactly). The mountains there are just as steep as our west. I would go for the V-10!