Joel,
You say the whine is most pronounced at 2500 rpm, but in what gear? Or is the whining the same in all gears?
This could be a good clue to the issue because the ring and pinion (final drive) set is rotating at a different speed in each gear for the same rpm, so if it whines at 2500 rpm in all gears it is less likely to be a ring and pinion issue.
I hear that the gear thrust washers are often the cause of whining and that 5th is most prone to having too much play requiring re-shimming.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.