If the 2.75 gears are good, just get another pumpkin and swap it out. Then you can always put the 2.75 back in (pretty easy once you have done it a few times) if you take a long trip. If you are looking for performance I would recommend a 3.55 Traction-Lok. You can get them freshly rebuilt from Currie
www.currieenterprises.com
not cheap, but problem free.
-JON