a.308man

I'm concidering a rear end swap, with the fuel prices now creaping over $3.00 a gallon here in Atlanta. My $30.00 a day in fuel cost is killing my boat fund!!
My question is... on my 1996 c2500 with a 4:10 gear ratio and being the 8600# series truck can I drop to a 3:43 without over working my engine and trans. Also not hurting my MPG's? I currently get about 14mpg hwy out of my 329,000 all original truck. This includes the transmission. Believe it or not! I drive Alot on the 4 lane parking lots here about 120 to 150 miles per day.
Any suggestions and ideas will be greatly received.

wmiller1337

Yes you can. Sounds like your truck is a highway only truck, so it would a good idea. Probably won't get anymore than 2 mpg out of it though... And it will work your engine harder if you ever tow anything.

RacerX

3.43 is low. Your speedo wont be accurate for nothing. Why dont you look at a 3.77 or 3.83 something like that? And make the truck as light as you can(meaning no more trips to take the mother in law to Sams Club, hahaha).

a.308man

Here is what I am thinking. Only dropping a few ratios' will not help me any.?. There again I really have no idea about which one to drop to. My truck sweet spot is the 1900 rpm range. It gets about 15mpg at that point. The problem with that is... this is about 57 mph. People blow the horn at you driving that fast/slow.
and yes this is a Hwy only truck. I do need the heavy frame. Ever once and awhile I need to carry heavy cargo. Plus the 8 foot bed is a must.
Do any of you have any experiance with the diff's from, www.justdifferentials.com ?
Are these quality ring and pinions?

RacerX

Well, it maybe cheaper to add clearance lights and extra flashers and just travel at 57mph. You have a cap for the bed to aid in your aerodynamicability?