My rear end just went out and I need to replace essentially everything. I am considering going to the junk yard and getting a stock version out of a wrecked truck and was wondering if I could (should) change ratios for better gas mileage. Currently it has the 3.55 rearend, 2wd, 5.9L and is getting 15mpg on a really good day. I don't pull anything or race.Any suggestions or recomendations?

 

Sorry to hear about your rear differential problem.

I have also had 9.25 differential problems twice.

If I had it to do over again
I would go to the junk yards and try to find a 2500 Ram
that has the Dana 60 rear differential:

http://dodgeram.org/tech/specs/axle/rear_axle.html

These are a bit harder to find than the Dana 70s on most
heavy duty Rams.

The shock absorber and spring mounts will have to be cut off and custom ones welded on for the Ram 1500.

You can also find Dana 60s underneath old International Harvester 4x4 Scouts that are 'almost' the right width.

Another option would be to purchase a 'Speedway' or QuickChange
differential, which is a Ford 9 inch that has a special set of gears that can be changed out to alter the ratio in about 20 minutes of relatively simple work.

Here's one weblink with pictures
but there are many shops that sell and install these diffs
in states near NASCAR tracks, like North Carolina, SC, TN, etc:

http://www.hotrodscustomstuff.com/PS-Winters.html

 

No Scout was ever produced with a D60. The D60 was an optional rear axle in the 1200 and 1300 (3/4 and 1 ton) pickups from '57-75 (end of production). The Scouts used D27s till the D44 was an option and then stanard from '68 or so till end of production ('80). If you need any measurements off an IH D60 let me know, I have 4 of them sitting outside my shop, 3 of them under trucks.

I bought my 2500 to haul around my fleet of IHs (12 at the moment but give or take 3-5 in any given month) and have the licence plate: IH HAULR

 

Thanks for the comments. I've started a search for the axles and will probably follow your suggestions. Other research has unveiled similar problems with the 1500's diff which I hope to avoid in the future. I've tackled numerous engine, transmision, and suspension rebuilds/modifications but somehow have always avoided the axles. This will certainly be educational and probably frustrating from what I hear.