Well I need a new Rear End for my 2001 1500 Laramie 5.9L 2x4 SLT Long Bed Club Cab. I got a build sheet by looking up the VIN and it says 3.55 ratio. I found this website but don't know which ones will work: http://www.automotix.net/usedautopar...c4ee&seq_num=3 Some cost more than others and some says different engine liters. I want the cheapest one that will work with the truck. Also, is this just an axle or does it come with the differential too? Cause I would be upset if I ordered it and the differential is not there LOL. There is one that says in the description "4X2 LOCKING" and I don't know what locking means. Would that one work if I ordered it?

 

So, you have 3.55 gears. Since you are a 4x2, now would be the time to change your gearing, if you so desired (for bigger tires, towing/hauling, etc). You have a corporate 9.25 axle. 5.2 or 5.9 engine should not matter, I'm not even sure it matters if it comes out of a 4X4 (shouldn't matter on the rear axle). Technically, any 9.25 should work, as long as the width is correct, but...
If you get one from a 1500, it should bolt right up. Otherwise, it may require moving spring perches, shock mounts, etc. At this point, you could probably even move to a Dana 60, if you wanted.

 

So, you're saying I don't need a 3.55 gear ratio and I can get any ratio and it will work and fit?

 

Yes.

3.55's will get you good (relatively) gas mileage. It will be harder on the trans and drivetrain.
4.10's will be a good compromise.
4.56's if you have bigger tires or tow a lot.