I have a friend with a 99 3/4 ton and I was wondering if we could swap his 3.73 gears with my 4.10 gears out of a 2003 3/4 ton or just rear ends. I figured they would be interchangeable but I'm not sure or would just doing rear ends be easier

 

If they are both dana 70's maybe, but I doubt it. Why not go to a bigger tire size to help drop the gear?

 

Not long after I bought my truck I had a rear end shop replace the 4.10s with 3.73's. Cost me $900. Improved comfort at 65 a lot. I don't know what axle the 99 2500 came with but my 01 has an AAM 11.5". I would have gone for 3.55's but that would have required a new carrier for an additional $800. Hope that helps. The other reply suggests go with bigger tires. That may be a viable alternative but that would depend on what your goal is. Stock tire size is good if you are towing and just using your truck as a good load hauling vehicle. Bigger tires will change the stance and drag when driving at a steady speed. If you like to go 4 wheeling then bigger tires is probably a good idea.

 

Never heard of a AAM in a 2nd gen.

 

Huh? I thought 98.5 to 2002 were third gens. 1st gens have rotary pump, second gens have p pump, 3rd gens have VP44, 4th gens and on are common rail. Yes? I've been getting most of my info from Diesel Power and Diesel World magazines but the axle shop I used also said it was an AAM. Apparently I have misunderstood a lot. I just did some searching and it agrees with you. The rear axle according to Geno's garage is a Dana 80 on the 01 3500. They say it's also used on the 2500 with diesel & manual trans or V-10 (V-10? I'm sure those get real good fuel mileage.). I guess I'll have to go outside and crawl under it when it gets light out and see what I can find. Oh joy.

 

No 2nd gens were the p-pump and the VP's. 94-02. 3rd gens start in 03-07 (5.9) 07.5-09 (6.7). 4th gens are 10-present.

The 2nd gen dodges used the dana 70's and 80's.

 

That doesn't seem to make a lot of sense to me. Why would a 12 valve with a P pump be classed the same as a 24 valve with a VP44? They're very different engines.

 

Yes but they are same body style.

 

Wah! That makes to much sense... Wah! I was wrong. OMG!!! LOL. Thanks for straightening me out. I really thought it was about the engines.