ok so on wednesday i'll have my new rims and tires installed on my ram. i need to rebuild my rear end soon so i figured i might as well swap out the gears while i'm at it. what should i go with to best suit 285/75/16s? i'm not really sure whats in there now, maybe my dad will know bc it was his truck before, but i think it's stock (i have a 98 2500). also how much more would it cost me to go with a posi rear end?
Thanks,
Will

 

Need to find out what gears you have in there now. 3.55's were fairly standard.... that's what my 96 has in it. To stay 'close to stock', with the 285's, you should go with 4.10's. If you want a little bit of extra bottom end grunt, go with 4.56. (better for towing/hauling/off-roading.)

Posi/locker can cost anywhere from 400 and some, for a lunchbox locker, (just replaces the spider gears in your existing carrier) to a grand or more for a detroit locker, or similar. If you go with 4.56 gears, you will need to replace the carrier anyway.... If your truck is 4 wheel drive, need to do both differentials at the same time, with the same ratio.

 

look under your hood, my 98 has a sticker that has the truck info (engine disp. trans, transfer case model, rear end ratio etc.) but 285's are not that much larger then stock 265's....1.2 inches taller and 1 inch wider.....so you shouldnt need to change your gears unless you have some horribly high ratio......but being a 2500 it shouldnt be...do you know that you don't have a factory "posi" already, the sticker will also tell you if you do

 

it's definately a one legger. i talked to my dad and he told me it has 3.88's. can i go with 4.10's with the stock carriers?


***correction- i just looked under the hood and it has 3.5's.

 

Dana 60? 3.54 to 4.10 before you have to change carriers...

I got 285's and 3.9 and on the highway I found that at about 70 mph I was sitting at a steady 2000 rpm..and there is nothing wrong with my o/d,I was wishing it would kick into o/d at that point and lower the rpms, I have plenty of lower rpm snap too (after fixing my plenum)

 

yea it has the dana 60's. i think i might just re shim and replace the bearings in the rear end and see how that goes for now instead of dishing out the extra $$ for gears. thanks for all of the help everyone

 

You think 4.56's would work ok on that smaller tire? I'm considering doing 4.56(had previously decided on 4.10s...) on mine with the stock 17 tires, as I want a little more towing capability (and even just day to day driving seems weak with the 3.55s, I want it to have more 'life' so to speak)

 

4.56 gears, with 33's, will only raise engine rpm 200-300 at 65mph in O/D, however, it will give you great benefits in low end grunt, and around town driveability. That's what I had in mind for my truck.