I have a 2004 Ram with the cummings diesel with a tow package but do not have a limited spin differential. I pull a bass boat and on some ramps I need more traction than just from one wheel. I have 355 gears and a 11.5 rear end. What can I do to get both wheels to pull. I already have off road tires on the truck but need both wheels to pull going up the ramp.
What are my options?

 

I think you answered your own question. You need a LSD or maybe even a locker in the rear of that truck.
My truck came with an open diff and I had an issue, especially on the slick red clay ramps on some of the smaller waters in Ga. when I had my bass boat.
When I re-geared to the 4.56s for my larger 35" tires I added an Auburn Gear LSD, problem solved...

 

ARB also makes a locking diff that is actuated with a togle swithch. It's an open diff normally but when you hit the switch you have a spool. Open for the street fully locked when you need it, not good locked on the highway though.

 

Where is the best place to get the parts I need.

 

usually you would have a off road shop or specialty shop do the install for you and they may want to provide the parts as well for waranty reasons. Diff work is not something you can do without the proper tools and training. Unless you are a mechanic or extremly able do it yourselfer it's not a do it yourself job.

 

Im assuming you have a 2wheel drive ?

 

if its a 4wd, toss it in 4wd, if you need more torque, throw it in lo range

 

It is 2WD

 

might want to look into a traction aiding device such as a limited slip or a locker

there are old school tricks of getting the open diff to trick it under load to transfer power as well, might want to research that