What it take to change rearend ratio

[Ric]

Hi everybody. I am new here in the board.

I like to change the rearend ratio of my dodge 3500 . . 97 auto from 3. 54 to 4. 10.

I'm planning in doing some towing in the future. An also, thinking in going to 19. 5 size tire. The engine will be upgraded to 245 HP and the corresponding mod. in the transmission.

Is it a big deal to do that? I have to add, this is a 4x4. How about cost?... . Is the speedometer screw up too much? Thank.

 

[catoiler]

Welcome, Not much trouble at all!! All you half to do is buy a gear set for the rear end and a set for the front end. Just joking It is a pain in the a$$ on a 4by. your front and rear diff ratios will half to be ths same,or else" bang" when you go into 4 wheel drive. and their goes broken parts. depending on how much you are planning to tow the 3. 54 should be good enough with your up grades,i have towed about 15000 pounds with mine and no problem, good luck!!











Mike

 

[Bigramguy]

If your not towing anything really huge,the 3. 54's should be OK. I have the same combo,with 285\75R16's,which are approx 33" tall,and have no problems. I had 35's on for a bit,and it was pretty lazy,but after upping the power a bit,it is fine now. If your going to up the power and do some trans mods,you will be OK. If you are towing a big trailer,long distances,up some big hills,a large majority of the time,then it may pay off with the 4. 10's.



The actual process for a 4WD compared to a 2WD is the same except you have to do the front as well,so double the cost. Any good shop should be able to tackle the job. As far as the speedo,with the bigger 19. 5's and the gear ratio change,it will be close,as the two will offset each other. I have found the factory speedo to be a fair bit off to begin with. Do the mods first,and then verify it,to see how much it is off. You can then change then speedo gears to correct it.

 

[Diesel Dan]

Welcome Ric

It ran me $1200 to do both diffs. as i run 35' tires it was important to get to 4. 10 so the rpm's were in the sweet range



FYI the off road shop said that they would not do it again for $1200 i guess they short qouted but they honored there qoute that is why i keep going back to them



Good luck



DD

 

[Scooby]

Ric,



It's more common for the folks with the 24V engines (98. 5 and newer) to use the 4. 10 Automatic combination since the 24Valve engines like to run at higher RPMs. Seems like folks with the 12Valves are ok with 3. 54s.....

 

[Extreme1]

Diesel Dan,

Did they have to change the carriers too?

 

[Ric]

Thanks to all who replied. After your answers, I think I will go one step at the time: Upgrade engine, mod. transm. and get maybe the 19. 5 size tires ( my Schwab "Wildcat" is running down very fast; it has 22000 miles and another 10000 miles and I will be looking for tires).

I have to say I only carry a Slide in camper now, (about 3000 lbs. overall) but it is 10 inches back because I added a fuel tank against the cab what it make wear out the back tires.

Ric





My truck: 97 auto 3500 4x4 diesel with K&N air filter, Horton fan , 4" muffler back ( no cat. ), mistery switch, custom front bumper, alum. 9" flat bed .