2012 Differential.

[Barbieri]

I currently own a 98. 5 2500 with the Diesel engine. I am researching the 2012, 2500 with the 6 speed auto and am stumped as to what differential I should get. I tow a 31ft Airstream at 9000lbs. I only tow about every other year. Places like Alaska, BC, Canada, California and Eastern Canada. Where I live in south Texas is just hilly and consequently the 4. 0 to me is not necessary. The question is with the 3. 73 or 3. 42 differential. I am inclined to the 3. 73 but am also considering the 3. 42. I have at times with the 98. 5 auto trans had to downshift to first. Like in Utah and Monarch Pass. I have researched back issues and didn't find any articles that answered my question. I would appreciate any and all help.

 

[Hoefler]

I would certanly not go any higher than the 3. 73 for towing that sized load. You would be down shifting at every grade no matter how slight.

 

[Bob4x4]

With the 6spd auto 5th wont lose much road speed so the 3. 73 should be good enough with the Airstream.

 

[Barbieri]

I appreciate the reply but recently I read a small article in a past edition about the 3. 4 being TOO TALL. Now what does that mean. It's Greek to me. I expect to down shift even if it's an automatic. After all the shift is marked with other options besides D. If I drive in Kansas then no problem, right. I don't ignore what people write. I evaluate and try to make a BEST educated guess. So please direct me to the place that will provide me with the information I can evaluate and make a Best educated guess. Have a nice day.

 

[mpaulson]

The 3. 73 will be fine in the mountains in my opinion. This is what I have and I have a total weight of 24,000lbs with major wind drag. Can you get the 3. 42 with the auto? In my opinion, I wouldn't want the 3. 42 ratio.

The smaller the number (3. 42), the lower the RPM at a set speed and less HP to the wheels. The bigger the number (4. 10) the higher the RPMs for the same gear at the same speed, but more power multiplication. This comes into play the most at take off from a stand still.

The link below will give you a bunch of charts to all the transmission/gear set combinations that there are for the Dodge's. You can type in your own gear ratio in the ratio box and the rest of the numbers automaticaly change to suit it.



http://www.klenger.net/dodge/general-reference/gear-speed-calculator.xls

 

[Simplysmn]

Why not just get the 410's then they pull the best Don't they ??????

 

[Barbieri]

Thank you very much. I can study what you sent me. I cannot go over 65mph. That is the speed limitation on the trailer tires. They are Goodyear Marathon. I'll bet most people didn't know that. I see Airstreams going down the road passing me. I do 60-65. So they have exceeded the speed range of the tires. So speed is not my concern.