Mark, checked the glove box no dice there that would have been to easy thanks for the info though. Pedro looked at my diff again no luck finding a tag or stamp telling me the ratio but I did do the driving test, according to this site http://www.ringpinion.com/Calc_RPM.aspx my axle ratio is 3.55. This calculator was pretty accurate, it says with 3.55's at 60Mph in 4th I should be turning 2325Rpm and I was turning 2300Rpm according to the trucks tac! Below are the results for 3.55's and 3.92's just in case anyone else is curious. However do keep in mind that I have the stock 265/70R17 tires which work out to be 31.61 inches tall, if you have up graded your numbers will be different. However this site has a calculator to find out the hight of your tires in inches.



Ratio: 3:55 Ratio: 3.92
Tire Height 31.61 Tire Height 31.61
Speed 60Mph Speed 60Mph

Auto*2325Rpm Auto*2568Rpm
Manual*2265Rpm Manual*2501Rpm
5 Speed*1812Rpm 5 Speed* 2001Rpm

* Auto = D in an AOD
* manual = 4th in a 5 speed
* 5 speed is calculated at .80 transmission ratio

 

I have the eq. hitch. This suspension in these trucks are made for comfort, not payload. I don't care if they say "900 lbs payload in the box". I put my 500lbs snowmobile or quad in there and it squats. I think the tongue weight of my trailer is around 900lbs, and GVW is 9200....I know, I know, its too heavy, but I only tow it very short distances. But with the bags on there, it handles it nice. Gotta get a 3/4 ton.

 

I see you have the Crew Cab which weighs about 450Lbs more than the Quad that may be some of the reason you cannot put the full payload into the bed of your truck. Both body styles have the same suspension, which I believe is a mistake on Dodge's part. I have a quad and haven't had any premature squatting issues when I put weight in the bed or tow. This is just an idea maybe someone else has some valuable input regarding this issue.

 

I have a 2011 Laramie 1500 with 3:55 and 20" tires. Thinking about getting a camper (signing on Friday!) where the weight is 6300 pounds on the lot. I'm a little nervous the tongue weight (recommended 800 lbs) may be too heavy when added to the weight of the truck and a couple of passengers ... may be right at or over the 6,700 pound GVWR. Nonetheless if I figure that out how do think this setup will perform with 7,500 pounds behind it?

 

I think you put one too many "0"s there, the Crew weighs about 40 to 45 pounds more then the Quad, lol! Part I hate is the payload is 100 pounds more on the Crew than the Quad. Both of them are too little a GVWR. They should both be 7000 or 7100 realistally. I think they'd be best to offer them with an airbag from the factory and have it monitered through the evic, complete with compressor. You would need to have 700 or so more pounds on the rear axle when already weighing 6700 to go over the 3900 axle weight.