500 miles, NO Towing. The gears need to be heated and cooled repeatedly to seat and harden properly.
Rule of thumb here is:
First 200 miles, no more than 20 mins of continuous driving, followed by at least 20 mins of a cooling period. Vary your speed/rpms. No more than 45 mph.
Next 200 miles, no more than 40 mins of continuous driving, followed by at least 20 mins of a cooling period. Vary speeds. No more than 60 mph.
Next 100 miles, no more than an hour continuous, vary speeds, not to exceed 70 mph.
At 500 miles, change the fluid, as there will be small sand size filings present from break-in. Inspect the differential. There should be NO large filings present and the fluid should not appear "burnt". This change is important, not only to remove the small filings and visual inspection, but new gear sets ship with a phosphorus coating, that burns off during break-in. This coating should not be left in the gear lube for an extended period as it has shown to prematurely break down the viscosity and lubrication properties of the lubricant over time.
Contrary to what you may have heard, or what a shop may tell you, there should not be even a hint of a whine from properly installed aftermarket gears.
If all checks out well, replace the fluid and the pumpkin cover and then DRIVE IT LIKE YOU STOLE IT...
Towing, Tires, Gears, and your Transmission.
So, you just got a level kit and 35" tires and you tow regularly. What does this do to your transmission?
With EVERY change in final ratio of 1.0:1 your transmission temperature will increase or decrease by about 25 percent at given load, and remember, tire diameter has a direct effect on final ratio. Final or EFFECTIVE ratio is determined by the following formula: Old Tire Diameter / New Tire Diameter x Gear Ratio = Effective Ratio.
So, assuming you have 3.92 gears and go from stock size tires of say 245/70r17 to 35x12.5x17s. Your EFFECTIVE RATIO would change from 3.92 to 3.47, so if your transmission was running at about 190* with no load, it would now be running at about 212*, not a big deal. But if your transmission was running at about 220* while towing a decent load (about average) then with the 35" tires your transmission would be running at about 250* WHICH IS HOT! You don't even want to see these numbers if your truck has the stock 3.55 gears!!!
A tranny cooler will help some, but the bottom line is your transmission is still generating that much heat.
To tow well, even with 33" tires it would be very advisable to make a change to at least 4.10 gears and much taller then 4.56s would almost be a necessity. According to data provided by the American Camper Association, a stock Ram 1500 has a 1000# higher towing capacity with 4.56 gears as opposed to 3.92s given equal tire size and almost a 2000# higher capacity than 3.55 gears.
If you are towing regularly, a larger pan capable of holding more fluid would also be a good mod, as would a transmission temperature gauge...
So, what does getting a different gear ratio do? Won't you lose out on top speed by going with a higher gear ratio?
Are you really concerned about top speed in a TRUCK???
Most folks change gears to compensate for larger tires. Keeps the engine at pretty much stock RPM vs. Speed when going to larger ones.
JUST changing gears, and NOT using larger tires would put the engine at a higher RPM vs. Speed. Of course, your truck would accelerate better... but yes, you would lower theoretical top speed. In reality, top speed is more limited by the engine simply not having enough power to push your truck thru the air with its brick-like aerodynamics.
Hahaha a lot of people here have 4x4 pickups, I've only got 2WD so I'm going more for a race truck haha while still keeping functionality of a true pickup. So seeing as I'm keeping stock tires, what gear ratio do you recommend for me?
for now i just got stock 3.55, looking to eventually change it, not sure what to tho. ill figure that out when the time comes that I can afford to lift the truck and put 35s on it, gonna be a while tho, wife's pregnant, so I gotta save all the pennys that i can right now.
1999 Ram Sport 5.9l V8
Everything Stock, For Now