Tranny protection

[Vinni]

Fellow S/D owners,

I have recently put a 12" lift on my 2K XcursI. I am contemplating running a set of G rated 46" tires with 20" wheels. Understandedly, running these big tires will put quite a strain on the transmission behind the 7.3 diesel.

My question for ya'll is what steps can I take to effectively protect my tranny? Would the SONNEX kit be an investment toward my goal?

Additionally, if I were to change out the gears in my diffs, would it be required for me to change out the gearing in both ends if I am in 2wd 99.9% of the time? Would you happen to have a suggestion as to what gear ratio I should be running with the 46" tires to attempt to return the truck to a stock performance level?

TIA

 

[DavidJ]

Without doing the math I'd say around 4.56 or even 5.13's might get you close with that kind of meat. Definately do both ends, if you don't the next sound you will hear when engaging the 4x4 will be the draining of your bank account and a mandatory change of drawers. I've been told 35's are max before re-gearing. The Sonnex is a great mod, but not to be used in-leu of the gearing. Also going to synthetic a bigger cooler and filter for the trans.

 

[jpxj94]

46" tires under a 12" lift will be a tight fit. Be prepared to trim your fenders and bumpers a little. Here is mine with 12"s and 38x15.50x20

 

[Vinni]

Could someone advise me on the tranny cooler replacement (best one) and which ATF would be best to run?

I bought the truck with 82K miles and am now running a 12" lift and 39.5" tires. I decided not to run the 46" tires until i can get the fully built BTS tranny; however, for now i would like to protect the tranny as best possible to avoid premature failure.

TIA

 

[hheynow]

Could someone advise me on the tranny cooler replacement (best one) and which ATF would be best to run?

True Cool 4739
Redline ATF
Magnefine inline tranny filter

 

[Strokin_it7.3]

going from 31.5'' tires to 46'' tires, a 5.44:1 would get you perfectly back to stock. because of the huge increase in rolling mass, i think 5.38's would be allright, but the best would to get one notch steeper than that. plan on bigger brakes in the future, 20'' wheels and 46'' tires put the weight of the tires far out compared to stock and that reaks havoc on brakes.