275/70-18 --- 33x10.5
About 1.25" taller than stock which would actually bring my 'overall' gearing a little higher.

 

I wouldn't worry about the gearing too much. I towed my Coleman 274BH up and over the IKE Gauntlet in my 2014 EB with 3.15 gearing. Pulled 6300 pounds doing the speed limit easily.

However DO be mindful of transmission and coolant temps. Lock out the upper gears to keep the torque converter locked. I wound up overheating twice by not doing this. It WAS in high 90's and triple digits when I towed though.

 

I pull 5K lbs of travel trailer with a 2.7L Ecoboost and the 3.31 rear end without issues. I've never had to lock out gears except when I head up into the mountains and even then it is only 6th. As stated by others I'm not as fast off the line but to be honest when I'm towing a trailer I'm not racing anything anyway. I think you should be fine.

 

Sorry to hijack slightly but i am curious about gearing. i just purchased a new to me 14 3.5EB with 3.73 e-locking rear end (max tow pkg i was told). I will be towing a 3400lbs max 20ft camper on occasion but mostly just driving on the freeway with people and gear in the truck. I would like to get better mpg so i am looking at changing gears. i see lots of info on going to 3.73 but how much and what is involved in going the other way? again sorry for hijacking. if there is abetter place for this question please let me know.

thanks

 

As someone who owns a 14 Eco with 3.31 gears you do not want to change your 3.73 gears. The acceleration on my truck is terrible empty or loaded and I am willing to bet the fuel economy on your truck is better than mine because the 3.31 gears make the engine lug and work harder. I average 15 mpg. Keep your 3.73s

 

Hmm, my 14 had 3.15 gears, and got really good gas mileage. With over 3500 miles of towing a 6300# travel trailer, including up and over the IKE Gauntlet, and tons of daily driving of 62 MPH.



If you want to go down, then I would suggest 3.55 and a tune. That way you have reasonable towing and better fuel economy. The EB likes it around 1400 RPM @ 55MPH, which is where the 14 I had sat. Unless you plan to drag race, the 3.73 gears aren't well suited for the EB, they put the engine above it's performance band with the 6 speed, but they are perfect for the 5.0.

That 14 I had was a beast, it managed to tow very well with 3.15 gears. The only downside was that it lugged if left in 5th and 6th, so had to lock out the top two gears at times. The 3.55 gears though, I had in a 16 with the 6 speed and did not have a need to lock out any gears.

 

Do you know what all is involved with going to taller gears? i kinda want to find out how much $$ is involved to see if the couple mpg's are even going to pay for it.

 

Does the gear your are in (a higher or lower) contribute to the heat load or the fact that it's shifting a lot contribute more? did you overheat the engine or trans?

 

I do, have done a couple gear changes. If doing it yourself, the hardest part is finding a bearing puller for rent. If reusing the carrier, which if you have a elocker, is a must, then the main bearings don't need to be touched, but the pinion bearings will need to be either reused, or replaced, and that is where the puller comes in handy. An average on parts is about $500, and if having it done, figure about $300-$500 for labor.

The torque convertor is what creates the heat, or I should say the non locking up of the TC in higher gears. Locking out the higher gears allows for the RPM's to sync better so the TC can lock up and not lug the engine. I found that locking out 5 & 6 when going up grades, the engine and trans temps stayed cool since they are running at a higher RPM, and with the TC locked up, it isn't generating a ton of heat from the TC. When unlocked, the TC impellers heat up the fluid and since the trans is cooled by the radiator, that combined with the turbo heat caused the truck to overheat. Once I realized this, I was able to make the return trip without overheating.