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I have a 2015 F150 Platinum 4x4 with the 3.5 ecoboost engine and 3.31 gears. I am running 295/65R20 Nitto Ridge grapplers, catless down pipes, full race catback, and an SSI 87 octane tow tune.
I was towing my Jayco 29QBS that weights 9,000 Lbs. loaded over the Christmas Season. On my way home in tow haul mode, going up a fairly long and steep climb the truck did not down shift, before I made it down shift I ended up loosing my transmission. I have ordered a new one and will be installing on my own.
I am wanting to change the gears in the truck once I get the new tranny in. Right now with my tire setup I am a 3.01 ratio. Should I go with 4.10" that will make me a 3.73 with my tire setup, or go with 3.73's giving me a 3.39 ratio? I wish they made a 3.90 ratio.
I am looking at the Motive gears and master install kits for the front 8.8 IFS and the rear 9.75. I just cannot decide which ratio and would like the advise of those who have done this.
Not to be the weight police - but thats a lot of trailer for an F150 let alone a platinum. You already tore up a transmission by towing over the trucks ratings, instead of worrying about re-gearing why not shop for a 250 that is sized correctly to pull that trailer?
3.73s or 4.10s will make a huge difference. The 4.10s will cost you a little more fuel mileage if your willing to give that up they would make a better choice. If you go with 3.73s lock out 6th gear when towing.
9000lbs it not too much for a properly geared 3.5l. Mind you that trailer is longer than I would feel comfortable towing with a 150 and you're probably over your payload, but that won't effect the transmission.
3.73s or 4.10s will make a huge difference. The 4.10s will cost you a little more fuel mileage if your willing to give that up they would make a better choice. If you go with 3.73s lock out 6th gear when towing.
9000lbs it not too much for a properly geared 3.5l. Mind you that trailer is longer than I would feel comfortable towing with a 150 and you're probably over your payload, but that won't effect the transmission.
Shutt40, thanks for the input. I do understand the mileage difference, I was hoping to hear from someone who has done this and what they liked about the change or wish they did differently. I do use the equalizer wdh and the truck really has no problem handling the trailer. I don't blame the weight or the truck for the failure I should have been paying better attention to the cluster. I've got the 4.10's in the cart just haven't pulled the trigger yet.
I have 3.73s in mine but I also have the 10 spd transmission and stock tires. Mine pulls my 8000 lbs trailer with no problems, stays in 9th most of the time, 10th gear on flat hwy. I would think you should be happy with the 3.73s as a good trade off for towing and normal driving. Go with the 4.10s if you tow more often. The trick is to keep the torque converter locked to reduce heat. When it shifts down to lower gears and unlocks the torque converter it generates a lot of extra heat.
01-04-2019, 05:50 PM
Gear choice???
