New Bronco

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Deleted member 9101

Guest
A F-150 on 33's, you better get the deep 3.73's if you plan on towing.

I have had 3.15s and 3.55s in my F150 and had zero problems towing with 33s...lol. This isn't the 1980s... Diff ratios aren't nearly as important. ;-)

Also, the 2.7 has lots of "low end grunt."
 
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85_Ranger4x4

Well-known member
??? check that. Badlands I built (non Sasquatch), 33" tires, lockers both axles, came stock with 4.46 axles.
LOL.

I didn't catch it defaults to manual. Automatic is 4.46.

I have had 3.15s and 3.55s in my F150 and had zero problems towing with 33s...lol. This isn't the 1980s... Diff ratios aren't nearly as important. ;-)

Also, the 2.7 has lots of "low end grunt."
Kinda what I thought. It's weird they are fixated on deep gearing all the sudden.
 
D

Deleted member 9101

Guest
Kinda what I thought. It's weird they are fixated on deep gearing all the sudden.

My guess is it's "geared" towards the off road crowd. Might be to keep the tranny happy? Lower gears means less torque converter slipping, which means less heat.

Low gears + 10 speed + 2.7 Ecoboost = lots of low end power to play with. The 2.7 can move a 5500lb truck, towing a 7.5k travel trailer with out any fuss... something as small as a Bronco will be all kinds of fun in the mud with that much gumption.
 

deserteagle56

Adventurer
My guess is it's "geared" towards the off road crowd. Might be to keep the tranny happy? Lower gears means less torque converter slipping, which means less heat.
Big tires and the stock gearing most manufacturers put in their rigs these days just don't play well together. So they put in multiple overdrive gears in the tranny...and the highest ratio never gets used. This is what happened to me. With the stock 3.73 gears my rig would only stay in overdrive on a level road with no headwind - or downhill. Any kind of grade or a good strong headwind and the tranny would shift down and the engine rpms would shoot up. I regeared to 4.56 and it made a world of difference. Now it stays in overdrive most of the time. Fuel mileage? It was 12 mpg with the 3.73 gears and now, after 50,000+ miles on the 4.56 gears, I'm still at 12 mpg. But the engine and transmission are much happier.

This of course is with a gasser engine. If you are talking a diesel with all its torque coming on at 1600 rpm, the 3.73 gears would have been fine.
 

85_Ranger4x4

Well-known member
Big tires and the stock gearing most manufacturers put in their rigs these days just don't play well together. So they put in multiple overdrive gears in the tranny...and the highest ratio never gets used. This is what happened to me. With the stock 3.73 gears my rig would only stay in overdrive on a level road with no headwind - or downhill. Any kind of grade or a good strong headwind and the tranny would shift down and the engine rpms would shoot up. I regeared to 4.56 and it made a world of difference. Now it stays in overdrive most of the time. Fuel mileage? It was 12 mpg with the 3.73 gears and now, after 50,000+ miles on the 4.56 gears, I'm still at 12 mpg. But the engine and transmission are much happier.

This of course is with a gasser engine. If you are talking a diesel with all its torque coming on at 1600 rpm, the 3.73 gears would have been fine.
Not really, the overdrive in my F-150's 4R70W (4spd) is .67, the 10R60 (10spd) in the new Bronco .63.
 

deserteagle56

Adventurer
Not really, the overdrive in my F-150's 4R70W (4spd) is .67, the 10R60 (10spd) in the new Bronco .63.
So what axle ratio was in your F150? 3.31:1? What size were the OEM tires?

This is what I'm talking about. 3.31 gears are fine with an OD ratio of .67 when running 29" tires. Put some heavy 33" or 35" LT tires on the truck and all of a sudden you want that 4.46 axle ratio just so you can turn those tires and still use overdrive. That's why Jeep is now including 4.56 gears with their extreme off-road package that comes with 35" tires.

I have an F150 with the 3.5 Ecoboost and 3.55 gears. When I went from the OEM to LT tires on it there was a noticeable decrease in the truck's "get up and go" that lower axle gears would have fixed.
 
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85_Ranger4x4

Well-known member
Factory was 3.31 with dinky 235/75-16's.

I regeared it to 3.73 and it runs 32's beautifully which is close to a factory optional combination.
 

85_Ranger4x4

Well-known member
For all you Bronco fans, There will be a 3.5l/10spd on 37's with 3.5 Fox Shocks. It uses the Gen 3 Raptor power-train. It looks **************! This might be the coolest off-road production vehicle I have ever seen.
I have heard the 3.0eb rumored for the warthog/Raptor, never the 3.5.
 
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Deleted member 9101

Guest
I have an F150 with the 3.5 Ecoboost and 3.55 gears. When I went from the OEM to LT tires on it there was a noticeable decrease in the truck's "get up and go" that lower axle gears would have fixed.
Tune it... you'll have more power than stock and the tire weight will be almost irrelevant. ;-)
 
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