3.31 rearend
Thread Starter
|
New User
Joined: Feb 2018
Posts: 2
Likes: 0
3.31 rearend
Just bought a 2017 F150 crew 5.0 6-speed witha 3.31 rearend in it, towed my Polaris Ranger for the 1st time and I am not happy, driving 80 mph on the interstate it wont shift out of 4th unless going down a hill. What options do I have can it be adjusted in any way or can I upgrade to a 3.55 or 3.71?? Any ideas on cost to do that? HELP!!!
Hotshot
Joined: Oct 2015
Posts: 19,698
Likes: 12,822
From: Wyoming
My '07 Nissan Titan would pull my Polaris Ranger at 85 MPH just fine on the flats in 5th gear. But rolling hills would put it down into 4th for sure. I subsequently found out that the tires on my ATV trailer were only rated for 65 MPH. My Titan had the 3.36 rear end with a 5.6L engine and 5 speed transmission.
You could slow down and it would likely stay in a higher gear. My Ranger 900XP was like a parachute behind my truck, but I did have a glass windshield in mine.
My F-350 just laughs when pulling the ATV.
A tuner might help give the engine a bit more power and that might reduce the hunting of gear. My Titan was custom tuned with headers and it could chug away at lower RPM without bumping down a gear. But that was hard on the transmission.
I would think that the next most cost effective solution would be to regear. But if you're 4x4 then it will cost at least twice as much as 4x2.
You could slow down and it would likely stay in a higher gear. My Ranger 900XP was like a parachute behind my truck, but I did have a glass windshield in mine.
My F-350 just laughs when pulling the ATV.
A tuner might help give the engine a bit more power and that might reduce the hunting of gear. My Titan was custom tuned with headers and it could chug away at lower RPM without bumping down a gear. But that was hard on the transmission.
I would think that the next most cost effective solution would be to regear. But if you're 4x4 then it will cost at least twice as much as 4x2.
Cargo Master
Joined: Dec 2003
Posts: 2,182
Likes: 7
From: Saint Augustine, FL
If you are going to tow somewhat regularly I would switch to the 3.73. The 3.31 is a lousy gear for towing.
Your towing speed should suit your abilities, the road and traffic conditions and the capabilities of your equipment. When towing out west I frequently tow at 80. But I have more than half a million towing miles and my truck and trailer are more than capable. Most of the time I travel a couple of miles per hour faster or slower than traffic.
Your towing speed should suit your abilities, the road and traffic conditions and the capabilities of your equipment. When towing out west I frequently tow at 80. But I have more than half a million towing miles and my truck and trailer are more than capable. Most of the time I travel a couple of miles per hour faster or slower than traffic.
Cargo Master
Joined: Oct 2015
Posts: 2,745
Likes: 72
From: West Virginia
Just bought a 2017 F150 crew 5.0 6-speed witha 3.31 rearend in it, towed my Polaris Ranger for the 1st time and I am not happy, driving 80 mph on the interstate it wont shift out of 4th unless going down a hill. What options do I have can it be adjusted in any way or can I upgrade to a 3.55 or 3.71?? Any ideas on cost to do that? HELP!!!
If that solution is unsatisfactory to you, then re-gearing is your next best solution. I wouldn't waste time with the 3.55, that's not enough difference to provide any meaningful performance gain. I run 4.10 with a much more powerful engine and find it works better than anything I've had to date.
Switching to 3.73 will cost between $1000.00 and $1500.00 to have it done by a shop if I'm not mistaken.
Good luck.
Thread Starter
|
New User
Joined: Feb 2018
Posts: 2
Likes: 0
REALLY,, slow done to 60?? Not an option I am not retired yet
I traded a 2013 3.5 EB-- 6 speed and I thot it had a 3.55 in it but I am not sure, it would stay in 5th and would run in 6th on the flat ground, but the mileage wasnt good(8mpg) .. Anyway I will have to check into changing things out, I dont pull all the time but I cant handle it staying in 4th gear on flat ground. the sales guy said the 3.31 would be fine but I should have known better.. It was my bad..
I traded a 2013 3.5 EB-- 6 speed and I thot it had a 3.55 in it but I am not sure, it would stay in 5th and would run in 6th on the flat ground, but the mileage wasnt good(8mpg) .. Anyway I will have to check into changing things out, I dont pull all the time but I cant handle it staying in 4th gear on flat ground. the sales guy said the 3.31 would be fine but I should have known better.. It was my bad..
Mountain Pass
Joined: May 2017
Posts: 138
Likes: 3
I dont want to sound like a smarty pants here, but please slow it down, 80 is way to fast for towing, baby your engine to 60 and it will take care of you in the long run.
If your trailer tires are smaller they are going even faster!
I had a 7.3 F-350 Powerstroke and always pulled around 65...sometimes I would look down and see 70 and would coast it back down to 65.
Look at it this way: Sure youre in a hurry, but if youre out there hauling *** and hurt or kill someone while towing while over or at the upper end of the speed limit , you will have a very hard time convincing a jury that your weekend jaunt was worth all of that while you showed no regard for prudence whatsoever.
Slow down a little and dont let a lawyer get everything you have worked for.
If your trailer tires are smaller they are going even faster!
I had a 7.3 F-350 Powerstroke and always pulled around 65...sometimes I would look down and see 70 and would coast it back down to 65.
Look at it this way: Sure youre in a hurry, but if youre out there hauling *** and hurt or kill someone while towing while over or at the upper end of the speed limit , you will have a very hard time convincing a jury that your weekend jaunt was worth all of that while you showed no regard for prudence whatsoever.
Slow down a little and dont let a lawyer get everything you have worked for.
Trending Topics
Laughing Gas
Joined: Apr 2016
Posts: 850
Likes: 114
From: Virginia
REALLY,, slow done to 60?? Not an option I am not retired yet I traded a 2013 3.5 EB-- 6 speed and I thot it had a 3.55 in it but I am not sure, it would stay in 5th and would run in 6th on the flat ground, but the mileage wasnt good(8mpg) .. Anyway I will have to check into changing things out, I dont pull all the time but I cant handle it staying in 4th gear on flat ground. the sales guy said the 3.31 would be fine but I should have known better.. It was my bad..
I traded a 2013 3.5 EB-- 6 speed and I thot it had a 3.55 in it but I am not sure, it would stay in 5th and would run in 6th on the flat ground, but the mileage wasnt good(8mpg) .. Anyway I will have to check into changing things out, I dont pull all the time but I cant handle it staying in 4th gear on flat ground. the sales guy said the 3.31 would be fine but I should have known better.. It was my bad..I'm only 20 and don't drive 80 empty or loaded lol. That's just plain dangerous, especially on some roads where I live. Even on I-95 and I-295 near Richmond the speed limit is 70 at the most so I'll go 75 if empty. Towing any weight I'll stay around 65-70 depending on what I'm towing. Just slow down...it's safer and saves gas too.
Anyways, if you slow down and still want more power, then I'd regear to 3.73s at least. Hope this helps
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
Mountain Pass
Joined: Feb 2017
Posts: 201
Likes: 9
From: Vancouver Island
Even if you move to a higher rear-end ratio you might just be moving the gearing from your trans to your diff, and the engine will continue to rev where it needs to to make the power. It doesn't have the low-end torque of the EB.
Elder User
Joined: Mar 2017
Posts: 764
Likes: 30
I'm not ready to condemn him for towing 80mph yet; it would depend on where he's doing it, the equipment, etc. If he's out west, open interstates, then most everyone is going that fast. Further, it would depend on the tires he has; some now are actually rated at 81mph (I just got some D rated tires with 81mph rating). Conditions of bearings, size of wheels, etc. It may not be as dangerous as we'd first believe. Or it could be stupid. Don't know enough to make a call on that yet.
Here's the problem he has; the 5.0L is a great motor, but it's not known for low end torque. Having 3.31 gears is a very tall ratio. Wind load is greatly increased as you speed up. It's just not going to pull easily at that speed with those gears; no other way around that. You truck will certainly pull a load. It's just not optimized for towing.
About the only thing you can do is swap gear to 3.73 set. Different gear set will assist for sure; it's a torque multiplier. For any given tranny gear, a lower diff gear (higher numerically) will provide more thrust force, but over a narrower speed range.
Here's the problem he has; the 5.0L is a great motor, but it's not known for low end torque. Having 3.31 gears is a very tall ratio. Wind load is greatly increased as you speed up. It's just not going to pull easily at that speed with those gears; no other way around that. You truck will certainly pull a load. It's just not optimized for towing.
About the only thing you can do is swap gear to 3.73 set. Different gear set will assist for sure; it's a torque multiplier. For any given tranny gear, a lower diff gear (higher numerically) will provide more thrust force, but over a narrower speed range.
Lead Driver
Joined: Jun 2005
Posts: 8,465
Likes: 725
From: Calgary Canada
What's wrong with it being in that particular gear? Regearing to 3.73 (or whatever) isn't going to change where the engine needs to rev to make that power.
I towed a 7500lb travel trailer with my 2012 with 3.31 gears and it spent most of it's time in 5th gear at slower speeds than you are talking about, downshifting to 4th for hills. I'm sure if I had the 3.73's it would have been in sixth, and downshifted to fifth, but so what? Engine speed is what matters to me, not what gear I am in.
So you bought the "wrong" truck, but it's handling a pretty tough situation relatively well. 80 MPH towing anything is relatively extreme for a half ton with a gasoline engine. Maybe relax a little and either slow down or live with the situation you are creating yourself. This isn't an equipment issue.
I towed a 7500lb travel trailer with my 2012 with 3.31 gears and it spent most of it's time in 5th gear at slower speeds than you are talking about, downshifting to 4th for hills. I'm sure if I had the 3.73's it would have been in sixth, and downshifted to fifth, but so what? Engine speed is what matters to me, not what gear I am in.
So you bought the "wrong" truck, but it's handling a pretty tough situation relatively well. 80 MPH towing anything is relatively extreme for a half ton with a gasoline engine. Maybe relax a little and either slow down or live with the situation you are creating yourself. This isn't an equipment issue.
Laughing Gas
Joined: Jun 2011
Posts: 1,223
Likes: 89
From: TN
I went from 3.73 to 4.30 in my F250 4x4. Towing my TT~9000lbs, the trans would struggle to stay in OD. Did alot of miles with OD locked out. Since the swap, I can cruise at 70 in OD with no problem and will only downshift when climbing a long, moderate to steep hill. Swap cost $2500 but had a Ford dealer do the swap. Best mod I have done to the truck besides the 6.0 trans cooler. Just because the trans cooler wasn't as expensive!!!
Fleet Mechanic
Joined: Dec 2008
Posts: 1,911
Likes: 134
From: Burleson, Tx
Very odd because my 2015 will tow my 3800# travel trailer at 70 in high gear and I've got the 3.31 as well. Unless I'm in the Rockies in Colorado it will always find high gear.
I'm not sure why people say it's lousy. Sure it may have been 15 years ago when you had 4'gears but with the 6sp and now 10sp transmisssions the need for lower ratios isn't as critical.
I'm not sure why people say it's lousy. Sure it may have been 15 years ago when you had 4'gears but with the 6sp and now 10sp transmisssions the need for lower ratios isn't as critical.
