Should I do this?
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Should I do this?
My truck is meant to be a TT hauler, see sig below. I have been thinking about having the 3.55 ring and pinion gears, 4x4 so front and rear, replaced with 4.11. Is it worth it? I plan on keep the truck for 2-3 more years and there will be plenty of trips towing the TT.
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Did you buy the truck new and or did you do all the mods? If so, I say yes but it will be expensive.
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I bought the truck 2 years ago, but I did do all the mods. My plan is to get a F250 PSD in about 2-3 years, so maybe I should just hold out and leave the Expe be for now. I just know she'll tow that much better with the 4.11 gears!!!
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From: Littleton CO
How does it pull now? 3.0 to 4.0 gears is a 25% change in RPMs. 3.55 to 4.11 is 12-13%. Yes it will pull better but at what RPM. Are you in OD when at highway speeds? On my Diesel I am, on my Expe. I am in Drive (not OD). Is is worth the parts and labor to make the swap? You are the only good judge there. Bill Gates wouldn't think twice....
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I tow with OD off so I am in 3rd gear locked up most of the time. With the 3.55 I run right at 63 MPH at 2500 RPM which is also right in the torque sweel spot for the 5.4L 2V. If I go with the 4.11 gears I will need 2900 RPM to run the same 63 MPH in third gear. I may lose a little torque (not much), but think of the mechanical advantage I'll gain and the reduced wear and tear on the engine and tranmission. Yeah I know it's hard to say 2900 RPM is easier on the drivetrain than 2500 RPM, but in this case it is...it'll talk less fuel/combustion/energy to achieve and maintain the 4.11 gear/2900RPM than it does to achieve and maintain the 3.55 gear/2500 rpm.
What will this cost I wonder, $2k, $3K???? Any ideas?
What will this cost I wonder, $2k, $3K???? Any ideas?
Laughing Gas
Joined: Jun 2005
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Well, there are a lot of factors that you need to consider. First, yeah, these trucks are extremely under geared from the factory. With the torque peak happening at a higher RPM range in the MOD engines, Ford should have made 4.11 standard in these trucks with an option for 4.30s or 4.56. I've ran a lot of MOD engines, and have done a ton of research, and the common consensus, from my personal experience and others opinions, is just that. I plan on replacing the gears in my Expo with 4.56 (and air lockers but that's another story) as soon as I round up the funds and time. But I can do my own work and I plan on keeping the truck for foreseeable future.
You, on the other hand, plan on replacing your truck fairly soon. If you can do the job yourself it shouldn't cost that much. I think a gear set is running around $200-$250 ea for a reverse rotation 8.8 and 9.75. Bearings, oil and gaskets will run you another $100-$200. That seems fair to me considering how you're working the truck. If you have to have someone do it for you, I have seen quotes from $1.5K-$2K and some higher. I think that is a lot of money to put into a truck that you're going to replace.
You, on the other hand, plan on replacing your truck fairly soon. If you can do the job yourself it shouldn't cost that much. I think a gear set is running around $200-$250 ea for a reverse rotation 8.8 and 9.75. Bearings, oil and gaskets will run you another $100-$200. That seems fair to me considering how you're working the truck. If you have to have someone do it for you, I have seen quotes from $1.5K-$2K and some higher. I think that is a lot of money to put into a truck that you're going to replace.
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The 3v MOD engines have to rev higher to get the same torque as the 2V.
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I think running 2900 rpm is counter productive. Having it cruise on the torque peak is the most efficient place for the engine to run.
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Laughing Gas
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Okay, the 5.4 is a better engine than the competition. That's why most of us own Fords and not something else. But when we start comparing the MOD motor's torque curve to, say, a 351, 460 or 300 six and what do you find. While the pushrod motors can lug down and grunt the MOD motor has to rely on the trans to kick down and send it's revs to the moon.
This is from experience. I've pulled heavy loads with all three MOD motors as well as pushrod motors. It doesn't make sense. The 5.4 and the V10 are long stroke engines. Compared to the relative short throws of the 351 and 460 they should make a crap load of torque down low. Somehow this doesn't happen.
But this is off topic. The question was should the OP swap gears. In my experience; yes, if you can justify the cost, it would make a big difference in your towing ability.
This is from experience. I've pulled heavy loads with all three MOD motors as well as pushrod motors. It doesn't make sense. The 5.4 and the V10 are long stroke engines. Compared to the relative short throws of the 351 and 460 they should make a crap load of torque down low. Somehow this doesn't happen.
But this is off topic. The question was should the OP swap gears. In my experience; yes, if you can justify the cost, it would make a big difference in your towing ability.
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From: Littleton CO
I went from a 350 powered Suburban to pre vortec 454 and then vortec 454 suburbans to pull my travel trailer. Got 4-5 mpg with trailer (13 without) on runs from Colorado to California at 70-75 mpg. Time was worth more than the MPG on those runs. 20 hour 1200 mile overnight pulls. I finally bought a 2000 Crew cab with the 7.3. Mileage went to 12 MPG same trailer, trip and speeds! Now that I had the pick up had to switch to a 5th wheel (bigger still). Same trip and speeds I'm between 11-12 mpg. Pulling with a diesel is SO much less work. No down shifts, holds speeds on most grades. For the daily drives and other trailer work (horse and car trailers) I use the Expedition mostly. I hope to never be without a diesel for the big pulls again. I was never a GM guy, but back then the Excursion was simply out of my price range.
Laughing Gas
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No problem, I'm here to help and share my knowledge gained by personal experiences. I think you're probably making the best choice. No need to use money on something that will be replaced in a few years.
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I did spring for a transmission fluid temp gauge, had it installed two days ago by my local Ford dealer. They put the sending unit in the pan rathenr than use the available test port. Anyway, the gauge works great and I know when to pull over and let her cool off when towing in the mountains and such.
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I did spring for a transmission fluid temp gauge, had it installed two days ago by my local Ford dealer. They put the sending unit in the pan rathenr than use the available test port. Anyway, the gauge works great and I know when to pull over and let her cool off when towing in the mountains and such.
The pan is a better location IMO than the test port. I had very slow response from the test port.