I have an '03 F250 4x4 SCLB. I just bought a 31' 5R. It weighs 13k loaded. Here's the deal: I have 3:73 gears.. I haven't installed the hitch yet. Do you think I'll be ok pulling the trailer up over 7k mountain passes, or will I have to upgrade to 4:56 gears? I didn't like the way it pulled my 4k BP in Colorado and am very concerned about yanking three times the weight. I'd been threatening to change to a diesel, and the PO of the trailer is willing to swap his 2000 PSD straight across with me. Mine is a Lariet with 104k on it and his is an XLT with 91k (2WD). Which makes more sense to you? Appreciate any input; thanks.

 

Do you use it the winter? would the 4 wheel drive be missed? Is yours used daily or for short trips?

Plenty of people use these trucks to pull serious weight, seems like yours should be fine.

Is all the maintenance up to par? Any mods like y pipe, headers or a tuner?

 

IMHO you need lower gears.

 

My EX with 3.73s was a dog pulling our 9.5K toyhauler, swapped out for 4.88s and it was a locomotive! Ate up hills like they weren't even there! I'm now pulling an 11K TT and running 35" rubber for an effective ratio of 4.39, still a great tow rig, been up and down everything the East has to offer with no complaints.
Get the gears.
I would also recommend some tunes from Mike at 5 Star, Y-pipe or headers and Y if you want to get the most from the 6.8 2V.

 

make the swap, at altitude can't beat boost.

 

According to Ford's towing guide, your truck is rated to tow 10,800 pounds. 12,500 if you had 4.30 gears. A gear swap seems necessary. I would also do the header/exhaust mods and a 6.0 tranny cooler swap.

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https://www.fleet.ford.com/resources...s/2003_All.pdf

 

3:73 TO 4:30 was the best decision I've ever made. I'm nowhere near the altitude your dealing with though. For me the V10 is the way to go. I came from a 7.3 to the V10. I do have agree with what's already been said, Altitude needs boost!

 

I have a 1999 F250 2wd with V10 and 4:30's and pull a 5th wheel that weighs in around 11k. I love it. Don't know what 3.73's would be like, but the 4:30's are my choice. I would swap your gears and [personally] stay away from the diesel.

 

Yeah you will want the 4:56s to tow that weight especially at higher altitudes.( 6.0l tranny cooler is a must too imo) However with thinner air at higher altitudes the 7.3l will have the advantage do to being forced induction. As the air gets thinner a naturally aspirated engines looses more power than a forced induction engine.

 

I also highly recommend you install a Transgo Tugger shift kit. It's around $100 and you will need to drop the pan. Do a regular tranny flush and have your tranny guy do the install. Makes a world of difference on shifting. For more air, include an AFE intake system as well.

 

If you will be towing heavy WEEKLY then you MAY benefit from the marginally better diesel mileage in the long run vs. the increased cost of diesel fuel itself and the much higher maintenance & repair costs. If you only tow once a month or less, spend the money on the V10 upgrades, and ask yourself why this guy wants to straight swap for a gasser.

I just bought my 2010 V10 to replace a 2000 7.3. Bone stock the V10 is a better daily driver. Even with a 60hp towing tune from the Edge Evolution, I didn't think the 7.3 was that hot-**** towing my 33' 5er around Albuquerque. Oh yeah, if the injectors go out, they're $3,000 a set......if you do the work yourself. A shop will charge you $1,500 to do it for you. I work alot of hours and don't have time to fix my own vehicles (except for oil changes & small stuff), and I can't afford the diesel that I don't need every day. My 2000 is an XLT 2WD also, and I don't have much interest from buyers around here, everyone wants a 4wd.

 

I pull my 30ft TT with my 2001 V10 with 3:73 gears. Loaded weight around 8000# and it would definately struggle in higher elevations. OK on freeway but large hills even make it "scream".

13k is a lot of weight for that truck. The gears would definately help but you are still asking a lot

 

I would agree with Tom's statement. My X has 34" tires running 3.73 gears and it is a dog. I tow a 6k camper and I always have 6 people in the X. 4.30s are on the list when funds are available.

 

Thanks for your input! I did have the 6.0 cooler installed. Also installed air bags and compressor. Bought tunes from Mike; wow..really woke it up. I also had the y pipe changed out. It has more low end power but has changed out the drone for the dreaded flutter at nearly the same rpm range. Hate it. .The shop that installed the pipe recommended drilling and welding a bolt into the y union to change the flow. He's had good results with other rigs. Anyone else tried that?