I just traded an expedition for a 00 excursion 4x4. Always wanted one, it is an extra vehicle so I plan to play with it a little. The plan is to tow a trail rig with it, but I want it capable enough to drag my jeep back to the trailer if it breaks. Only towing 42 miles in rural Kansas, most the way is 55mph. So what are opinions on tire size and lift for a happy medium? I am not afraid of fender trimming in any way. 5.4 with 4.10s, limited slip rear. Not crazy about spending money on a gear swap but not ruling it out. I suppose the smart answer is probably 33s and call it good but that's a long truck to get anywhere on 33s. I would like a d60 swap, gears, detroits, 6 inches an 38-40s but I can't see towing with that.

 

I agree Junk, 33"s with the stock 4.10 gears will be about as far as you'll want to push that 5.4 with a loaded trailer. Of course anything is possible, how much of your money can we spend?

 

I have a 4x2, f250 v10, to tow with, the Ex would only pull about 6k, 42 miles. I would like to go with 35-37's, but not sure I want to if it will be miserable a gear change, or if it will suck to tow on tires that large stability wise. I take it you don't mind the 35's towing trailers? Would you go any larger?

 

I'm on 4" with 35's, 7.3 and stock 3.73's. Zero issues towing, happy medium all the way around. Obviously taller than stock, without being obnoxiously so or being a PITA to use. 35's are reasonably priced too, pending rim size of course.

You'll find that dingleberry on the transmission likes to hang up on everything. My X sees dirt and trails frequently and the 'berry is bent backwards 90*. Departure angle is a bitch too, ugh. Hitch and tractor hook save me a lot on that end.

 

I run '04 SuperDuty 18" rims with Nitto Dura Grapplers in 305/70R18E (35.28" tall) and pull a 12k 41' TT, tongue weight is 1400+lbs and rear axle weight when loaded gets over 6500lbs. I have no issues at all with these 35"s but I don't think I would be as happy with 37"s in my situation, at that point sidewall height could become a stability issue.
Could you borrow a set of 35"s to give the loaded trailer a test tow to see how bad the 5.4/4.10 combo might be?

 

There you go Tom, I fixed that for you

 

Excellent! I've never had a personalized stepstool before! Now I can get those big 37"s !

 

I have the 7.3 w/ 35" on 18" wheels. It's a noticeable stability downgrade from the stock wheels/tire size when towing. Also, towing w/ 35" and 3.73 sucks, the Ex can't get to overdrive on the slightest incline. And I'm at 2k rpms doing 75mph which is a little hairy when towing w/ these larger tires. But since you already have 4.10's you might be ok, but I know nothing about the 5.4.

 

What the heck are you towing that it's a downgrade? I just moved 2600+ miles towing close to 9000lbs and didn't have a single issue with anything, and I have more sidewall than you as well. You sure you had the tire pressure set right? Small sidewalls = stiffer sidewalls = increase in stabilty. Towing anything significant when lifted without a swaybar will definitely contribute to adverse stability, not bigger wheels. Tow tune made a nice difference though, so that may be a contributing factor. Only had to use tow on long grades though, it stayed in Eco on flats and worked great. 2000rpm at 75 is about average for 35's on stock gears as well.

 

Now you have me curious about the horsepower mods you've made. I'd love to keep my gears if I could figure out how to get more power so I can tow w/ these tires. My TT is only 4000lbs but here in phx you have to go up a hill to get out of here and even the slightest grade I can't get into overdrive.

 

I have had 2- 3/4 ton work trucks in the last 4 years with 5.4Ls, great motors. Towed equipment trailers with no problems,plenty of power and gas mileage averaged about 14mpg, better than my V10 not pulling a trailer.

 

Nothing crazy, typical stuff really... DP F5 chip, 6637 intake, 4" turbo back. That's about it for power mods the rest is just improvements. I went through AZ on my trip, Phoenix and up to Prescott while towing. I'll give you the trip to Prescott was a bitch with the hills in the summer, just watched the trans temp climb uncomfortably close to 220*.

 

And I'm sure you weren't in overdrive. We climb those hills in the summer when it's 106 out. I think you re-convinced me 4.10 gears are the route for me. I need to keep this thing around and running it cool is key.

 

Actually once it got rolling and there was some momentum built up it wasn't bad, it only dropped out of OD on the crazy long grades, and I would manually do so myself anyway - the revs need to be over 2000rpm on the engine to keep from lugging the turbo. You can see EGT's drop significantly on long or steep grades. Overheating the engine is a fairly rare occurrence for the 7.3 when things are working properly.

A 6.0L trans cooler is a far cheaper investment that can be had through several vendors on the forums, and at around $350 is the route I would go first. The stock cooler is an absolute joke. I highly recommend swapping one in first before gears.

 

Already have the 6.0 cooler. I'll tow a couple more times w/ the 3.73 gears and see how it goes. But I hated how anemic it was compared to before I put the 35's on.