idi undergeared?

[aiyana7.3]

Ok so I have a 7.3 l idi 1992 Ford heavy duty F250 with the e4od transmission, sterling 10.25 axle in the back and dana 44 axle in the front, 4 in lift, and 35's. We plan on towing a 7000 lb airstream later this year and we live at high altitudes. We are considering regearing it so that it might tow it better.

So my question: is regearing it worth it? how much easier will it make it on the truck and on us? How much of a difference will it actually make? and besides reagearing it and aside from getting a turbo, what else would help? Any input would be greatly appreciated!

 

[79jasper]

You never said what gears you currently have.
A turbo will make the most difference.

Sent from my SM-G900R4 using Tapatalk

 

[dunk]

I'd spend the time and money on a turbo before gears, as with a turbo you may not have as much of a need for changing the gear ratio. I would go the whole 9 though, studs and go ridiculous on turbo like that fancy large ball bearing jobbie there's a thread about here. Doesn't sound like too much more money than one of the off the shelf kits from the big names.

Not sure what gears you have currently but 3.55:1 would be "worst case" for towing and with 35" that should put you around 2000 RPM at 70 MPH, perfect as far as I'm concerned. My goal would be to cram enough air and fuel into it to make it pull your load well before thinking about changing gears. If you have 4.10 that should be plenty of gear to pull more weight than you're pulling now, so again turbo first especially given you're at high altitude.

 

[Shadetreemechanic]

Turbo will be more effective with your altitude.

 

[kuskoal]

3.73 would be awesome with 35" tires! I have to agree with everyone, though. A turbocharger would be more effective than just gearing the truck. By the time you go through both axles (gears, install kit, traction device and oil) you'd be right around where a new turbo would cost.

 

[aiyana7.3]

I don't know what the ratio is for my truck. would a heavy duty 250 with those axles and with the towing package most likely come with one ratio more than another?

 

[icanfixall]

Every differential has a tag from the factory telling you all you want to know in the gears and type of carrier. Read it and post the letters and numbers here. this forum can tell you what you have. Or skip going under the truck and install a turbo. Thats 3 grand you will never regret spending on the truck.

 

[Black dawg]

The biggest tires I have had on my truck were 285s, and with 4.11s mountain towing sucked. I cant imagine 35s with 3.55.
7000 isnt very heavy, but even 4.11s and a turbo wont work very good.

 

[Black dawg]

i guess everybodys "good" is relative, and this may sound harsh, but you guys saying 35s and 3.55s will be ok, have you ever towed anything or towed at elevation or the roads it takes to get there?

 

[Can30Diesel]

I've towed with 373's and 410s, my truck has 285's. The 410's helped quite a bit with the bogginess but if given the choice I'd go turbo first because the 410's with my 4 spd manual had me screaming down the road at like 2500-2800rpm. As a side note, make your your E4OD has a good trans cooler.

 

[SLC97SR5]

Like others have said you really need to verify what gear set you have before throwing money at it.

4.10's and 35's are a decent combo for highway cruising unloaded.

If you have 3.55's your transmission will hate towing that load and it will never be in OD, a turbo won't really help in this situation. You will have more power but probably will not be able to use it on the long, winding grades.

 

[FORDF250HDXLT]

you might have a dana 44 front axle,but your '92 came with dana 50 just so you know.
the axle code is on the door jam.look to see what it is (2 digits) and post it here.though it may not look the best with the trucks lift,you might find the cheapest solution would be to run some devoted towing wheels.if you could source 4 used rims and some 235/85/16 take off's that would gear you down just the same as swapping ring and pinions.better actually as you wouldn't have the huge meats to work at rolling.

 

[dunk]

Also on the front axle... I would never, ever, put money into a TTB front. Any truck I've had whenever the TTB needs work the truck gets a D60, so there's $1k for the front if you can find one with whatever ratio you want, a few hundred more if not. You could do a used turbo (if you can find one) for that price or that's nearly halfway to a new kit just on the front axle.

As for 3.55:1 with 35" and towing light to moderate loads up grades... If a 460 can do it and hold highway speed there should be no reason a similar displacement diesel can't. Granted I've never towed anything at Denver altitudes, but I'd imagine a turbo is the way to fix the thin air problem. Just needs more air and fuel. That's the page I'm on right now with mine, save my pennies until I can afford to cram enough air and fuel in to make it tow as well as my 460 truck. Personally I use mine more unloaded than loaded so I want to keep the 3.55:1 gears for mileage.