I have a 1992 F-350 Crewcab dually with zf5 and 7.3 IDIT. I do a lot of empty interstate driving and don't like my rpms vs. mpgs with the 4.10 rear end. Did ford make a 3.55 dually rear end that will interchange or preferably just a gearset that will fit the stock housing? I think I have the Dana axle. If I can just change the gears, can it be gone with rear end still in the truck? I do very little in city driving and am not concerned about acceleration as I know it won't be as good with the 3.55s.

I have researched this and haven't found a definite answer let alone what I should be looking for.

 

Well first off most likely you have a sterling 10.25 rear end. They did make a 3.55 rear end that swaps in but there rare so the easy answer would be a gear change but that would require removal of the rear end and a complete rebuild but any decent differential shop should be able to do it (especially 4x4/off road shops)

 

I think the 92 dually rear end was a Dana 70 or 80? The answer to your question is, yes the gears can be changed, but it is not really a home project. They are hard to dial in correctly. A rear end isn't very hard to change, if you are looking for diy, I would try to jy the axle with the gears you want and swap it out.

Good luck,

Mac.

 

funny i was just mentioning this,this morning on oil burners.
your rear axle is a sterling 10.25 as mentioned.yes you can swap in a DRW pickup axle with a 3.55 gear set.you'll need to stick with the '92 or older axle.it's the first gen sterling.you wont find a drw pickup axle in the 2nd gen sterling (93-97) sporting 3.55's. (it doesn't matter what yard you find claiming to have a '93+ sporting the 3.55's/if you have them verify it,they'll find 4.10's or that it's really a cab n chassis.trust me brother.i spent enough hours searching for everyone lol.)

these axles are pricey as a rule though and you may be just better off getting a quote for a shop who has the required tools for a proper gear swap as well as a quote for another dually pickup axle sporting 3.55's.
i recently bought a drw pickup axle,1989 w/ ring tone for abs/vss, non LS,first gen sterling w/ 3.55's for $750 shipped and it needed a seal on one side (so far) completely new brakes w/ all new hardware and it also needed new drums pushing the price upward to the 900-1k range.

 

In my 86 F350 dump truck, I bought a used oem 4.10 ring and pinion off ebay for $50. Swapped them in, backlash felt about right so I ran it. No problems yet... maybe 10-15k miles on it.

 

Gear swaps are pretty easy for even a diy mechanicly minded person. Its not black magic.
Read up and go for it. If you get a good wrecking yard set they may have a can of shims to loan you, otherwise buy a side bearing shim kit from Randys or one of the other drivetrain companies. I have done many sterlings and have only had to change one pinion shim pack. The rest came in VERY close.

 

Just a suggestion, but maybe get another vehicle for your daily driver? That truck you have there is the biggest beast you can get in pickup form and it's made for hauling, kind of redundant for empty interstate driving.

I had almost the exact same truck, see siggy, and it's more than the gearing that's hurting your mileage, but the weight of the truck and the fact it's a dually. With a dually you have 50% more road restriction over a regular truck thanks to the extra tires.

One thing though, if you're still sporting the 215s in the rear go to 235s, that'll help you a little.

Myself, I didn't notice an RPM issue with the 4:10 in overdrive, it handled 70-75mph nicely. But did drink a lot of fuel. But I still got 50% better mileage than any 460 I've seen.

 

As far as I know the only specialty tool you need to do a regear is a dial indicator and you can get those at harbor frieght for cheap. Shims are obtainable and so are pinion and ring gears. Find a general step by step write up on regearing ( probably on a off road forum) and use it. Shouldn't be that tough just take your time and think about things before you start pulling it apart and take lots of pictures to use as a reference

 

Just get a new gear set kit for $350 and be done with it. It will come with new ring and pinion gears, new bearings, new shims, and a new crush sleeve.

I don't see you having a Dana axle. They stopped putting them in trucks in the late 80's unless you had a reason to have a heavier duty axle. The tag on the differential will tell you for sure though.

I just got done doing this exact swap, on basically the exact same truck. Mine's a '94 PSD, 5 speed, crew cab dually. I don't tow heavy enough to justify the 4.10's. I got a used factory gear set (any sterling gear set will work, but there are differences in the pinion depth between 1st and 2nd gen sterlings). I had never done a gear swap before, and it took me a few days to get it right, but in the end, knowing what I know now, it was stupid simple. Nowhere near as bad as I had hopped it up to be in my head.