So let's talk gears

[kuskoal]

When my Centurion makes it's way down to lovely San Diego, I have to address the early 10.25 pinion problem. Should make it down fine because it will be nice highway cruising.

So here is the question; is 4.10 ratio gears and 37" tires going to be enough to move this 8000 lb boat around at 65-70 mph? Or would, say 4.30 or 4.56 be a better solution? I can look at charts on powerbands all day, but I figured I should ask the experts before buying my replacement gearset!

 

[icanfixall]

Really not sure but I'm watching answers to this interesting post. I'm planning changing my 3.55 to either 3.73 or 4.10 gears. I have driven many hundreds of thousands of miles with the 3.55 gears. My only complaint is the take off from a dead start. Once moving I have no issues with the gearing. Too bad I don't have a US gear splitter. Then I could split the first gear.

 

[redneckaggie]

http://www.grimmjeeper.com/gears.html

If I got everything correct 4.10 would put you at 1850 rpm at 70, imo that is a little low for powerband and pulling but would make for some good mileage

4.30's would make it around 2000 at 70

4.56's would put it around 2100 at 70

I would say that If I planned on many hills with a load I would go with 4.30 if you are determined to keep your 37s, if you are only empty most of the time go with 4.10 and get a good cooler for the tranny for when you pull.

 

[Oog]

I would do a gasser zf5 swap. I was quite happy with 460zf/4.10s/37s

 

[kuskoal]

Planning on 37's or 38's next time around. I am using novak's gear calculator and it put me at 2032 rpm. Weird! Would 2032 rpm be "enough" to cruise down the freeway with this big brick? Egt wise, Don't want to lug it around much. Or downshift a lot to maimtain speed.

The lift and tires will stay, it came that way and will work nice for exploring the sand/rocks around here and the Reno, NV area. Not going to tow too much either, maybe a little trailer to throw camping junk in so I can sleep in the back.

The zf5 swap will be way later in the game. I rebuilt the e4od and put all the updated stuff in it.

 

[typ4]

My dually was 410, c6 with gear vendors, 235/16, took right off with an na7.3, switched to 373, feels the same but the convertor is sloppy, Im putting in a low stall and will report back. I think you will be fine because im going to be hauling a camper and trailer with sandrails. 14k total gross. My 91 4x4 does it just fine,with 355, BUT it has the torque cam and modded turbo.

 

[chris142]

Imo 37 inch tires +8000 lb boat+70 mph is a recipe for a crash. If not a crash a big speeding ticket in ca .

Ok carry on.

 

[Oog]

Nvm youre e40d. My bad

 

[franklin2]

I have a zf 5 speed, 35 inch tires with 4.10's. I just got back from a trip hauling a 7000 lb skid steer. It pulls it the best in 4th gear, it would do ok on flat land with no headwind in overdrive, but it's marginal, and I do not have a turbo. But everything is good running empty. I think if you gear too high you will be unhappy unloaded, but if you do not run much unloaded I guess that would not matter.

 

[FORDF250HDXLT]

so running 37's with 4.10's is like swapping to 3.55 and running oem tires (so close it's not funny) of course that will be more gear than required to just simply drive around the hwy with and lightly tow.it's not like your gearing upwards of 3:08 rang or anything.which would still actually be fine with the grunt of the diesel,and just hwy driving.
i run chip truck at 1350-1500 rpm's all the time.there's no need have them racing for power like a gas truck.

Imo 37 inch tires +8000 lb boat+70 mph is a recipe for a crash. If not a crash a big speeding ticket in ca .

Ok carry on.

i think he's just referring to his truck (which weighs 8k lbs) as a "big heavy boat" not actually towing an 8k lb boat.

 

[kuskoal]

So the 4.10 ratio should he suffice for a turbocharged 6.9 putting around the freeway? I know its about the 3.55 ratio, just wondering about the need for extra rpm for by the increased wind resistance. Since it checks out by the heavy haulers, I will start piecing the parts list together!

 

[burt]

I have run 35 mudders (toyo mt 315 75 16) on both my trucks with 4.10 for many years and haul heavy in pretty steep roads and really have considered gearing up more often then down (numerically down more often than numerically up). I dont think you'll be under geared at all.

 

[icanfixall]

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This is what I'm turning at 75 and 85 mph in double overdrive with the E4OD and the gear Vendors. Stock tires and 3:55 gears out back.
My final drive ratio is 1.96. All you hear is the air rushing by the cab. No real engine noise at all.

 

[kuskoal]

Wow! I needs to get my hands on the bw1356 adapter for my gear vendors! I found one with a 2wd c6 adapter.

 

[redneckaggie]

4.10 gets my vote if you arent towing much