There is many reasons the E40D does this. Not trying to be a jerk here but there are many, many threads on this trans. Its a fully electronic trans and im not BSin when I say even your third brake light out can effect how it shifts... Run a search read up and if you need more help start your own thread... Lets keep this one on topic!

 

Just checked, GCVW for mine is the lowest of the 97 4x4, manual trans 250HDs: 11,500 Lb. It goes up from there.

5.8, 3.55: 11,500
5.8, 4.10: 13,000
7.3, 3.55: 16,000
7.3, 4.10: 20,000
7.5, 3.55: 12,000
7.5, 4.10: 16000

This is from page 197 in my owners manual. Its a bit over optimistic when it does the math though, it says 0-6200 Lb. for mine which would limit my curb weight to 5,300 when it's over that by about 120 even when I'm not in it.

Those 3.55s really kill the capacity, but they make up for it in fuel milage.

 

And what fuel milage do you get?

 

Current record is 15.6 this summer, same shell station, same pumps 87 octane. I was averaging around 15 before that and it dips to the 12-13s in the winter.

I doubt I could get that with 4.10s, unless I drove slower or something. Hauling obviously dips the milage to, just hauled near my max GVWR with the bed full of concrete, cant wait to see the milage!

 

My buddy consistantly gets 14 out of his 4.10 truck with 285s

 

Thats not as bad as I thought, I have 265's (what's stock 235?), and he gets to legally tow 1,500 more to boot! I probably wouldn't mind 4.10s, especially when slipping the clutch with a full load...

 

Just joined this forum and found this thread very useful as I just bought a 1997 F-250 HD 4x4 5 speed. I like the truck a lot and will be using it for towing a car to the track and firewood. I'm glad to know I have 4.10's in the rear and that I didn't get stuck with a 1998 F-250! Great info!

 

How do you tell which gears your truck has?

 

There should be a marking on your rear end on a differential bolt that will tell you what ratio it has in it.

you can also look on your door jam for your code and then reference your owners manual.

 

Or put a white mark on the drive shaft and one on the tire. Have someone move the truck forward slowly and count how many times the driveshaft goes around for one revolution of the tire. In a '97 F-250 it'll probably be about three and a half times (3.55:1), about 3 and 3/4 times (3.73:1) or a little over 4 times (4.10:1). F-150s might be lower numbers.

Or with a 4WD with manual hubs you can do it by yourself. Lock the right hub, lay under the truck and turn the drive shaft while you watch the U-joint in the left steering knuckle. Because of the differential the axle will turn twice as fast as the gear ratio, so the driveshaft turning a little over 2 times for one axle revolution is 4.10:1 and so on.

You can do this with automatic hubs too, but you need to jack up the left front tire because the hub will lock and you need to let the tire turn or you won't be able to turn the driveshaft.

 

3.55 and 4.10 were the only 2 options.

3.73 did not come back till 99

 

If you look at the back of the passenger side front ttb there should be a bill of material number. 610609-1 3.54
610609-2 4.10
610609-3 3.54
610609-4 4.10
610740-1 3.54
610740-2 4.10
610740-3 3.54
610740-4 4.10

I found that info on the spicer website with a sheet that has all of the spicer numbers for seals and axles and such.

 

Do you have 265/75/16's and do you have any rubbing? I'm looking at BFG All terrain KO's.

 

When changing the oil in the rear end I found the plate behind a bolt as I was taking the rear diff cover off...3.55 for my truck.

eagle275 I'm looking at the same size tires!

 

265/75R16 is basically the same size as 235/85R16. I am running 265/75R16 on my F250's with no issues with factory suspension.