Ok, I was looking at this truck tonight, 6.9, 4speed. 2wd, and I looked at the axle code on the door sticker, and would swear it was a H2, am I seeing things, or is this right? If so, what ratio is it? I am looking at it because my sister is looking to replace her current wreck of a truck. It has a dually conversion done to it, I was wondering how safe and strong those hub extensions are, and anything I should know about this type conversion. The end of the hub is flush with the rims. The major purpose of this truck would be to pull a 5 horse slant trailer and haul large square hay bales. It has overload springs that are heavier than my 250 4x4, and the rear sway bar like a one ton. Thanks for any info, would be good to have a response quickly, as I need to report to her before she buys a different truck that may be more trouble than I want to deal with.

 

I don't know of an H2 axle code. H-code axles are in 1/2-tons, B- and C-codes are for 3/4-tons, and D-, F- and W-codes are in 1-tons. The letters all designate a limited slip differential. The number behind the letter designates the ratio. '8' is 3.08, '9' is 3.55 and '5' is 4.10. There is no '2' that I know of in a limited-slip (alphanumeric) code. Open diff codes are 1, 2, 3, 4, 6, and 7 for the first digit in a 2-digit code where '1' is for 1/2-tons, '2' and '3' are for 3/4-tons, '4', '6' and '7' are for 1-tons. The way you describe the truck, it sounds like a converted 3/4-ton or SRW 1-ton, which typically only come in two ratios: 3.55 and 4.10.

As far as the 'dually' conversion, personally I would rather have a real factory-made dually, or at least a truck that had been converted to dual rears by swapping to a dual rear axle from a real dually truck. As long as you're not going over the original GVWR and rear GAWR of the truck, as stated on the door sticker, the aftermarket dually hub extensions may be ok. The aftermarket extenders put the weight out beyond where the factory designed it to be centered on the factory hub, and also increase stress on the original wheel lug studs, as the extender acts like a lever. They are for increased lateral stability and do not contribute to increasing the load-carrying rating of the truck.

If she needs a dually to haul her trailer and hay load, she would be better off waiting untill she can find an actual dually truck. If she can get away with a SRW truck to haul it, maybe this truck would be good for the job.

 

I haed concerns with the extenders, once I realized it was a 250. The badges caught my eye first, then the sunken axle. I feel she could get by on a srw, but she likes the stability of the duals. Her trailer is steel framed aluminum sided and fiberglass roof. I'll have to crunch the numbers to see where she's running. The other truck is an ex dot sander truck, has the Cat 3208 and allison trans, don't know on the rear axle for it. I have to add a sleeper, flat bed, and undo all that they did to make it a plow and sander truck. Thanks for the info, I may look again, and I may blow it off. Have to think about it a bit.

 

Wow, that plow truck sounds like it would pull just about anything with a 3208 CAT in it... I somehow doubt that it will be able to keep up with highway traffic with the low ratio it likely has though. Does sound like a cool pulling truck!

 

That's what my concern is too, my wondrous brother in law thinks it will be high geared, he couldn't even answer if it was a 2 speed axle or not. I'll be checking it out in person before I'll ever give it the ok. He also thinks since it was DOT that it means well maintaned...

 

H2 is a Ford 9" 3.50:1 Limited Slip for 1980 only.

You are probably seeing things. Perhaps somebody changed the cab at some point?

 

It all looks original, if I get back by there, have to take another look. Now it's bugging me!!! It has the same GVWR listed as my 250, so I doubt it was changed.

 

I was almost right, G2 is the code.

 

If my memory serves, anything with a letter in the code means LS or posi.

John

 

yes, but gear ratio? I can't find this one on the list, and it isn't in my 86 book.

 

I would look at the axle itself and find the ratio tag and go with what's on there, if it's still on the axle. You can also figure out the ratio mathematically if the truck has a tach, the speedo is accurate, and you know the tire size. Drive in high gear, or whatever gear is 1:1 in that truck at a constant speed and record the engine rpms. The equation for figuring gear ratio from mph, rpms and tire size is:

GearRatio = (RPM x TireDia) / (MPH x 336). Tire dia is in inches. 235/85-16 tires are approximately 31.5" tall.

 

G2 = 1984/1985 4.10:1 6300 lbs Dana 70U Locking

 

Thanks, that's what I figured, wanted to confirm.