how to identify ho72

[txs]

i have one of these but don't know how to tell if it's ho 72 or the bigger one.

[Mark Nixon]

Pulltilbroke or stillsmokin can tell you, I'm sure.
Andrew may pop in later to-night and give you the 411 on it.

Mark.

[stillsmokin]

The HO52/HO72 is an eight lug axle, 10 1/8 ring gear. The external difference being that the H072 has a load deflection bolt in the third member. Ratios were 4.10, 4.57, 5.13, and 5.38 (one odd ratio). There are major internal differences between the H052/HO72 in the pinion area as well.

You probably don't have the 12.25 ring gear H110. The HO72 would fit inside of it, its the kissin cousin of a rockwell 106. They were used in some 11,000 GVW "1 ton" pickup trucks from 1946-1968 and had 10 lug hubs with standard GM 3/4 and 1 ton wheel pilots. They are the largest axle ever used in any production pickup truck (back then they didn't rebadge a C30 "special" since it had the 11,000 GVW). They more commonly found with six on huge pattern hubs in Korean war era GMC slope nose deuces. 6.17 is the common ratio but some P30 step vans had them with 5.43's up until 1981 I think.

I am actually lucky enough to own a 10 lug H110 pickup truck axle. It's pretty unmanageable when it needs moving. It looks like the pumpkin would drag on the ground with 7.50 16's!

Both axles were available in steer versions, The H110 is more common, but the NAPCO 4X4 conversions for 1 ton trucks way back used the H072 in the front.