dually axle codes (not glove box RPO codes)
 

It has been expressed here that non of the dually's came out of the factory with 373 gears while others have told me they did. The typical ratio is 411 with some 513's. Here are the axle codes for the axles I have. If anyone has any of the these codes and know your axle ratios, please post what the ratios are.

kmc
kum
kmm
kmr
kmc
tfd
rjh

Re: dually axle codes (not glove box RPO codes)
 

I have a D70 with Spicer Axles with unknown ratio How does one find out the ratio? (From what i'm told)

Re: dually axle codes (not glove box RPO codes)
 

Pull the cover and there should be a stamp on the gears, if not just count the teeth and divide ex. 41/11 = 3.73

Re: dually axle codes (not glove box RPO codes)
 

lol i just had it off for a service :S hahaha

Re: dually axle codes (not glove box RPO codes)
 

kum 1975 c30 p30 4.10

kmm 1976 c30 4.10
kmr 1976 c30 4.10
kmc 1978 k30 4.10
rjh 1978 k20 3.73
TFD must be newer, found all the above info in my 73-78 GM parts book.

Re: dually axle codes (not glove box RPO codes)
 

[QUOTE=GM72K10;4366006]kum 1975 c30 p30 4.10

kmm 1976 c30 4.10
kmr 1976 c30 4.10
kmc 1978 k30 4.10
rjh 1978 k20 3.73
TFD must be newer, found all the above info in my 73-78 GM parts book.

Thanks GM72K10, That was exactly what I was looking for.
The RJH (1 ton Dually) and TFD are probably 4.10 also. Does your book list any 1 ton dually 373's by chance?

Re: dually axle codes (not glove box RPO codes)
 

My 85 has 3.73 gears and it is confirmed with the RPO lable in the glove box. Along with the DRW option.

Re: dually axle codes (not glove box RPO codes)
 

[quote=dwragon;4366278]Doesn't list by model (i.e. 30903 w/ dually option, etc) and most of those codes apply to more than one series, I just wrote down the first application I saw. Good Luck.

Re: dually axle codes (not glove box RPO codes)
 

[QUOTE=GM72K10;4366652][quote=dwragon;4366278]

Doesn't list by model (i.e. 30903 w/ dually option, etc) and most of those codes apply to more than one series, I just wrote down the first application I saw. Good Luck.

Thanks again, turned out the RJH 'WAS' a 410, it was the easiest to get to with a jack, and the cover was already off, just the numbers didn't show (Rear end was making a roaring noised so it was pulled, about 30 thousanths wear on the ring.). I marked the drum and the pinion and turned them. Two turns of the pinion equalled one turn of the drum. Then I checked the others I could get to, they were all the same. Pulled the rear cover off my HO72, had 7 & 35 on the pinion, so I guess it's a 513, too lo for me so its gotta go. Inside looked great though, really clean red oil.