GM or DANA or does it matter?

[Lester]

Which is the better rear end under a 1 ton K30 or C30, GM or DANA?

Need to swap mine out and I have one of each that I could replace it with.

Seems like a straight swap either way as far as driveshaft, springs, brake lines and shocks are concerned.


Thanks.

[1FaastC10]

14 bolt full floater all the way. parts are everywhere, and they're cheap.

[mike reeh]

GM 14 bolt FF.. damn near unbreakable and they're everywhere

[Lester]

The DANA is out of a 78 dually C30 and the GM is out of an 89 C30 dually. If I use the 89 GM, think it matters if it is going into a 77 K30?

Think of any fitment issues? Does not seem to be just looking at them.

Thanks.

[toytruck]

pick the one with the best gears. 3;73 would be good.

[1tonswb]

Cant go wrong with a 14 bolt.

[mike reeh]

2WD axles had different shock mounts than 4WD.. So the length of your shocks might be an issue.. Im pretty sure they're in the same place but the 4wd mount is a couple inches higher.. In other words, the 2wd mount hangs down below the axle tubes quite a bit. If the truck is lifted, you should be fine since you will have different shocks anyways...

DEFINATELY go with the 89 14 bolt! If it has a gov-lock carrier, then you're stoked.. They're pretty good, and if not, the detroit is a real easy and inexpensive mod (it installs into the stock open carrier)... Since its from a 1 ton, its almost HAS to have 3.73, 4.10, or 4.56 gears


let us know what you choose

mike

[edit] regarding fitment issues, are you 100% sure that the donor axles came from a true one ton truck, and are going into a true one ton truck? because the spring perches are located differently on 3/4 vs. 1 ton........ Other than that they should be identical

[Lester]

The donor trucks are both real C30's. I pulled both axles.

Both are 4.10 axles which match the DANA 60 in front on my K30 (real).

My experience with GM FF axles is from 1 ton Van's, G30's, and I NEVER had one of them break, 2wd or 4wd, but they were all SRW axles.

All my experience with dually rear ends is with DANA's and I never had one of them break.

I was leaning toward the GM to start with because its newer, the frame on the truck isn't rusted at all, but it is bent. Then somebody I know said they wanted the DANA 70. So before I sold the wrong unit I thought I'd make sure, I don't really want to do this twice. Both axles are open. Have not seen a locking dually rear end lately.

Thanks for the tip on the shock mounts, had not noticed that before. I will be using the Skyjacker 2" lift kit which includes spring, hardware and shocks to replace the current set up.

Why am I doing this? The original owner of the K30 broke the original rear end at the housing and replaced it with a salvage yard unit just before I bought the truck several years ago... all DANA 70's are the same, right??? Not so. This DANA vibrates above 40. Took awhile to figure out why. This unit is from a 1966 Ford 1 ton 2wd stake truck and the pinion shaft is offset more than 6" further to the passenger side than a GM or DANA made for a GM. The driveshaft is out of alignment left to right and top to bottom quite a bit. PLUS Ford axles in 1966 apparently did not have shock mounts on the tube they were on the spring plate... no rear shocks on the truck. No problem with 15 leaves in each stack until you got it loaded...kinda bouncy. Anyway changing rearends and springs should civilize this truck a little bit.

Thanks for your advice.

[Lester]

There are two dually rear ends one for the cab chassis and one for the pickup, DANA or GM. Both vehicles are called C30 or K30.

Rear ends in the unit are different widths, with the pickup being the wider unit.

Anybody happen to know if there are more differences than just this?

The DANA is pickup dually, I have the entire truck. However I don't know if the other unit was a pickup or not because I only have the back half of the truck left after it was hit. It appears it might have been a stretched cab chassis, but the rear ends look just alike, except its a GM rear end.

Any site have rear dimensions posted for DANA and GM rearends for reference?

Thanks.