C20 rear axle options?

[Greubin]

What axle(s) were installed on the C20's w/ leaf springs? It looks like a Dana w/ floating axles. Just curious what I have in the back of my C20 and what ring/pinion options I have.

[trkklr77]

dana 60 or eaton ho52/72

both are full floaters and both were used in 20's

[ND_guy]

Easy to tell the difference They Eaton has a round cover like a F#rd 9" and a one piece housing. The dana has a two piece with a cast iron center section.

[Robert1970C20rstbukt]

The Eaton HO52/72's look like a big truck axle with a 10 bolt cover. The center section is removable and can be interchanged with both the HO52 and 72. Only a couple gear ratios were used in the Eaton: 5.14, 4.56, and 4.10. There used to be 3.90 aftermarket sets availbile, not sure if they're still made. On the Dana axle, you can get gears as high as 3.54 I think, but I'm not too familiar with 'em since both my trucks have Eaton axles.

[Longhorn Man]

the HO72 is a one ton piece, noe 3/4 ton.... but it is almost a moot point since brakes are the main thing between the two.

[Greubin]

Thanks for all the replies and info. I'm fairly sure it's a dana w/4.10's I was hoping to swap gears for 3.73's.

[bob arrington]

you can pick up a later year , say 2004, already has 373 and disc brakes, spring mounts for leafs are already on top, usually run used for bout $200-$300 if you shop arround, hope this helps

[tdangle]

Originally Posted by bob arrington

you can pick up a later year , say 2004, already has 373 and disc brakes, spring mounts for leafs are already on top, usually run used for bout $200-$300 if you shop arround, hope this helps

Will a rear off a 2004 bolt right up or do you need to do mods. I also have a Dana 60 with 4.10 and would love to have posi. Not sure I would want to go to 3.73 or higher because with the OD trans I'm bearly over 2K at hwy speeds even with the 4.10

[bob arrington]

havent got to the buying and installing ...yet. mine is a junkyard parts setup. I wouldnt change your gearing , 2000 rpms at highway speeds still gives a good low end, that and the rear disk brakes was my only goal for the swap. soon as I get one I'll post back. Ive read that you can go to a different ujoint for the drive shaft and that the spring perches may or may not need to be moved.

[gmc684x4]

the 2000 up axles will be wider then your stock axle and will most likely need to be shortened this is the reason most guys swapping axles stop looking at anything newer then a sqb truck

[bob arrington]

Originally Posted by gmc684x4

the 2000 up axles will be wider then your stock axle and will most likely need to be shortened this is the reason most guys swapping axles stop looking at anything newer then a sqb truck

This would be true if he were using stock 72 wheel offsets , the question was for 2005 wheel offset, my rear axle is mocked up at the width of a 2004 using spacers on the stock rear which is approximately 3" narrower than front on these old trucks . my 2004 wheels fit both front and rear wheel wells the same, which was the goal when I find a 2004 to swap out. no shortening required. Thats not quoting most guys, only my own research, hope this helps. btw those old american racing are 12" wide so you would have plenty of room for wider tires..kind of off topic, sorry

[Caddylackn]

A good option for lower gear ratios is the GM 14-bolt. They are floating axle and similar in strength to D60 but are more plentiful in junkyards with cheaper parts for aftermarket support. There are lockers and disc brake kits available.

There are some Dana 61's out there that have gearing as low as 3.08 if you can find one, they were installed on some F-250s during the gas crunch 70's to get better fuel economy.

My truck came with a Dana 60 and 4:11 and I wanted a lower gear ratio so I swapped in a Dana 70U out of a first gen Cummins with a 3:08 limited slip. Diesel 3/4 ton trucks usually came with the lowest gears available for that axle series, so look for axles out of the 6.9 or 7.3 IDI diesel ford pickups, 6.5 Detroit Diesel Chevy, or Cummings Dodge trucks next time you are at the junkyard. Most of these axles came in two widths, single tire or dually, so grab the correct width you need.

[bob arrington]

really good info, many thanks