chugger

Gentlemen, I recently busted the exciter ring on my 91 3/4 w-250. no biggy, pulled the ring canned the abs. good to go! or so i thought. Yesterday morning had a thud and then a thump thump thump from the rear. Thought maybe u-joints.... No luck, pulled rear diff cover and had a bowl of metal cereal waiting for me to fish it out of the bottom of the pumkin. Called to get prices on replacing the ring and pinion... Yeah right. I had one guy try to tell me that the cheapest he could get a ring and pinion for was (that's right just the ring and pinion) 365$ and a grand total of 11300 bucks. So I am looking at alternate routes, just swapping out the entire rear is looking a lot easier. What is interchangeable and what will work with a little modification?? Gear ratio is 3.54 by the way and I am in the cheyenne area. Thanks

wannadiesel

D70 (of course) - one off a 2nd gen would be a nice little upgrade because you'd get outboard drums.

D80 (later 2nd gens) will take a little work fabbing shock mounts and the driveshaft ought to lose an inch. But it's a stronger read, and the last year had discs.

jimbo486

a friend of mine has a '94 2500 and says he's got a dana 80 in it. possibly swapped by the previous owner? and can you elaborate on outboard drums, dave? don't think i've heard the term before. as for the shock mounts on the dana 80 from later 2nd gens., couldn't the shock mounts from a stock 1st gen be used in the same place on the dana 80?

comptz

I think outboard brakes is when you dont have to pull the axle out to get the drums off. So if my thinking is right all you have to do to work on the brakes is just pull the wheel off and pull the drum off without pulling the axle

jimbo486

ohhh. that would make the task a lot easier!

JustRamIt91

outboard drums, meaning just pull the drum off with two hands, or a screw driver and a couple strikes with a mallet. Instead of integrated drums?(never heard this one either) which you have to remove the axle and floating hub (8 bolts and special socket for bearing nut) off in order to work on the drum and shoe assembly.

The shock locations on the rears might be in different places so you would need to cut the old ones off and weld them on the new rear. (meaning YES and it would be easier than making your own)

chugger

awesome guys, thanks for the input. Is there any difference in the overall length on these?? (over all length from outer hub to outer hub or wheel mounting surface????

Rick 12v CTD

I think there is? I think the dana 80 has a slightly wider stance. Let someone else chime in before you take my word for it. I read somewhere that it was slightly wider but I can't remember where I read it.

I personally would actually be for a slightly wider rear (I now what you crusty old men are thinking, get your minds out of the gutter). I don't know if anyone else notices but the Dana 70 rears in our trucks have a more narrow stance than the front of the truck by a little bit. It's so annoying as far as looks go. I know it really means little to nothing but to me, it's an eye sore. I like symmetry.

12valve@heart

Here are 2 threads that you may want to read. One discusses the D70/D80 and the other mentions the Chevy 14 bolt.

https://www.dieseltruckresource.com/...ght=bolt+chevy

https://www.dieseltruckresource.com/...ght=bolt+chevy

jesussaves

there is a d70 from a 2nd gen close to me on craigs list but he doesnt know if its a lsd? How can you tell? And whats a good price to offer him?

Old-stuff

I just checked my 1990 w/D70 vs 1995 w/D80.
1990 width ~ 65",@wheel flange..... Center of axel to C of ujoint ~ 15 1/2"
1995 width ~ 70",@wheel flange..... ~ 17 "
As Wanna said you will have to shorten driveshaft w/D80. Plus look out for different size u-joints.
D80 or D70 width will be determined by vehicle it came from
My 1995 3/4 ton came from the factory with D80, It shows that on the lable under the hood.( Stock with 5 speed is what I've read )
Ray

JustRamIt91

You can tell by looking inside, Spider gears gives it away. Or If you can raise both rear wheels, then turn one by hand, watch the other one. If it turn in the same direction it's a LSD, otherwise it'll go the opposite way.