Thought I had a dana 60 actually a 61

[Qumanchew]

Hey guys, I'm looking for opinions on how you would proceed if you were in my shoes. I've been building a rear that I got from the local yard. I've already shaved it, drilled and tapped for arb line, and cut it down to the width I need, however I haven't finished that yet. This morning I go to set up the gears and the ring and pinion don't even touch. The carrier is an arb RD167, should fit 4:10 and down and I'm running 3.54 gears. At this point I'm pretty confident I have a Dana 61. I think I could run a ring gear spacer but not 100% on that.

Sooooo... What's your thoughts? Does anyone know for sure if the spacer will work, and if so would you run it or cut my losses and start over with a 60? 60s around here are $150 ish, so that's not a huge concern at this point.

 

[1969]

Have you found the BOM # on the axle housing? This will help clarify for sure what axle you have.

 

[Qumanchew]

Unfortunately, no. I've gone over it twice but don't see one, which in itself seems odd. The tubes aren't very rust, so it shouldn't have been hard to find. I'm definitely leaning towards cutting my losses at this point.

 

[Yeller]

It takes a ring gear spacer to make it work. There are folks that can help with that. At the end of they day it is up to you.

 

[JB Fab]

If you use a ring gear spacer, you should (IMHO) use safety wire on your ring bolts.....

 

[Broncobowsher]

If you can start over with a correct housing for only $150 I think that would be the better money spent. Not having to deal with a spacer, tolerance stack up, extended bolts that are more likely to back out. Everything goes back to normal.

 

[Qumanchew]

Thanks for the replies. That's what I ended up doing. I bought a 60 for $100 and started over. I found out something interesting weight wise too, the 61 housing weighs 15 lb more than the 60 I got. That's the bare housing with 5" of axle tube, apples to apples. Just looking at them side by side it was clear that the 61 is a heavier casting. That's a bonus for me, because I was already worried about unsprung weight.

 

[Broncobowsher]

For those who don't know about the 61, it came out in the 70's fuel economy era. The original 60 can't take a larger pinion gear than a 3.54 ratio. Dana took the basic 60 and reworked it. I've heard they learned a few things since the original 60 was developed and made those improvements into the 61 housing. That might be the extra 15 LBS? But making a better center section wasn't the goal. New gear sets in the 3.07 and 3.31 ratios were the reason. Before the era of overdrive transmissions, the only way to get lower cruising RPM was a taller axle ratio. (I recall reading that Caddy had an axle ratio of something in the 2.2~:1 when paired to a big inch V8). Since it is a ratio, and the ring gear diameter is fixed, the only way to get a taller gear (lower number) is a larger diameter pinion. The comments of a ring gear spacer to run the lower ratios is possible. The idea is the spacer will move the ring gear mounting surface back to the original 60 position. But functionally not a great idea. The ring gear bolts are highly stressed. They are in a single shear loading condition. Adding a spacer doesn't make it double shear, but stacked single shear. Everything bad about single shear, but multiplied. Tolerance stack up also adds up.

I had a 61 in an f250 with a big block. 3.07 gears and ~32" of tire. You would think an empty truck with a big block would be a tire fryer, it wasn't. But it was a great highway cruiser. Even with just a C6 and no overdrive it was completely comfortable with todays highway speeds. Not great when you need lots of torque from a stop.