C-50 2 speed gears

[regan wilson]

Are there any 4.00 series gears for a 2 speed rear? Sorry the image is sideways. Photobucket wasn't cooperating.

[CarolinaHD]

Yes I believe there were 3 options;
4.xx/6.xx
5.xx/7.xx
6.xx/8.xx

[regan wilson]

Carolina is there any clarification on what 4 and 6 is? I know 6 and 8 is low low. Anyhow I'd love to use this rearend in the future but I need some Diesel friendly gearing. Not Detroit friendly but Cummins 2300 to 2500rpm at 75mph friendly.

[CarolinaHD]

Looks like the gas had the option of
6.5/8.85
7.17/9.76

You want a 3rd member from diesel,
4.86/6.61
5.57/7.59

[regan wilson]

Thanks. The Diesel gears are still pretty steep. Of course the speed limit back then was 55 and everything was underpowered. Lol. If I use a Dana 80 instead maybe I could put an old splitter on the shifter just for looks.

[C10 - C90 Bill]

Before I got my '67 7500, the previous owner switched it from a Toro-Flow to a 6V-53 Detroit. He said after the engine change, the truck wouldn't go any more than 45 MPH. I don't know what he got the replacement rear from, but it brought it up to 60.

[CarolinaHD]

Better option might be the bigger dana axles (dana 110?) that came in 4500/5500 and f450/f550.

Should have gear ratios of 4.30, 4.88, 5.13

[regan wilson]

I'll have to stick with the Dana 80. Even a 4.30 will be a little steep. If I end up with a NV5600 behind a 5.9 Cummins low gear is more than enough. While were at it does anybody have a NAPA part number for rear wheel cylinders? Thanks.

[jumpsoffrock]

I found a 15,000 lbs 4.86/6.61 diff on ebay in 2015 and installed it. Highest gear I could find. Runs fine but it dropped my GVW 5,000.

That's been tested a few times.



Honestly I just realized I don't know how to prove which GVW it is or isn't, I guess it cold be the full 20,000

J13 : 15000-LB. 2 SPEED AXLE 4.86/6.61 RATIO

http://outintheshop.com/options.html

[Campbel45]

Regan,

If you really wanted to keep the 2-speed, you could install an auxiliary gear box. This would give you overdrive. You might want to look into driveshaft speed at some point. I picked up a spicer 7231 to gain a overdrive for my C50. You'll find that some C60's already have this auxiliary transmission.

Another option is exactly what your thinking about, swap in a different axle. You could probably find an Eaton 19060T (19=19,000lbs, T=two speed) under some medium duty trucks.

I see alot of internationals getting parted out. These usually have an N175 rear end them (17,000lbs, single speed) with a gear ratio 3.90, 4.10, 4.44 (they come in many different ratios).

With both of those axles, you'll probably find them fitted with disc brakes if that matters to you.

[regan wilson]

Thanks for the replies. The modern 2 speed rears sound like a good idea. I'd love to keep one whether I need it or not. I've been having fun driving around on our property shifting gears. Now the no brakes deal not so much fun. Back to the transmission topic. I know you can adapt just about anything together. I don't know how they would hold up behind a 800 to 900 ft lbs of torque.

[regan wilson]

It looks like I was wrong about the gears. I used a gear calculator and plugged in all the info. If I used a 9R-22.5 tire that is 38' tall with a 4.86 gear it would work. That is with an NV 5600 6 speed OD ratio is .73. It is almost dead on with my Dodge Dually. The calculator reads 79.6mph @ 2500rpm. Now the big question is where in the world would I find a drop in replacement for my rear?