Dana 80= Dana 80, right?

[tpass]

My 01 3500HD has a dana 80 rear with 5.13 gears... they are short to say the least. The only other option was a 4.63.

I am just spitballing the idea of going to something like a 4:10 and I see dana 80 gear sets on summit in all sorts of ratio's, any reason why something sold as a dana 80 wouldnt fit?

This is all just me "thinking out loud" I probably never will do the swap but was curious about it, I am Dana illiterate.

 

[stutaeng]

Are you doing a lot of highway miles? What are your RPMs? You have the 8.1 liter, right?

 

[tpass]

Are you doing a lot of highway miles? What are your RPMs? You have the 8.1 liter, right?

No its just an around town rig, but it just feels like its stuck in second gear lol. like I said.. most likely won't ever change them out, but was just curious about DANA 80's

yes the 8.1.

 

[DonYukon]

Im confused by the post . so you have 5.13s??? on a highway truck? which would make sense for you to want to downsize. or are you wanting taller gears for a highway truck?

Either way there is few times you would benifit from a 5.13 gear in the offroad world those gear sets are used for bigger tires like 38+ and its a good crawl gear. past that as far as Daily / tow rig with a diesel the best would be a 3.73-4.10

 

[stutaeng]

I've never driven a C3500HD, but always thought they were cool...

Why do you say it feels like it's stuck on second gear? It doesn't accelerate? Or your RPM gets so high that you don't go any faster?

What size outer diameter are those 19.5" rims anyway? Probably need to do that gear calculator for your transmission, tire and differential.

@someotherguy has run these trucks on wreckers. Maybe he can shed some light on the topic.

 

[454cid]

I would think Dana 80 gears are Dana 80 gears.... just make sure tere is no carrier split. I know there are some axles where a carrier change needs to take place too.

Checking out one of the gear ratio calculators online would be a great idea.

You've got more wreight in the HD than I do in my k3500, I'm sure. 4.63 might be fine around town, and maybe you could just swap the whole axle?

 

[someotherguy]

The HD's run those gears because they're designed to pull lots of weight, plus they have 32+" tires (225/70/19.5) The only axle ratios offered across the entire run of HD's were 4.63 and 5.13, so the only direct swap whole axle - going to 4.63 - would only drop your highway RPM's by about 400 or so, not likely worth the investment.

You could go to 4.10's, sure, which would drop your RPM's by about 750. So instead of running 3750 RPM at 70 MPH, you'd be right at 3000. That's using the measurement of 32.2" on the tire. You'll give up a little bit of the usability of that HD, though. If your're not using it near its design margins, you'll probably be OK.

You wanna know for sure if a particular gear set will fit your diff? Call someone in the biz, like Randy's. They sell 'em for Dana 80's and should know all about it.

As far as carrier split, it looks like 4.10 and up is the "split" so your carrier should be fine as long as you don't go below 4.10.

Richard

 

[b454rat]

IIRC Dana is a Dana. I’ve heard swapping diffs from Dodge for 4.10s or 3.55s, but want to say the splines are different. I was gonna build one couple years ago, looked at options n what not but sold truck before did anything.

 

[DonYukon]

The HD's run those gears because they're designed to pull lots of weight, plus they have 32+" tires (225/70/19.5) The only axle ratios offered across the entire run of HD's were 4.63 and 5.13, so the only direct swap whole axle - going to 4.63 - would only drop your highway RPM's by about 400 or so, not likely worth the investment.

You could go to 4.10's, sure, which would drop your RPM's by about 750. So instead of running 3750 RPM at 70 MPH, you'd be right at 3000. That's using the measurement of 32.2" on the tire. You'll give up a little bit of the usability of that HD, though. If your're not using it near its design margins, you'll probably be OK.

You wanna know for sure if a particular gear set will fit your diff? Call someone in the biz, like Randy's. They sell 'em for Dana 80's and should know all about it.

As far as carrier split, it looks like 4.10 and up is the "split" so your carrier should be fine as long as you don't go below 4.10.

Richard

had no idea that those were the only gears offered in the HDs are we talking 3500 only or 2500 as well??? Im assuming the gear made up for the lack of power back then? 5.13 is a massive gear for anything unloaded to be economical by aany stretch. comparing apples to oranges here but my new HD only has 3.73s and has a max tow rating of 18.5k as a gasser and I think the Diesels will tow almost double that with 3.42s but obviously they have double the input torque.

 

[454cid]

had no idea that those were the only gears offered in the HDs are we talking 3500 only or 2500 as well???

You're thinking pickups. The 3500HD is a 15,000 GVW cab&chassis only availble in 2wd from GM. All 4x4s are conversions that replace the factory i-beam (solid axle) with a driven solid axle. They have 10 huge lugs in the rear and 5-huge lugs up front.

The 3500HD's were typically tow trucks, box trucks, or small dump trucks.