Broken rear axle: Should I stay with Dana 35 or upgrade to Dana 44?

Jeepin’ said:
OK...so the deal is done and now I just have to go pick up the Dana 44 rear/3.73 AND Dana 30 front/3.73. My question now is, my son’s Jeep’s PO did tell me he had to replace the drive shaft within the past 2 years. He said he had it replaced with a “heavy duty shaft” with eliminator as the previous shaft didn’t have one. Looking at the angles the previous shaft must have been in (fairly steep), should I assume there could be damage to my son’s Jeep’s transfer case as well? The reason I ask is because the seller I’m getting the Dana 44 from has the transfer case available too...
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The Tcase should be fine. The swb TJ does not take much lift before needing driveline modifications, about 3" and over you should be using a slip yoke eliminator and double cardan driveshaft. There are other ways to do it but they are "workarounds" to the correct way.

Going from the Dana 35 to the Dana 44 will need some driveshaft changes. Shortening and possibly a ujoint change. You will see all that once it is mounted.
 
Rob5589 said:
The Tcase should be fine. The swb TJ does not take much lift before needing driveline modifications, about 3" and over you should be using a slip yoke eliminator and double cardan driveshaft. There are other ways to do it but they are "workarounds" to the correct way.

Going from the Dana 35 to the Dana 44 will need some driveshaft changes. Shortening and possibly a ujoint change. You will see all that once it is mounted.
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I forgot to mention the reason the PO had to replace the drive shaft was because he said it broke. The Jeep has at least a 6” lift.
 
Rob5589 said:
It surely must have a sye/dc shaft. Can you post up pics of the rear of the tcase and drive shaft?
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It’s on the rack in a shop that’s closed today, but these are pics I took in a parking lot when I was test driving it before I bought it. And yes, now I realize how ridiculous that Dana 35 looks attached to those 35”s...

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Jerry Bransford said:
Your rear CV driveshaft confirms a SYE has been installed.
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I sure wish I’d been in this forum to post these pics before I bought it...:smash2:
Am I right in thinking the Dana 44 I’m getting from the ‘01 Sport with towing package will give me the option for running discs instead of the drums I currently have?
 
Jeepin’ said:
Am I right in thinking the Dana 44 I’m getting from the ‘01 Sport with towing package will give me the option for running discs instead of the drums I currently have?
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DIsk/drum brakes are the same option for your Dana 35 and the Dana 44 you're looking at. You can also transfer your existing drum brakes to the Dana 44, they bolt on the same as they do on your Dana 35 which would be easy. You wouldn't even have to disconnect the brake line.

Don't be Jonesing for rear disk brakes hoping for better braking, properly functioning rear drum brakes brake literally just as well as rear disk brakes do. The only benefit to converting your rear drums to disk is that disk brakes are easier to work on. Whether it's drum or disk, the brake system's proportioning valve is there to reduce brake line pressure to the rear brakes so they can't brake up to their full potential. Front/rear braking bias is set by the proportioning valve to about 70/30. That's because rear brakes would lock up too easily under hard braking due to the weight coming off the rear tires during hard braking due to weight transfer. Locked up rear brakes cause slides/skids/etc. so the rear braking force has to be reduced substantially to reduce that possibility.
 
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Jerry Bransford said:
Oh wait temporary confusion, I was just saying a SYE is installed in the vehicle in the photos.

DIsk/drum brakes are the same option for your Dana 35 and the Dana 44 you're looking at. You can also transfer your existing drum brakes to the Dana 44, they bolt on the same as they do on your Dana 35 which would be easy. You wouldn't even have to disconnect the brake line.

Don't be Jonesing for rear disk brakes hoping for better braking, properly functioning rear drum brakes brake literally just as well as rear disk brakes do. The only benefit to converting your rear drums to disk is that disk brakes are easier to work on. Whether it's drum or disk, the brake system's proportioning valve is there to reduce brake line pressure to the rear brakes so they can't brake up to their full potential. Front/rear braking is set to about 70/30. That's because they tend to lock up to easily in the rear under hard braking due to the weight coming off the rear tires during hard braking due to weight transfer. Locked up rear brakes cause slides/skids/etc. so the rear braking force has to be reduced substantially to reduce that possibility.
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OK, yeah that makes sense. So the “disks are easier to work on” factor isn’t really that big a deal. Is there anything else you can think of that I should do while I have it up changing out both axle assemblies?
 
Jeepin’ said:
And yes, it’s matching 3.07.
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OK so I am the 3.07 guy, but 35s??? yeah, no.

I drove 33s, 3.07s for years, no issue for me because this was my DD and I had no problem not using OD on the highway. But the bigger the tire, the smaller the engine, ie SE, the more critical the ratio.

I had Trans Ams in the 1970s, one was a 455SD with a 4 speed and a 3.55. A rocket ship. The next was a 400 turbo 400 with a 2.97 ?? It was an all day cruise at 100 mph. Point is, a 4.0L will barely turn 35s thru 3.07s. AND the torque loading will eventually break something.

That said, 3.07s, 33s 4LO, a rocket ship on the forestry roads. It would hit 60mph in 5th gear.

But the reason you broke an axle is the 3.07s, not the Dana 35 if yer driving it on the street. Price it out, but I'm betting you can find a Dana 44 or a Ford 8.8 with 3.73s for less than a new axle and regear.

But DD ??? Why not also drop down to 33s ?
 
billiebob said:
But the reason you broke an axle is the 3.07s, not the Dana 35 if yer driving it on the street.
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Higher axle ratios like 3.07 deliver less torque to the axle and thus its shafts. His 3.07 ratio was not the cause of his broken axle shaft. What broke it is the leverage the larger diameter tire had against the axle shaft.
 
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You measure torque at the tire. Torque is generated at the engine. Anyone who rides a bicycle understands a taller gear will bend the bike frame as you stand on the pedals leaning over the handle bars. BUT change gears, lower ratios and suddenly the stress on everything from your legs thru the bike frame becomes insignificant. He broke the axle because the stress between the engine and the ground exceeded the strength of the axle.

Flat out, a lower rear end ratio would have reduced the stress. Everything is a compromise. Just like riding a bike.
 
billiebob said:
You measure torque at the tire. Torque is generated at the engine. Anyone who rides a bicycle understands a taller gear will bend the bike frame as you stand on the pedals leaning over the handle bars. BUT change gears, lower ratios and suddenly the stress on everything from your legs thru the bike frame becomes insignificant. He broke the axle because the stress between the engine and the ground exceeded the strength of the axle.

Flat out, a lower rear end ratio would have reduced the stress. Everything is a compromise. Just like riding a bike.
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But we can all agree that if I go from Dana 35/3.07 on 35’s to Dana 44/3.73 on 33’s I will be putting my son in a much better position correct?
 
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Jerry Bransford said:
Yep no way will its stock Dana 35 axle hold up for long with 35" tires, it will break an axle shaft. If you want to keep the 35" tires you'll either need to upgrade it with a Super 35 kit or replace it with a Dana 44. 35's are just too big for a stock Dana 35. Or reduce the tire size to nothing larger than 33". Do you know if there's a locker in either axle?
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:eeek: At my TJ I also have the 35 dana. with full floater , K&S (Schwarz from Germany) vacuum locker and 4:10 gear. Transmission 5 speed.
I drove 35 Inch for about 1 year. Now actual 33 Inch BFG K2. Now I think about going back to 35 Inch. Question: Is my 35 Dana with this modificatins strong enough to drive 35 Inch longer? :nusenuse:
 
JEEPdriver said:
:eeek: At my TJ I also have the 35 dana. with full floater , K&S (Schwarz from Germany) vacuum locker and 4:10 gear. Transmission 5 speed.
I drove 35 Inch for about 1 year. Now actual 33 Inch BFG K2. Now I think about going back to 35 Inch. Question: Is my 35 Dana with this modificatins strong enough to drive 35 Inch longer? :nusenuse:
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All I can tell you is what I know about the ‘05 X with 80K miles I just bought my son. PO had a 6” lift, Dana 35/3.07 rear, running 35’s. For how long I have no idea. Obviously a different situation than your’s considering gearing and all, but I got on it pretty good the day after I bought it and the axle broke.
 
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