Basic differential questions

[UKTJ]

I didn't want to hijack a recent thread on differentials, but a couple questions occured to me when I read it, so I thought I'd put them in a standalone thread.

I read comments on the relative weakness of a Dana 35 rear differential versus a Dana 44. What I now wonder is what is it that is the weakness in the Dana 35? I see a Super 35 kit recommended, but when I seached for that online what I found was an axle upgrade that said a new carrier would be required for the 30 spline axles. So is the weakness the fact that the Dana 35 only accomodates a 27 spline axle and it is that that is the weakness, rather than anything internal to the differential itself?

My second question relates to front versus rear. A Dana 35 in the rear is considered a potential weakness, but a Dana 30 in the front seems to be less of a concern. But the Dana 30 also has the 27 spline axle set up I believe. Why is the rear more of a concern and what merit is there to upgrading the front axle to 30 spline axles?

Novice questions I know, but if I don't ask I'll remain this uneducated.

 

[thekidwithquestions]

they came with c-clips that held the axle shaft in place, that's the weakness I know about. I was very surprised about how easy the axle shafts were to take out when I swapped my axle so im sure in would not be hard for one to come loose on the trail

 

[jjvw]

they came with c-clips that held the axle shaft in place, that's the weakness I know about. I was very surprised about how easy the axle shafts were to take out when I swapped my axle so im sure in would not be hard for one to come loose on the trail

The c-clip isn't the weak part. When the 27 spline axle breaks, the c-clips still need to be removed to get the remaining axle stub out.

 

[imahnu]

The C-Clip design isn't the big issue when it comes to the Dana 35's weakness. It's the OE shafts that are a problem with 35" tires. Those shafts are resolved with a Super35 kit that are stronger than OE Dana 44 shafts.

The reason a Dana 30 with 27 spline shafts holds up better is because the front axle is put under less load and stress relative to the rear axle which is why its common to have a bigger rear axle vs front axle.

A Dana 44 rear has a larger R&P than a Dana 35 as well which also makes it somewhat stronger.

A Dana 30 with 30 spine axles isn't particularly any stronger than 27 splines because the outer stub axles still use 27 splines. They can be replaced with 30 spline outers and hubs but that comes at an increased cost for little value. 27 spline chromoly axle shafts are good up to 35" tires. 30 splines doesnt let you jump up to 37" tires so IMO their isn't a big value added by the increase. Hope this helps!