7.5 28-spline locker reliability opinions wanted

[Just_Randy]

Question:

In your experience (reading online or in real life), if I locked this axle, how likely would it be that I would twist an axle?

I don't think running a locker while pulling trailers really counts as testimony. What I need to know is if only one wheel is touching the ground, can the axle diameter withstand the torque?

If not, is there anyway I can put 31 spline axles in? What is the approx cost?

Or should I replace the whole axle with an 8.8 with the 31 splines? What's the cost of that?

A story:

My friend has a jeep with a d35 in back. The spider gears explode. So he parks that and drives his ranger with the 7.5. Not long after, the cross pin falls out and gets ground to bits by the ring gear. Here he is with 2 vehicles with bad diffs in the same month.

So I put a new 3/4 inch shaft in for the cross pin for him, but the ring and pinion are damaged and it makes a noise on the coast side. On the jeep, the cross pin holes are wallowed-out, so I drill the .685 hole to .75 and use the 3/4 pin. I weld everything solid. 3 days later, he twists an axle in half just driving normally around town. Never even took it wheeling.

So I'm reading online and discover the d35 is a major piece of junk. See here http://www.billhughes.com/dana35c/

I find the d35 has axles of 1.16" diameter. The 7.5 has axles of 1.2" diameter. So now I'm worried that the extra .04" isn't enough.

Honestly, I think the 7.5 inch ring gear is fine. The 3/4 cross pin is fine too. My only concern is the 28 spline axles.

Btw, all vehicles mentioned here have 31 inch tires.

Thanks

 

[martin]

Sounds to me like someone has a bad case of lead foot. You can break anything if you try hard enough.

 

[Just_Randy]

He drives slower than the average grandma actually.

 

[adsm08]

My issue with the question as stated is that you say he "twisted the axle in half".

Well increasing the spline count won't help that. If it didn't strip off the splines increasing the spline count won't help anything. It will actually make it worse because it gives the splines more gripping surface in the area most prone to failure. That means more power can be handled by the normally weak area. If he broke farther out you will only make that issue worse.

If you are needing something that can be driven on the street but will not get you stuck off road, for the way it sounds like he drives I think a limited slip might be your only option.

If sounds to me like he will probably break any rear 28 or 31 spline, 7.5 or 8.8, if you just put a locker in. If you go with an auto locker he will probably blow that up too. A selectable locker like an ARB would probably work well, but those are big money.

Limited slip should be fairly reliable on the street and will still allow a high degree of power transfer if one wheel doesn't have traction off road. It is not as good as a locker, but it is better than blowing up axles every few weeks.

My personal preference would be a Torsen unit. About as close as you can get to a locker without a locker.

 

[adsm08]

He drives slower than the average grandma actually.

It's all about the corners. You weld up the spiders and you can go as fast as you want in a straight line. You put any throttle to it in the corners and you start breaking stuff.

 

[Just_Randy]

More splines = bigger axle shaft. 28 splines is 1.2" while 31 splines is 1.32". The axle he broke was 27 spline, which is 1.16"

I'm really not worried about him. He can do what he wants. I'm worried about me and my 7.5 with 28 splines

 

[Just_Randy]

Ideally I would want an ox locker, but my issue is the 1.2" 28-spline axles. I'm pretty sure they won't hold up when locked unless I'm really careful.

 

[4x4junkie]

Axles don't just twist in half...

What size tires is he running?

 

[4x4junkie]

Axles don't just twist in half driving like an average grandma...

What size tires is he running?

 

[Just_Randy]

snip

Btw, all vehicles mentioned here have 31 inch tires.

Thanks

Yup, axles do just twist apart. This guy collected over 100 examples of just that. http://www.billhughes.com/dana35c/ and its not even a 4x4 or jeep site. No clue how he attracted that much attention to collect all those pics.

More examples of how easy it is here:

http://www.youtube.com/watch?v=WSaBWo5qVaw

http://www.youtube.com/watch?v=nRHwjCYMlbM

http://www.youtube.com/watch?v=GuMnuT7sdnI

But...

Driving like a grandma with an open diff he managed to lose the cross pin in both axles, which resulted in spider gear damage in the D35 and ring gear damage in the 7.5.

Then I welded the D35 solid and he twisted an axle just backing up to turn around... much like grandma would. The axle shaft had probably been fatiguing for the 3 days.

Anyway, all that is beside the point. The D35 is a notorious hunk of junk with the 27 spline 1.16" axles as evidenced by the aforementioned pics and videos. My concern is the 7.5's 1.2" axles. How can .04" be that much stronger?

 

[Scrambler82]

If you are spending the money for an OX Locker get an explorer axle.

 

[PlumCrazy]

I have seen 7.5s welded on pavement at the strip behind a small block with no issues pass after pass.

Sent from my DROID RAZR using Tapatalk 2

 

[Just_Randy]

If you are spending the money for an OX Locker get an explorer axle.

Makes sense

I have seen 7.5s welded on pavement at the strip behind a small block with no issues pass after pass.

Thanks!

That's what I'm wanting... opinions and what you've seen.

 

[4x4junkie]

Yup, axles do just twist apart. This guy collected over 100 examples of just that. http://www.billhughes.com/dana35c/ and its not even a 4x4 or jeep site. No clue how he attracted that much attention to collect all those pics.

More examples of how easy it is here:

http://www.youtube.com/watch?v=WSaBWo5qVaw

http://www.youtube.com/watch?v=nRHwjCYMlbM

http://www.youtube.com/watch?v=GuMnuT7sdnI

But...

Driving like a grandma with an open diff he managed to lose the cross pin in both axles, which resulted in spider gear damage in the D35 and ring gear damage in the 7.5.

Then I welded the D35 solid and he twisted an axle just backing up to turn around... much like grandma would. The axle shaft had probably been fatiguing for the 3 days.

Anyway, all that is beside the point. The D35 is a notorious hunk of junk with the 27 spline 1.16" axles as evidenced by the aforementioned pics and videos. My concern is the 7.5's 1.2" axles. How can .04" be that much stronger?

Your "grandma" is not very average if she drives like any of those examples...


But yeah, the 28 spline Ford stuff is fairly decent.
Ford shafts have a different spline pressure angle that isn't cut as deeply into the shaft as on Dana shafts. This makes the 28 spline Ford shaft about on par with a 30-spline Dana shaft.

 

[bobbywalter]

Yup, axles do just twist apart. This guy collected over 100 examples of just that. http://www.billhughes.com/dana35c/ and its not even a 4x4 or jeep site. No clue how he attracted that much attention to collect all those pics.

More examples of how easy it is here:

http://www.youtube.com/watch?v=WSaBWo5qVaw

http://www.youtube.com/watch?v=nRHwjCYMlbM

http://www.youtube.com/watch?v=GuMnuT7sdnI

But...

Driving like a grandma with an open diff he managed to lose the cross pin in both axles, which resulted in spider gear damage in the D35 and ring gear damage in the 7.5.

Then I welded the D35 solid and he twisted an axle just backing up to turn around... much like grandma would. The axle shaft had probably been fatiguing for the 3 days.

Anyway, all that is beside the point. The D35 is a notorious hunk of junk with the 27 spline 1.16" axles as evidenced by the aforementioned pics and videos. My concern is the 7.5's 1.2" axles. How can .04" be that much stronger?

I have seen 7.5s welded on pavement at the strip behind a small block with no issues pass after pass.

Sent from my DROID RAZR using Tapatalk 2

welded in a light linked car a 7.5 can get lucky, long time. i too have seen it in light fox cars.



i hate the 7.5. in a leaf spring application and my chassis with a load, i can bust a 7.5 in front of you right directly after i bolt it in my truck with a mere 260 rwhp. i have not lost that bet yet.

arb.....in a 31 spline 8.8......hate that fawker too. but i way overloaded that past intentions as well.



i cant believe how long some shafts last over others when spooled on the street. the 28 splines usually pencil/fail in short order if run with stout springs or traction bars if there is a load on them.


if you want to tow, get a disc brake explorer axle as the most cost effective upgrade....especially spooled.