9" rear exploded

[chuzie]

My 9" exploded the other day on an obstacle. I wasn't beating on it terribly, so guessing an impending failure decided to go nuclear.
Anyway, I'm trying to decide my path forward and looking for educated input.

75 housing
Explorer discs
Duff's 4-link
4.56
Grizzly locker 31 spline

The rear cover of the housing has been leaking for some time from tiny cracks that may have been rooted in the Duff's 4-link crossmember. I had no leaking on the front and the bolts were all tight (had just checked the week before). I'm guessing I smacked the yoke armor pretty hard at one point at weakened the support; just a guess.

Starting over with another housing means attempting to transplant the 4-link crossmember (nightmare) or attempting to redo 4-link from scratch and possibly losing my Explorer brakes due to the unique bearing size.

Considering:
Pull, strip, clean, blast
Wet magnaflux and straight check
Nodular 3rd
New gears
Shave + brace bottom.

The alternatives seem more expensive to me with little upside, but that's why I'm asking the collective.

Thoughts?

 

[ntsqd]

Time for a Dana 60 or 14bff.

Not at all easy to use the Explorer RDB's with a FF wheel hub because spinning parts want to be in the same place as stationary parts, BUT you can use an early 2000's Expedition RDB's, which are a slightly larger version of the Explorer brakes, and those will fit a D60 for sure. Not all that long ago you could buy all of the parts needed for the Expi brakes off Rock Auto for just at $500. Except for the brake hose banjo bolt. They had no listing for those.

 

[Broncobowsher]

I would say any of the basic aftermarket carrier will be good. Don't need a high end version. Don't need to trash everything and start over with a ton of new custom work.
Not a big fan of the stock small banjo housing, but with the 4-link brace I feel it is beefed enough.

 

[jamesroney]

Take a breath...look at what you did. Investigate, determine root cause, learn from it, and don't do it again.

The failure I see is clearly the ejection of the pinion from the carrier housing. That looks like a stock C7AW-E housing, and your failure is similar, (but not the same) as the typical pinion ejection. The vast majority of users employ the C4AW-B or D0OW-B "nodular" housing to gain strength and reduce deflection.

But your housing did not fail EXACTLY like most of them do. I can see the tensile fracture in the housing, and the pinion support appears intact. The rear pocket bearing is the give-away. The pocket failed in the area nearest the ring gear. That cannot happen from a pure ring gear / pinion interaction. Something forced the pinion out sideways. Did you say you have a pinion saver, or skid? If so, I sure hope it isn't mounted to your pinion support bolts. (there's only 5 x 3/8) If you have a pinion guard, THAT's what broke your 9 inch. Cast iron is remarkably strong in compression, and catastrophically weak in tension.

I'm going to say that ANY high performance improvements (Like N-case, Daytona support, thru bolts, HD case) are not going to help you. Maybe a 10 bolt pinion support. But you really need to mount that pinion skid different. Then any old normal 9 inch chunk will work just fine.

Obviously, I run a 60. But that's just me...

 

[snipes243]

The more I think about it I believe you had a fatigue crack on the third member either on the pinion support needing surface or in the case itself. If it was the pinion guard I would expect to see some elongation on the bolts, but they looked normal. Overall it’s an almost 50 year old case, that has been beat to deaths by the guy behind of the wheel

As for the rebuild a Dana 60 would get you a little more strength but would come with other issues. You’re not running a lot of horse power or gearing. I saw just put another third member in it and get back on the trail.

 

[Broncobowsher]

I'm curious how tore up the pinion support snout is on the front of the pinion gear. If that failed, the forces on the pinion would be like a pinion skid pushing up. And explain the sideways blowout, and the peel going up the case.

 

[snipes243]

I'm curious how tore up the pinion support snout is on the front of the pinion gear. If that failed, the forces on the pinion would be like a pinion skid pushing up. And explain the sideways blowout, and the peel going up the case.

It was intact. Its crazy cause when it popped it sounded like a fail ujoint not the diff grenading

 

[nvrstuk]

Chuzie.... hate to say it but it was inevitable... I have several pics of catastrophic 9" failures just putting stress on them, like going up a steep dirt incline without hopping or stress loads or .... list goes on. They were NEVER designed for the torque load we put them thru.

I finally gave up after twisting 35 spline ARB's in half, 9" cast iron failures like you had, etc. Did what I should have done in the '90s when I started building super strong 9" rear ends that kept failing... I built a shaved 14 bolt and have never looked back. Shake my head because of the missed trips, money spent and time wasted on rebuilding a stronger 9" EACH AND EVERY time just to have it last a couple years and then fail. Only one of my 9" failures was my fault from driving. Got to admit that shifting into 2nd at 6,100 rpm with 37"s slightly deflated on pavement with one of my earlier stroker engines might have been the cause but... all the rest of the destruction was normal wheeling w/o wheel hop stress loading.

Benefits:

-Shaved 14 bolt is 1/4" less clearance than a fabricated 9" housing and mulitple times stronger
-You will NEVER experience a wheel brg failure and have an axle break dropping your rear end to the ground at speed.
-It weighs appr 25lbs more than a fabricated 9" ( I have weights posted on my build) and much stronger
-It is much stronger than a D60, better pinion angle and shorter pinion for a longer driveshaft than a Dr60
- MUCH cheaper than buiding a "super strong" 9" rear.


Just my experiences backed by guys here who were trying to convince me to go 14 bolt 20 yrs ago and I wanted to stay with a 9" because they are #1 astrong, #2 lightweight, #3 dependable.... oh yeah, non of those 3 things...

 

[Shimmy]

aren't you the guy that's also gone thru 5 track bars? "pounding the rocks" if i remember? i'd see this as an opportunity to beef up to a stronger axle 60 14bolt and pound on.

 

[chuzie]

aren't you the guy that's also gone thru 5 track bars? "pounding the rocks" if i remember? i'd see this as an opportunity to beef up to a stronger axle 60 14bolt and pound on.

Actually I think the count is 4

 

[chuzie]

Thanks for all the input y'all. Hopefully I'll find the motivation to go out to the shop in the next few weeks and yank the sucker out.

 

[Apogee]

No to jack this thread, but if the SD super-60's are the bomb up front, and the GM 14-bolts are the bomb out back, what do you do about the mismatched 8x170 and 8x6.5 wheel patterns?

 

[ntsqd]

No to jack this thread, but if the SD super-60's are the bomb up front, and the GM 14-bolts are the bomb out back, what do you do about the mismatched 8x170 and 8x6.5 wheel patterns?

https://barnes4wd.com/products/05-up-super-duty-dana-60-8x6-5-drill-jig is one option

Buy them already done: https://branikmotorsports.com/timken-05-up-super-duty-unit-bearings-8-on-6-5/

 

[Apogee]

https://barnes4wd.com/products/05-up-super-duty-dana-60-8x6-5-drill-jig is one option

Buy them already done: https://branikmotorsports.com/timken-05-up-super-duty-unit-bearings-8-on-6-5/

Thanks and cool beans...though it seems like somebody could make an 8x170 hub for the 14-bolt (and maybe they already do), since that's the conventional hub and won't need replacement any time soon (versus normal maintenance) like the front unit-bearings do.

 

[ntsqd]

I've personal bias against the 8x170. They should have left it alone, I see no good reason for the change.

That said, I looked a little to see if there was such a hub and did not find it.