Failure of a locker when an axle shaft dumps

snobrder · Jan 10, 2007

From what I understand the reason a Detroit may break when the shaft breaks is the pressure on the side plate teeth is still there, but since the outter plate now doesn't have anything to put pressure on, the plates start to unload. When they unload so far, there may not be enough engagement of the teeth so the teeth shear off. Kinda the same reason behind having good backlash on a ring and pinion. Too much backlash and you risk breaking the teeth of the ring under a load.

I ran into this when the Lock-Right in my old 44 gave up. The cross pin snapped causing the plates to unload. Since they were still under a load, they stripped the top 1/8" off the teeth because the load was more than the small section of teeth could handle.

I'd guess the reason it only breaks sometime is because sometimes you break a shaft under a shock load instead of a steady pressure. Like bouncing the front and coming down hard breakage as opposed to having a tire trapped under a rock and gasing it type breakage.

Agrover · Jan 10, 2007

420willys said:
couple questions, does a detriot in a 9'' thats been resplined to 35 spline 1.5 axles have a tendencey to break faster then a stock 31 spline when under axle breaking shaft loads. the other question, are full case detriot's breaking more than the two pieace carriers, like the ones found in 14 bolts or rockwells.

edit i see that alot of 60's are breaking along with the two pieace carriers, jason.

A friend of mine has an early (35 year old) 9 inch Detroit in his LandRover that has broken around 25 axles and 1 ring and pinion over the years without any failuresto the Detroit itself. The difference between this and later detroits is that all gears were cut from steel forgings, not investment cast like later stuff. Also the side gears had full length dog teeth without the annular groove that the later so called silent type ones have to retain the hold out rings. According to my 10 year old Trac Tec manual the earlier design is still available for heavy duty applications on log skidders, wheeled dozers etc, which suggests that the manfacturers recognise the limitations of the later designs.
Bill.

ramv · Jan 10, 2007

Broken 3 70 shafts no Detroit failures.
Broke 1 9.25" shaft, my Powertrax locker surivived
Broke ~ 10 Dana 44 shafts/joints, ARB laughs them off
Broke 1 Dana 60 shaft, ARB again un affected.

Not sure if I have been lucky on the auto locker breaks, but it does make you feel good know the arb is the least of your worries when the wheels are cranked, you hit the juice and hear the snap....

Go2Guy · Jan 10, 2007

Thump said:
On the note of larger detroits versus the smaller ones... the loads applied to the driver gears is proportionally the same as those experienced during a smaller-sized sibling's shaft failure. Just because the parts are bigger, doesn't mean that it takes the same force to break an axle. If so, we'd all be running Dana 27's and converting for open knuckles :laughing:

Actually- it is relative. say a 9", 60, 70 and 14 bolt all run a 1.5" shaft- that's a constant- now- which of those Detroits has larger drivers? the larger diameter the driver the more mechanical advantage it has compared to the axle diameter- also more teeth- almost like having a bigger ring gear etc- think about it. I can tell you the 60 drivers are quite a bit larger than the 9" drivers. But a HP 60 does not live well in the rear of a comp buggy.

The little teeth you see in a detroit should not scare you- think of it this way- if the avg diameter of the driver was 2.5" (2.25 ID and 2.75" OD) would "little splines" bother you on a 2.5" axle shaft??? I did not think so

.

Nonetheless- they can break from extreme recoil- the sad part is- the guys who have the most problems are the the peeps who wont pony for the better axles and u-joints out there or insist on running 49's with a big block in a 5000lb rig. Shit breaks- what can I tell you?

The Detroits have some good advantages in the right applications- like any other locker/spool. The 9" is special in that there is not much room in there for bigger locker pieces. The ARB for the 9" had/has lots of issues for similar reasons.

Go2Guy · Jan 10, 2007

420willys said:
couple questions, does a detriot in a 9'' thats been resplined to 35 spline 1.5 axles have a tendencey to break faster then a stock 31 spline when under axle breaking shaft loads. the other question, are full case detriot's breaking more than the two pieace carriers, like the ones found in 14 bolts or rockwells.

edit i see that alot of 60's are breaking along with the two pieace carriers, jason.

Decent question- on one side, the drivers are the same diameter where the teeth are doing the work.

All else being equal, the 31 spline will fail first and shock your teeth on the drivers- will it be enough to hurt the teeth? possibly, but it will take more load to break the 35 spline axle- so the teeth may be happy becasue you did not break the axle- but when the axle does break- more recoil becasue more stored energy has been released- make sense?

Obviously, I'm confident in the risk management for our team- axle breakage is unlikely and my detroit has lived 3/4 of the time- it's interestintg to note that it failed when the spicer joint let go, but not when the stubs let go- the flailing of the remaining stub/unjoint likely absorbed a lot of the energy before the Detroit saw it.

Any good drivetrain shop should be able to sell you these parts- I got mine "direct" Randy's would be my first call otherwise.

Tech Tim · Jan 10, 2007

In talking with a Detroit tech/engineer many years ago (maybe 98 or 99?), he said the reason they break when a shaft or hub lets go is that whichever side lets go is now in a freewheel state, but only for a fraction of a second and then it tries to lock up again. Basically: loaded, unload, slam back into load and bang.

And iirc, he said something about older forgings vs investment casting Detroits also. Don't remember exactly, too much fog between now and then...

LASER · Jan 10, 2007

Hey Detroit Locker
I spend a lot of money on your stuff, fix this problem please:flipoff2:

TRD · Jan 10, 2007

I have seen 2 detroit lockers fail at the same time as a warn fron hub (in D44)

I one case Detroit refused to fix the locker and was unwilling to send replacement parts. It was replaced by a lock-rite.

In the other case replacement parts were obtained and the locker was fixed.

I will never buy a detroit locker. Both breaks (except the locker) were easy to fix. But because of the broken locker they couldnt wheel any more. Complete BS. ARB's, Lockrite's and others dont seem to have a problem.

Why doesnt detroit fix this???????

Trailduster79 · Jan 10, 2007

I killed a front 35 spline Dana 60 detroit when I broke a rear axle shaft.

Was on a pretty nasty washed out hillclimb with my drivers side rear wedeged down in the bottom of the wash.

That shaft went, and took out the passengerside half of the detroit and the driver's side front locking hub.

Have since broken one stub, and one hub up front with no problems with the detroit.

Have also broken 2-3 other rear shafts with no problems with the detroit in the front.

420willys · Jan 10, 2007

Tech Tim said:
In talking with a Detroit tech/engineer many years ago (maybe 98 or 99?), he said the reason they break when a shaft or hub lets go is that whichever side lets go is now in a freewheel state, but only for a fraction of a second and then it tries to lock up again. Basically: loaded, unload, slam back into load and bang.

And iirc, he said something about older forgings vs investment casting Detroits also. Don't remember exactly, too much fog between now and then...

i understand the sudden load and un-load, but does a lockright break shafts under these condition's. i have bolth ( a LR in my 60 and a DT in the 14 bolt ) and i am a little concerned about the rear. is the racthcing efect on the lockright help stop the sudden shock load the other shafts see's buy opening up and allowing the teeth to stay aprt, jason.

Tech Tim · Jan 10, 2007

420willys said:
...snip... is the ratcheting efect on the lockright help stop the sudden shock load the other shafts see's buy opening up and allowing the teeth to stay aprt, jason.

That would probably be a good synopsis.

rcurrier44 · Jan 10, 2007

420willys said:
i understand the sudden load and un-load, but does a lockright break shafts under these condition's. i have bolth ( a LR in my 60 and a DT in the 14 bolt ) and i am a little concerned about the rear. is the racthcing efect on the lockright help stop the sudden shock load the other shafts see's buy opening up and allowing the teeth to stay aprt, jason.

Lock rights tend to shear the pins...I have seen alot more lockright failures than detroit failures. From what I have seen the lockrights fail easier but they are less expensive to replace or repair.......

WheelingPiazza · Jan 10, 2007

Just an FYI for those of you running a D44.

The side gears from a 3.73 and higher(I think thats the ratio split) will work with a 4.11 and lower detroit. Side gears can be had by a few vendors here and of course randys. Most people are under the impression that the side gears are expensive. At one point it was more money to buy a side gear then a new locker. The last time I priced side gears for a 44 detroit they were in the 150 range, I ended up finding a 3.73 detroit for 200, Which gave me both sidegears, springes etc.

When my side gear finally let go, I had broken 2 outters and 1 inner. All Yukon shafts with CTMS.

I think the real question is why does a 4340 shaft go before a hub goes.

I am upgrading to a 60 at the moment and will go detroit. 14 bolt has a spool that I will upgrade to a detroit eventually.

Tim Florian · Jan 10, 2007

Go2Guy said:
The ARB for the 9" had/has lots of issues for similar reasons.

Can you go a little deeper with this for me?

I'm torn between buying another Detroit and switching to an ARB. I run 35 spline 300 m shafts at all 4 corners, so I shouldn't be breaking them, but when I do I'd like to be able to change the shaft and get back by the time on due for my next course.

I was thinking that the ARB would handle the load because they always did in my toy axles. Every time I've ever broke an axle it has broke the Detroit.

So due you know guys that have broken there ARB's in a 9" 35 spline application. Due to axleshaft failure???

Tech Tim · Jan 10, 2007

Tim Florian said:
Can you go a little deeper with this for me?

I'm torn between buying another Detroit and switching to an ARB. I run 35 spline 300 m shafts at all 4 corners, so I shouldn't be breaking them, but when I do I'd like to be able to change the shaft and get back by the time on due for my next course.

I was thinking that the ARB would handle the load because they always did in my toy axles. Every time I've ever broke an axle it has broke the Detroit.

So due you know guys that have broken there ARB's in a 9" 35 spline application. Due to axleshaft failure???

ARBs very rarely break from a broken axle shaft. What you would see if anything is a broken cross shaft from the broken end of the axle slamming into it or the air side bearing journal splitting from the broken bits of the shaft wedging it apart. Over the years ARB engineering has made a few changes to help limit breaking into air passages in the bearing journal, but when things start splitting apart, it's hard to control where the damage will happen.

There have been some locking gear failures in the 35 spline 9", but up until I left ARB in Sept. there were no RD99 failures due to a broken shaft.

J Kimmel · Jan 10, 2007

I broke several birfields and one R&P in a Toyota 8", and a couple of hubs too without a locker failure. I broke one inner shaft and the Detroit I had went with it. When I took it apart the gear teeth inside the Detroit were rattling all around.

thump93yj · Jan 10, 2007

I run Superwinch hubs... on a scout 44 front with alloy shafts, spicer ujoints, 38.5x14.50 swampers. The hubs are usually my fuse and I've been through maybe half a dozen of them over the years... I've never broken the axle shafts. The last hub break finally took out my detroit. It broke all but 4 of the teeth on one side and ALL of the teeth on the other. It was a hard shock type break as it completely broke the hub lock (the cast portion) in half.

I'm happy with detroit given the longevity I've experienced with their stuff... but I do think those teeth could be just a bit beefier.

tsm1mt · Jan 10, 2007

420willys said:
i understand the sudden load and un-load, but does a lockright break shafts under these condition's. i have bolth ( a LR in my 60 and a DT in the 14 bolt ) and i am a little concerned about the rear. is the racthcing efect on the lockright help stop the sudden shock load the other shafts see's buy opening up and allowing the teeth to stay aprt, jason.

I wiped out my Lockright in my 44 front when I broke a hub and broke a U-joint at the same time.

It broke the shear pins in the LR and cracked the drivers, and it stopped unlocking when making left turns.

Go2Guy · Jan 10, 2007

Tim F- TechTim knows best on the ARB's for the 9, I PM him when I have questions. That said, there have been issues for 9" 35 spline ARB's with o-rings. I've seen way more thirds with ARB's getting changed/tweaked/fail at comps than detroits- ask around, talk to twisted etc.

More food- when I break an axle (especially the inner) I know I might have compromised the Detroit and can plan for that while wrenching in the pits. If I don't break an axle- I know the Detroit is with me til death. With the ARB the o-ring issues strike at random giving you an open dif. Trail guys may look at it differently than comp guys- I dunno- but obviously, I've made my choice

Tim Florian · Jan 10, 2007

Go2Guy said:
Tim F- TechTim knows best on the ARB's for the 9, I PM him when I have questions. That said, there have been issues for 9" 35 spline ARB's with o-rings. I've seen way more thirds with ARB's getting changed/tweaked/fail at comps than detroits- ask around, talk to twisted etc.

More food- when I break an axle (especially the inner) I know I might have compromised the Detroit and can plan for that while wrenching in the pits. If I don't break an axle- I know the Detroit is with me til death. With the ARB the o-ring issues strike at random giving you an open dif. Trail guys may look at it differently than comp guys- I dunno- but obviously, I've made my choice

Thanks!!!:smokin:

Failure of a locker when an axle shaft dumps

snobrder

Agrover

ramv

Go2Guy

Go2Guy

Tech Tim

LASER

TRD

Trailduster79

420willys

Tech Tim

rcurrier44

WheelingPiazza

Tim Florian

Tech Tim

J Kimmel

thump93yj

tsm1mt

Go2Guy

Tim Florian

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