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View Full Version : If a D35 is weak then why not lock it?


boomhauer
January 15th, 2006, 19:16
I have an 8.25 and just installed a no-slip. Powertrax states that the locker actually "strengthens" your rear diff, which getting rid of all that side and spider gear crap will surely do and to which i concur.

So question:
If a locker improves the strength then logically people "should" lock their D35's to enable the rear to handle the action and tire sizes (nothing crazy though) without spending cash on changing the rear.
Just curious about this as i see alot of "it's not worth it to lock the D35" threads.
Makes sense for a DD/Weekend Warrior, no?

Lincoln
January 15th, 2006, 19:18
Because it increases the stress on the axles which are junk.

boomhauer
January 15th, 2006, 19:34
Because it increases the stress on the axles which are junk.

... it reduces the stress, specifically driveline windup and abrupt stoppage incurred in open and limited-slip diffs. -Powertrax.

5-90
January 15th, 2006, 19:36
While a locker might remove the "weak spot" found in the spider gears and side gears, they won't do anything about the splines of the shafts - which is actually the weak point.

Now, if you could start by increasing the size of the axle halfshafts, you'd be doing something useful.

However, if you're going to increase the strength in the centre of the axle, you'd not be changing the strength of anything else, but making the halfshafts relatively weaker - which increases the potential of snapping shafts. D35 shafts are damn close to toothpicks, which is why you want to think about changing the axle assembly if you're worried about strength - nearly anything will be better (start by looking for larger axle shafts, taken from the smallest diameter, which is the weakest point. If you can tear it to bits before you take it, inspect the axle shafts for any striations, scratches, or gouges - that's like a line saying "tear here" - a point where stresses concentrate.)

5-90

Jeffro600
January 15th, 2006, 19:38
The problem with the D35 does not lie in the spyder gears...its the toothpicks it uses for axle shafts.

sidriptide
January 15th, 2006, 19:49
there is no real "fix" for its inherent weakneses but you cannot deny the fact that eliminating wheel spin DOES reduce the potential for breaking a shaft. it wont prevent it. but it will eliminate that specific "weakness".

Wiley Coyote
January 16th, 2006, 00:00
there is no real "fix" for its inherent weakneses but you cannot deny the fact that eliminating wheel spin DOES reduce the potential for breaking a shaft. it wont prevent it. but it will eliminate that specific "weakness".

Actually, that’s quite the opposite. If you are running an open carrier and one tire hits something solid, the other tire will spin, burning off all of that excess torque. If you are running a locker and one tire hits something solid, both tires are going to try to turn and some thing has to give. Normally the weakest point, which would be one or the other axle shaft.

Captain Ron
January 16th, 2006, 00:13
Because it increases the stress on the axles which are junk.

I guess I'll believe that the day I'm following you around...

on 37's

... you that is. :D

--ron

afd516
January 16th, 2006, 00:18
Actually, that’s quite the opposite. If you are running an open carrier and one tire hits something solid, the other tire will spin, burning off all of that excess torque. If you are running a locker and one tire hits something solid, both tires are going to try to turn and some thing has to give. Normally the weakest point, which would be one or the other axle shaft.


This, in theory would be true. Except, the spinning shaft would break before the open diff transfers the torque from one shaft to the other. In other words,the spinning, tooth pic, dana 35 axles shafts break before the diff could do its job. Weak dana 35's. Stonger, larger axles shafts are less likely to break as the open diff does its job.

With any axle, when you add a locker it lessens the likely hood of wheel spin but does not change the strength of an axle shaft. After the locker has been added and traction has been lost, then gained abruptly, the wheel that gained the sudden traction is probably the shaft that is going to break. Or, the wheel that has so much traction it wont spin, snap, there goes a shaft.

GSequoia
January 16th, 2006, 00:23
No, of course it doesn't literally weaken the shaft.
The thing is that an open diff will allow the slip of a non traction wheel moving where as a locked diff will not. Think about it.. How often (for those that are still running 35's...) are you in a situation where BOTH wheels are up against hard traction but you cannot move?

Think of it like this.. You have this force appied to a shaft that is trying to twist but somethig at one end (big rock, etc) won't let it. If you have an open diff then the other side, which either isn't bound at all or is bound to a smaller degree will spin at that point, taking most of the torque/power out of that completely bound up wheel.

Now put a locker into the equation. You have both shafts FORCED to turn at an equal rate, the same power is applied to both shafts. The one that doesn't have much bind will freely spin as it did before. The one that is bound up will be FORCED to spin, if the amount of torque necessary to overcome bind exceeds the amount of torque the shaft is capable of handling the shaft will break.

There is no merit to lockers making axles stronger. Spiders don't break often.

Wiley Coyote
January 16th, 2006, 00:35
No, of course it doesn't literally weaken the shaft.
...There is no merit to lockers making axles stronger. Spiders don't break often.

Right on! All a locker does is make other weak points become more obvious. Besides the axle shafts, the next weak point in a Dana 35 is the carrier itself (unless you replace it, like with a Detroit), then the axle tube. With that said, I’m running a Dana 35 with a Lock Rite and fully expect to shrapnel it at some point. I guess that would be a good time for me to upgrade to Dana 44s. :laugh3:

MudDawg
January 16th, 2006, 02:42
Formula for a bulletproof '35....completely gutted truck...nothing inside but seats...no winch...no zillion pounds of bumpers or armor...2.5 power...auto trans....and run 'er in mud only..no rocks...no pavement..no slamming into gear at 6k...no jumps...knowing when to give up and hook up a strap...oh...I did have my axles cryo'd since a buddy has a cryo business and did it for free.

I actually got to watch a UROC competition on TV this weekend...now I know why you need unobtainium everything to survive on rocks.

I have seen several rigs snap (D35) axles....they all did it at the dump of the clutch. maybe i'm just lucky. My MJ is getting a well built 8.8.

Roxtar
January 16th, 2006, 06:23
... it reduces the stress, specifically driveline windup and abrupt stoppage incurred in open and limited-slip diffs. -Powertrax.Gotta love Powertrax-bringing the funnay. :puke:

boomhauer
January 16th, 2006, 10:22
Actually, that’s quite the opposite. If you are running an open carrier and one tire hits something solid, the other tire will spin, burning off all of that excess torque. If you are running a locker and one tire hits something solid, both tires are going to try to turn and some thing has to give. Normally the weakest point, which would be one or the other axle shaft.

Actually according to Powertrax, you've got it the opposite...

"Wheel spin-up and abrupt stoppage can cause severe driveline trauma. This occurs easiliy with "open" and "limited-slip" differentials that rush power to a wheel that is slipping or becomes suspended in mid air, even momentarily. When abrubtly stopped by the wheel re-connecting with a high traction surface, the driveline attemps to absorb the extreme shock. Damage to driveline components can occur. Axle shafts may flex, bend or break...The Powertrax No-Slip Traction System gets rid of troublesome wheel spin-up and improves durability and reliability." -Powertrax

Sounds to me like it would increase the chances of NOT breaking the toothpick axles. Ah, but what does Powertrax know.

Lincoln
January 16th, 2006, 10:37
Can't believe I'm contributing to a discussion about a D35. :puke:


You have to consider that when you lift a tire and decrease traction on it with an open it just spins. With a locker it will have all the torque on the shaft with traction. There is where you will find the week spot.

The lunch box may improve the strenth of the spiders but it is also hard on the carrier which is not to great to begin with.

Then you have the issue of the R&P. I have seen a lot of those break. With both tires locked together it gives the ablility to transfer more torque to the ground. That torque has to go thought the R&P.

D35's were ok running open under a stock or close to stock rig. Lock them and/or put large tires on them and they will have problems. Bearings, gears, shafts, everywhere. That is why I try convince people to save their money on locking a D35 and swap in another axle. That $200 or whatever you have to pay for a lunchbox locker is a good step towards something better.

I don't really care for them but I see 8.8 exploder axles for the $350-$500 range all the time. From the factory I've seen 3.27's, 3.55's, 3.73's, and 4.10's. That covers pretty well everything except the stick guys. Money much better spent.

Lincoln
January 16th, 2006, 10:42
I guess I'll believe that the day I'm following you around...

on 37's

... you that is. :D

--ron

I've decided that 35 spline shafts are to much roatating mass. I have a 10 spline D44 with flanged axles in my shed that is dieing to be used. I also have a good tip on a closed knuckle D25 which I'm planning on using because the closed knuckles keep out the walmart grime. Detroit makes lockers for both and that will get me all the strength I need for those 37's.

Men don't need strong axles they just need a p*ssy foot. :D

XJ_ranger
January 16th, 2006, 10:50
come on man - everyone says its crap...

then it must be!

there is no other discussion to be had....

its crap!

Roxtar
January 16th, 2006, 11:47
Maybe you're right.
Work with me here people, if you have a D35 with both axles locked together, isn't that really the same as having an open D70?
Hell, what's stronger than a D70?

Can't believe I'm contributing to a discussion about a D35. :puke:I can't believe there are people here that actually believe the hilarious psuedo-engineering BS that Powertrax is trying to sell.
To suggest that a locker will lessen the stresses on an axle is just plain funny.
To actually believe them when they say it is just plain sad.

People, think.

Anything, ANYTHING, that aids traction will add stress to the axle components, period.

boomhauer
January 16th, 2006, 15:06
Anything, ANYTHING, that aids traction will add stress to the axle components, period.

Damn, the kitty litter just snapped my axle!

Rawbrown
January 16th, 2006, 15:55
Whats stronger than a Dana 70? how about a 40 spline gun drilled ford 9' or Dana 60... hasta
Maybe you're right.
Work with me here people, if you have a D35 with both axles locked together, isn't that really the same as having an open D70?
Hell, what's stronger than a D70?

I can't believe there are people here that actually believe the hilarious psuedo-engineering BS that Powertrax is trying to sell.
To suggest that a locker will lessen the stresses on an axle is just plain funny.
To actually believe them when they say it is just plain sad.

People, think.

Anything, ANYTHING, that aids traction will add stress to the axle components, period.

Wiley Coyote
January 16th, 2006, 22:21
I don't really care for them but I see 8.8 exploder axles for the $350-$500 range all the time. From the factory I've seen 3.27's, 3.55's, 3.73's, and 4.10's.


I’d be happy if I could find a Ford 8.8 for under $800 up here, you’d think those stupid things were made out of gold. A buddy bought a built 8.8 from Currie; $1800 delivered to his door. It was a lot of money, but a heck of a lot cheaper than buying a JY 8.8, rebuilding it, putting in gears and a Detroit. There are a lot of things I’m going to miss when I leave AK, but automobile parts prices isn’t one of them.

mattak
January 16th, 2006, 22:29
I’d be happy if I could find a Ford 8.8 for under $800 up here, you’d think those stupid things were made out of gold. A buddy bought a built 8.8 from Currie; $1800 delivered to his door. It was a lot of money, but a heck of a lot cheaper than buying a JY 8.8, rebuilding it, putting in gears and a Detroit. There are a lot of things I’m going to miss when I leave AK, but automobile parts prices isn’t one of them.

where are you getting these prices?? 800 bucks is steep considering in the last year there have ben a few for sale on alaska4x4network for 100 and 150

WB9YZU
January 16th, 2006, 23:07
A locker will not increase the strength of an axle unless the weak point is the differential.

:lecture: Think of it this way and it will apply to all axles.

Regardless of differential used, in a straight line optimum traction setup, each axle shaft gets the same amount of "load" which is 1/2 of the available torque.

Given a scenerio where one tire has traction and the other is in the air:

With an open axle, the tire with the most traction gets the least amount of power. That amount of power is dependant on how much traction is available to the other tire. If one wheel is in the air, the grounded tire will get zero torque. Tire slippage transfers power to the other wheel.

With an axle with a limited slip, the tire with the most traction will get a percentage of power greater than an open differential, yet less than 100% of the available torque. Tire slippage again transfers power to the other wheel.

With an axle with a locker or spool, the tire with the most traction gets a much larger % of the available torque. In a scenerio where one tire is airborne and the other is grounded, the grounded tire carries 100% of the availble torque. If that tire slips and regains traction, the amount of torque exerted on that axle is a factor larger than 100% of the available torque due to the moment of the tire/wheel.

Axle halves rairly break in the open or LSD scenerios, but often break in the Locker/Spool scenerio because that scenerion is where 100% or more of the available torque is exerted on the axle shaft.

Why lock a D35? Because it suits your needs at the time. Lots of folks with D35s, lockers and 31's out there who have had no problems and have enjoyed the comparative ease of which they now get around off-road.

Wiley Coyote
January 16th, 2006, 23:10
where are you getting these prices?? 800 bucks is steep considering in the last year there have ben a few for sale on alaska4x4network for 100 and 150

That price was from calling around to the local junkyards (North West, Hill Top, Durkalous (sp?), etc.). Price depended on exact vehicle/year/mileage/condition, but that’s the right ballpark. I was getting quotes of $400 for a pos Dana 35 with 4.10s. :scared: You can get the 8.8s out of Rangers for $400, but they have drum brakes. I think that the junkyards have caught on that people want the Explorer 8.8s because they have disc brakes. I already talked to Oddball about getting one and I’d rather not give up my first born. :rolleyes: Do the JY prices go down in the winter or are they always high? Who was selling an 8.8 for under $200?

Rawbrown
January 17th, 2006, 00:19
Very well put but damn did I go crosseyed reading it. so I will dumb it down a bit cuz I am in the mood.
is it the theory of relativity? Power takes the path of least resistance...
in an open diff that path is balance between both wheels. when one wheel spins it is evident that is the path of least resistance.
in a limited slip rear end, a small amount of resistance must be maintained on both sides of the diff to allow the clutch pack to tighten up and and limit the slip to the path of least resistance. a limited slip diff will only transfer a % of the power to the path of greater resistance.
a spool and a locker will transfer 100% of the power to both sides unlike an open or LS diff. a locker does not allow a wheel to travel slower than the carrier, only faster so it unlocks to do so.

a locked 35 is weak in 2 major ways that causes problems. the spider gears in an open and trackloc 35 have a tendancy to break a tooth.
the housing is on the flimsy side. not a big deal with an open diff. but can wear out clutch packs sooner.
Axle shafts need to be perfectly in line with a locker. a bent tube will force the shaft to misalign the locker leading to a broken locker.
Zuk, that was put very well.

A locker will not increase the strength of an axle unless the weak point is the differential.

:lecture: Think of it this way and it will apply to all axles.

Regardless of differential used, in a straight line optimum traction setup, each axle shaft gets the same amount of "load" which is 1/2 of the available torque.

Given a scenerio where one tire has traction and the other is in the air:

With an open axle, the tire with the most traction gets the least amount of power. That amount of power is dependant on how much traction is available to the other tire. If one wheel is in the air, the grounded tire will get zero torque. Tire slippage transfers power to the other wheel.

With an axle with a limited slip, the tire with the most traction will get a percentage of power greater than an open differential, yet less than 100% of the available torque. Tire slippage again transfers power to the other wheel.

With an axle with a locker or spool, the tire with the most traction gets a much larger % of the available torque. In a scenerio where one tire is airborne and the other is grounded, the grounded tire carries 100% of the availble torque. If that tire slips and regains traction, the amount of torque exerted on that axle is a factor larger than 100% of the available torque due to the moment of the tire/wheel.

Axle halves rairly break in the open or LSD scenerios, but often break in the Locker/Spool scenerio because that scenerion is where 100% or more of the available torque is exerted on the axle shaft.

Why lock a D35? Because it suits your needs at the time. Lots of folks with D35s, lockers and 31's out there who have had no problems and have enjoyed the comparative ease of which they now get around off-road.

boomhauer
January 17th, 2006, 07:07
Very well put but damn did I go crosseyed reading it. so I will dumb it down a bit cuz I am in the mood.
is it the theory of relativity? Power takes the path of least resistance...
in an open diff that path is balance between both wheels. when one wheel spins it is evident that is the path of least resistance.
in a limited slip rear end, a small amount of resistance must be maintained on both sides of the diff to allow the clutch pack to tighten up and and limit the slip to the path of least resistance. a limited slip diff will only transfer a % of the power to the path of greater resistance.
a spool and a locker will transfer 100% of the power to both sides unlike an open or LS diff. a locker does not allow a wheel to travel slower than the carrier, only faster so it unlocks to do so.

a locked 35 is weak in 2 major ways that causes problems. the spider gears in an open and trackloc 35 have a tendancy to break a tooth.
the housing is on the flimsy side. not a big deal with an open diff. but can wear out clutch packs sooner.
Axle shafts need to be perfectly in line with a locker. a bent tube will force the shaft to misalign the locker leading to a broken locker.
Zuk, that was put very well.

X2 U2 RawB. Now that makes sense.

Lincoln
January 17th, 2006, 18:57
That price was from calling around to the local junkyards (North West, Hill Top, Durkalous (sp?), etc.). Price depended on exact vehicle/year/mileage/condition, but that’s the right ballpark. I was getting quotes of $400 for a pos Dana 35 with 4.10s. :scared: You can get the 8.8s out of Rangers for $400, but they have drum brakes. I think that the junkyards have caught on that people want the Explorer 8.8s because they have disc brakes. I already talked to Oddball about getting one and I’d rather not give up my first born. :rolleyes: Do the JY prices go down in the winter or are they always high? Who was selling an 8.8 for under $200?

Take a look at www.car-parts.com. Nortwest is listing three with 4.10's for $400. Stock numbers Y392 ('98), Y87 ('99), and Z459 ('00).

The are showing a bunch with 3.55's and 3.73's for $350.

Search for a '95 Explorer axle assembly rear.

If they want to jerk you around see what you can get one out of Seattle for too. Not out anything but a phone call.

Wiley Coyote
January 17th, 2006, 22:08
Take a look at www.car-parts.com. Nortwest is listing three with 4.10's for $400. Stock numbers Y392 ('98), Y87 ('99), and Z459 ('00).


Thanks for the link. That’s a lot different than they were quoting me on the phone.

mattak
January 17th, 2006, 22:45
do you have any buddies with junk at there house.... i pmd a couple of them i bet i can find an 8.8 in a matter of 3 days for under 200

5-90
January 17th, 2006, 22:53
Production? Dana 80, Rockwell 2.5-ton, Rockwell or Eaton 5-ton axle. One-off? Design it - from a clean sheet of paper...

5-90

Whats stronger than a Dana 70? how about a 40 spline gun drilled ford 9' or Dana 60... hasta

JLane99XJ
January 17th, 2006, 23:19
what's stronger than a D70?



a gm 14 bolt

Dingo509
January 17th, 2006, 23:27
Whats stronger than a Dana 70? how about a 40 spline gun drilled ford 9' or Dana 60... hasta


This might be but im not too sure

http://hutnyak.com/MINExpo/Trucks/Caterpillar.JPG/797/CAT797RearSus1.JPG

Cat 787 rear axle BTW those tires are 13' (yes feet) tall

Dingo

Mr.OverKill
January 18th, 2006, 00:46
This might be but im not too sure

http://hutnyak.com/MINExpo/Trucks/Caterpillar.JPG/797/CAT797RearSus1.JPG

Cat 787 rear axle BTW those tires are 13' (yes feet) tall

Dingoi was going to say Sterling 10.5 out of an F250 or 350 :o but now that seems a little inadaquit ( sp? )

JLane99XJ
January 18th, 2006, 01:41
whats the WMS to WMS measurements on those??

LOL

MudDawg
January 18th, 2006, 05:21
I got a really clean assembly out of a '97 exploder for $250.00 delivered.
Try www.getusedparts.com they link to a pile of yards. Fill out the form and in a matter of hours you will get e-mail bids from a pile of places.