Where do you jack up your Expedition?

[drewactual]

that diff case is hardened steel... it could support two trucks and not whimper... if it ever encountered enough weight to impact it, it would snap/crack- not bend.

it's perfectly acceptable to jack a rear off the ground using the differential as a lift point. so long as the front is on the ground it won't even teeter.

 

[and0r]

Yeah that seems to be the consensus, but I really don't feel it is proper. Do you know exactly how much weight is being put on the Jacking point?

The tolerances for the differential seem razor sharp,
...a precision component

 

[drewactual]

put it this way:

it's thicker than an icebreaker ships hull... it's thicker and made similar to a engine block, which has several thousand fast burns/slow explosions, however you want to look at that, per minute... it's thicker and made of stronger material than the hydraulic lift arms used on a two or four post lift. if you shot the perimeter (case not face) with a .50BMG, you may crack the casing but nothing short of a 50BMG would do it... the casing doesn't warp and it doesn't flex... you could hit it with all your might with a sledge hammer while it's turning the axles, and it wouldn't phase it...... they are incredibly strong.

it's really not up for any kind of debate- that casing is stout and capable of being used as a lift point all day long with a full capacity load and full tank of fuel.

 

[Big Brian]

in one of my previous jobs,I worked at American Axle in the research lab. One of the tests I did was called "beaming" We would take a complete rear axle assembly and mount it in the dyno so that it was supported by the spring perches. Then a HUGE hydraulic ram was setup to push down on the top of the differential. It would cycle up and down for days trying to bend the axle until something broke.

The axles never bent, the spring perches and welds were always the first to go. We would weld new perches on and keep going until the test was finished

so jacking the vehicle up by the diff will not do diddly to it.

 

[stamp11127]

Wow fantastic job - paid to break stuff.....

 

[Bedrck47]

Wow fantastic job - paid to break stuff.....

Just think WE have members on this forum that DO NOT charge or get paid to break stuff
But they want FREE advice on how to fix what they broke

 

[Big Brian]

Wow fantastic job - paid to break stuff.....

lol I have stories...

For a period of time I ran driveshaft dynos. They are called rotary actuators. They would try breaking a driveshaft by bolting one end to a stationary plate and the other to the actuator. Twist back and forth thousands of times until something breaks.

Sounds like fun until you have 6 of them running and one after another keeps breaking the u joint before the driveshaft (then you have to put a new u joint on) and it keeps you running back and forth tending to the "crying babies" as I would call them.

And talk about noise!

glad I got away from that kind of work!

 

[and0r]

put it this way:

it's thicker than an icebreaker ships hull... it's thicker and made similar to a engine block, which has several thousand fast burns/slow explosions, however you want to look at that, per minute... it's thicker and made of stronger material than the hydraulic lift arms used on a two or four post lift. if you shot the perimeter (case not face) with a .50BMG, you may crack the casing but nothing short of a 50BMG would do it... the casing doesn't warp and it doesn't flex... you could hit it with all your might with a sledge hammer while it's turning the axles, and it wouldn't phase it...... they are incredibly strong.

it's really not up for any kind of debate- that casing is stout and capable of being used as a lift point all day long with a full capacity load and full tank of fuel.

no, steel is not made of diamonds.
and the only reason why its thick and hard is to prevent it from deforming, under an evenly distributed load, even by just a single millimeter.
the load of the differential and axle is spread evenly across the sides of the differential and across the ends of the axle.
really look at the jacking point when you jack the differential up. much force is being exerted onto a very fine point. im quite sure this is enough to deform the housing, even by just a single millimeter, either directly or by overall radius of the housing.

 

[and0r]

in one of my previous jobs,I worked at American Axle in the research lab. One of the tests I did was called "beaming" We would take a complete rear axle assembly and mount it in the dyno so that it was supported by the spring perches. Then a HUGE hydraulic ram was setup to push down on the top of the differential. It would cycle up and down for days trying to bend the axle until something broke.

The axles never bent, the spring perches and welds were always the first to go. We would weld new perches on and keep going until the test was finished

so jacking the vehicle up by the diff will not do diddly to it.

i commend your position at some kind of axle testing facility, however these supposed tests do not prove anything.
once again i need to repeat myself - the differential is a precision component. there is no way any of those "indestructible" differentials are going to last on the road more than 5,000 miles after running those tests. its quite silly of you to think these tests would even prove anything. yes, the housing wasn't completely destroyed, so what. this proves nothing. it seems that you are really going out of your way with poor facts and data. no offence

 

[Big Brian]

oh deary me

another expert

if you "theory" was true the highways and byways of this country would be strewn with vehicles with bent axles all over the side of the road

oh deary me