My Rear Diff Went 🤢🧨💥🤮💔 - And How To Proceed?

[Billy Cranston]

I was happily going down the Freeway when my bad choices caught up to me. Then pow, I hear a loud grinding coming from under my truck so I pulled into the emergency lane. My truck wouldn't move or roll in neutral even. So I called AAA and they got me to my shop but since it wouldn't move I let the guy try to bump it off. To our surprise whatever was seized in the differential broke free and allowed me to roll off the back of his tilted flat bed. And now...

I need some major parts!! I guess ignoring a pinion seal leak is a bad idea.


Is there a good rear diff rebuild guide for the Fx4 LVLII?

I know I need a new carrier but Torsen also has a thrust block for sale and I'm not sure if I need to buy that or if it's in the carrier or..? my old thrust block pooped out when the gears made the inspection port and it's all chewed up.

I'll be opening it up tomorrow to see how everything looks / what if anything is salvageable..

 

[Curious Hound]

When I bought new gears for my axles, good instructions came with the new gears and also with the rebuild kits. I imagine that if you have to buy s new Thorsen, it should come with instructions also. Go watch a few videos on setting up differentials before you decide to do it yourself. You'll need a few special tools. Dial indicator with magnetic base. Good way to accurately measure pinion depth. Torque wrench that goes up to at least 300ft-lbs (250 isn't high enough), another torque wrench for measuring pinion preload (1/4" beam or dial type. Not a clicker) and a way to hold the pinion flange while torqueing the pinion nut. This is a substantial job and it must be done right unless you want to do it again.

 

[Eddo Rogue]

Proceed over to a rear end shop...Should be well under 1000 bucks including a nice complete rebuild kit (w/ bearings and crush washer).

Its not a difficult DIY job, if you can read a dial indicator and a gear pattern the rest is pretty much standard wrenching...I learned give the crush washer a little pre whack to help it crush, and mind the break in procedure.

 

[Billy Cranston]

update:

My axles are torn up at the ends, my ring and pinion too. My tone ring looks alright but I'm going to have to change the whole thing anyway, might as well get that




I'm going to have to assess whether to let a pro do it once I finish my parts buying spree..

 

[Curious Hound]

Might be cheaper to get a new axle. Is that a crack in the carrier in the second picture?

 

[Northidahotrailblazer]

Time to upgrade to a 31 spline disk explorer 8.8. Way cheaper to swap diffs than a rebuild, just my .02 cents. I can buy a disk 8.8 for less than $200 bucks pulled. There was one on my facebook market place for $100 bucks the other day.

 

[Shran]

Wow. Looks like you had quite a bit of oil in it, judging by the puddle? I am guessing something other than oil starvation caused that to happen.

If you decide to fix the axle you have instead of just replacing it, I would check over everything really well. Axle shafts/bearing caps/etc... a lot of stuff could be damaged there, including the housing itself.

 

[Garth Libre]

At my local junkyard I've seen more than a few of the rear ends you're looking for. I believe the price for these is $200 and I assume they offer some kind of a warrantee. You'll need a truck to get it of course and I've seen it will take you an hour to get it out and a few hours to get it in. It might be worth it to go with a friend and pull one. I'm pretty sure there are inspections and tests you can do to determine if you are looking at a good one worth buying. In any event it will take less time and talent and tools to swap one than to rebuild one.

 

[Billy Cranston]

Might be cheaper to get a new axle. Is that a crack in the carrier in the second picture?

The Torsen assembly blew up! cast pieces and helical gears were everywhere when I opened it up.

an axle swap will for sure save me a bunch of money. Unfortunately I can't find a local axle that would accept the torsen through car-part... I want to keep it original so I'm going to spend 5x more .



I found a business that specializes in rear diffs so I'm going to remove it and let them tell me what needs to happen. I'm sure every part is toast. They told me not to buy anything before they inspect it. I was going to buy a rebuild kit and everything else but I'll see what they have to say.

I can't believe I didn't upload the main pic!

 

[Curious Hound]

The Torsen assembly blew up! cast pieces and helical gears were everywhere when I opened it up.

an axle swap will for sure save me a bunch of money. Unfortunately I can't find a local axle that would accept the torsen through car-part... I want to keep it original so I'm going to spend 5x more .



I found a business that specializes in rear diffs so I'm going to remove it and let them tell me what needs to happen. I'm sure every part is toast. They told me not to buy anything before they inspect it. I was going to buy a rebuild kit and everything else but I'll see what they have to say.

I can't believe I didn't upload the main pic!
View attachment 85011

Yup. Dat’s broke.

 

[4x4junkie]

There was a recall on those Torsen diffs on 2002 & 2003 models for that very issue, although in their idiocy Ford only applied it to manual-trans trucks. I'm suprised they continued to use those diffs at all after that.

Hopefully upon getting it rebuilt, you'll have the newer (updated) one.

 

[Josh B]

There was a recall on those Torsen diffs on 2002 & 2003 models for that very issue, although in their idiocy Ford only applied it to manual-trans trucks. I'm suprised they continued to use those diffs at all after that.

Hopefully upon getting it rebuilt, you'll have the newer (updated) one.

If that's the case he might find one of the replaced ones if there's any way of knowing what to look for, and surely there is

 

[Garth Libre]

The Torsen assembly blew up! cast pieces and helical gears were everywhere when I opened it up.

an axle swap will for sure save me a bunch of money. Unfortunately I can't find a local axle that would accept the torsen through car-part... I want to keep it original so I'm going to spend 5x more .



I found a business that specializes in rear diffs so I'm going to remove it and let them tell me what needs to happen. I'm sure every part is toast. They told me not to buy anything before they inspect it. I was going to buy a rebuild kit and everything else but I'll see what they have to say.

I can't believe I didn't upload the main pic!
View attachment 85011

I wish someone would explain to me how in the world these junkyards even know what they have on stock in the fields. My local Chattanooga U Pick has many thousands of cars. If I go to the Ford section there are often Chevy's and Japanese trucks scattered in. Do they actually know what differentials their 30 Ranger and two dozen F150's have? I doubt it. As you check out they don't even ask which car you took what from. They just go - "oh a differential that's $xxx", and half the time I think they're just making up a price. It's total chaos. The last time I went, I had a rubber trim gasket and they couldn't even be bothered to charge me and when they rang me up for a body part they didn't even notate it. They just came up with a number.

 

[Eddo Rogue]

I wish someone would explain to me how in the world these junkyards even know what they have on stock in the fields. My local Chattanooga U Pick has many thousands of cars. If I go to the Ford section there are often Chevy's and Japanese trucks scattered in. Do they actually know what differentials their 30 Ranger and two dozen F150's have? I doubt it. As you check out they don't even ask which car you took what from. They just go - "oh a differential that's $xxx", and half the time I think they're just making up a price. It's total chaos. The last time I went, I had a rubber trim gasket and they couldn't even be bothered to charge me and when they rang me up for a body part they didn't even notate it. They just came up with a number.

Some would rather waste their time asking the idiot home depot employee rather than looking for it themselves...either way, time and money will be wasted.

 

[Garth Libre]

Some would rather waste their time asking the idiot home depot employee rather than looking for it themselves...either way, time and money will be wasted.

At my local big box hardware stores and smaller places like True Value, the employees all seem pretty sharp.