Rear diff 10.25 locked up

brockshields38

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Hey guys so long story short my rear diff locked up on me.
Long story long, I was driving into work a few weeks ago and using cruise control as always. I had that set to 99km/h (61-62mph) and my cruise is rather good at maintaining speed I never see it differentiate more than 1mph when on grades. So I was driving along on flat grade and felt my truck accelerate I looked down it was all the way down at 95kmh, and continued to accelerate up to 103 before settling down again at 99 where I set it. About another 1/2mile further down the road coming up to a stop light that was red and right after I finished shifting down into 4th the rear end locked up and started skipping so I jammed in the clutch and skidded off onto the shoulder. I hopped out and took a peek under the back and there was a small amount of smoke coming from the front of of the diff at the yoke. So called up a flat bed got it hauled back to my house dragged on and off the deck. So I’ve finally gotten up the nerve to take a look and deal with the heartbreak expecting to see shrapnel fall out as I took the diff cover off. But to my surprise there was no chunks on metal no chunks out of any teeth, but also no fluid. After further inspection, there is a small pinhole in my diff cover about halfway up from the bottom. So where should I go from here I’m not too we’ll versed with differentials and transmissions but I’m hell bent on figuring it out. Should I start pulling out bearings? Would the issue remain within the diff housing or could it extend out the axles.

Any and all help is appreciated!

1996 F250 7.3 ZF5 3.55LS Dana 50 IFS and Sterling 10.25” rear
 

Peroni

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Probably cheaper to pick up a good used axle but I'd start by replacing all the bearings, even the hub bearings. Gears might be toast as well from running without oil.
 

brockshields38

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Ok so replace all the bearings. How many are there in the diff itself 2 at the sides and 2 out the front to the yoke?
 

Peroni

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Yes 4 in the pumpkin itself and two each per hub. Timken DRK314MK has everything you need for the diff and input shaft. From personal experience I'd use the Yukon super shims in the diff, made my install very easy. Also a crush sleeve eliminator if you don't want to mess with the sleeve. Yukon might have a master rebuild kit with everything you need, I'm just not sure who makes their bearings.
 

brockshields38

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Ok well I went back at it for a bit. The carriers I think are fine, it’s the pinion that’s causing issues. The outer edges of the ring have a bit of wear to them not sure if there’s any amount that’s allowable or if I should be replacing ring and pinion along with the bearings..other than that everything seems to be tip top. Spider gears look great still
 

Bugman

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I think that I would actually find a good used rear end and swap them out.

But if you are set on trying to fix it the first thing that I would do is to drop the drive line and get the rear end up in the air on some jack stands. Then I would pull one axle and see if things will turn, if not pull the other axle and try again. Then if there is still a problem you are going to have to pull everything out to rebuild it.

Here is a diagram for you to look at as to where the bearings are.

10.25inch-sf.jpg
 
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brockshields38

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I have the back end in the air. Axles move up until it gets to the ring and pinion. Spider gears move like I said earlier. Today I’m pulling everything out and will update once everything is gutted. You guys keep saying buy a used axle but you don’t know how hard it is to find these trucks around here never mind one that’s got the same setup I do.
 

Bugman

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It might help if we knew what kind of set up you have.

On the rear end it doesn't need to be from a diesel truck just get the year range and it will be fine. The only real differences will be limited slip and the gearing.
 

8WR_ZJ

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In my opinion you will need to replace everything in side of the housing except maybe the axle shafts. More than likely the R&P will howl like a wolf if you try to reuse it. Also if it is the factory LS you will need to rebuild it they do not like excessive heat.

Sent from my SM-G965U using Tapatalk
 

rrchlin

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People are saying buy a used rear because 10.25s are 150-200 on average. It will cost you more than that in bearings (that are I think press on, press off), and then ring and pinion and required tools. Crush sleeve eliminator.. Then hub bearings.

Id like to learn to set up diffs for fun. But not on a time crunch.

For a 10.25 swap.. All youll need is maybe new u-bolts and possibly a section of brake line if you damage a piece, a $4 gasket and some gear oil. Not required but the $100 HF 12 ton jackstands are the perfect size jackstand for our trucks frame.
 

m j

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gearing was basically only two choices in that era, its either 3.55 or 4.10.
so that is a non issue. LS can be swapped with 4x4 with zero issues. me personally I throw the factory carrier in the trash and install either a detroit or grizzly.

if you ran the dif out of oil enough to lock it up I would find a different housing to rebuild and swap in.

where in the world are you that finding a 10.25 is difficult? you want a 93-97 version.
in most areas you cannot find people to take these axles away for free, I wouldnt pay more then $50cdn for one. (ps- I am swapping mine out for a 10.5 so you can have my housing and gears for free if you are near, not the Grizzly though)
 

brockshields38

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MJ is she a 3.55? I’m 2 hours north east of Toronto. It’s not completely locked up, she’ll move if I dump the clutch but it’s definitely cooked
 

freddie

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Check Car-Part.com .. I was going to check for you but I don't know your location, eh?

I rebuilt my 10.25" using all Timken bearings and seals, it was not cheap. Then there's the cost of ring and pinion setup unless you do it yourself. I paid a shop to do it right, because I didn't have the time to "do it right", and didn't want to run the risk of being stranded or trashing all the new parts I'd just put in it. That's why everyone is suggesting finding a used 3.55LS axle.
 
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brockshields38

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Ok well I finally found an axle. Cost me way more than it should’ve but now I’m faced with the dilemma of either swapping the parts out or swapping the whole axle. The one I bought is out of a 97, full floater like mine, the only difference is it’s an open diff where as mine is LS. So to my question. Will the pinion gear from the open diff work in my LS??
 

brockshields38

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Awesome I’m about to go start opening up the new one. Been six weeks without my truck I’m really missing her lol
 

brockshields38

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Well the new diff is gutted and I’m rather impressed with the shape of the insides. So if my carrier lines up I’ll use the new carrier, rig and pinion. The inner pinion bearing is good., but I obviously mangled the outer while prying out the seal so I need to order one of those. Does anyone have the part numbers for these?
 
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