10.25 LSD rebuild

Thewespaul

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I’ve had really good luck with the factory lsd, the first gens not so much, but the second gens that are in the obs trucks work great, I can hit the nitrous in the shop truck in third and burn both tires evenly. My driveway is gravel and I often have to pull off into the clay for someone to come the other way, as long as I leave one tire on the edge of the gravel it won’t spin a tire at all. If I do that in our 03 superduty you gotta put it in 4x4 low because it just spins one tire (third gen 10.5)
 

laserjock

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Detroit locker... problem solved ;Poke.

i had mine rebuilt and it works ok in perfectly even terrain. like dirt and snow if its the same on both tires itl work. ice and snow yer stuck fer sure. take a turn in the rain and give it the go juice yer one tire peeling outta there.

i know there expensive but worth the money and i think we all know when you get stuck its never text book. with a Detroit if one tire is on ice and one on dry pavement you can still pull the trailer.
In this pavement princess??? About as far off road as this thing gets is spotting the camper in the yard for winter.

If it were 2wd I’d say that’s the way to go. I got that extra lever on the floor if I need it though. After rebuilding my 8.8 it worked great. I think it will be fine if I just get it back stock.
 

ifrythings

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I’ve rebuilt a few 10.25 lsd, first time was utter hell, second time I figured out that you don’t try and put everything back in at the same time. Pretty easy to take apart, everything rolls out fairly nicely, when you go to put it back together put the side gears with clutches in and roll just the spider gears in with out the cone washers. Now compress the clutches with a few metal bars and a bolt and the spider gears will get enough play where you can slide the washers in and you can finish up the install. If you try to roll everything in together it turns into a nightmare!

Also don’t expect much from the rebuilt lsd, all I found was that in winter the back end just slid sideways and on wet grass the backend just bounced, had to use (2wd)4low to move. If I were to do it again I’d put in a truetac or Detroit or e-locker from a 2011+ 10.5 and never have to worry about it again.
 

laserjock

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I remember a similar fiasco doing the 8.8. I had to put the side gears in and then I think I had to use a bolt and some washers to compress the side gears to get the spider gears to go in. It took several tries rolling them in to get them in the right relative spot I think. There’s a write up here somewhere. Someone told me it was completely different than a 10.25 at the time but I really don’t think they are that different other than how the axles are secured.
 

ifrythings

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The 8.8 and 10.25 are very similar in design expect you don’t have to deal with that Z spring that the 8.8 has.

The 8.8 I’ve done wasn’t too bad to get everything to go in at once but the 10.25 is way to tight to do it all at once. I found it easier to put everything but the spider gears thrust washer in then compress the clutches and slide the thrust washers in.

If your pulling the carrier to do this and you have a spare axle kicking around you can make the “special” ford tool which is just a pice of axle shaft with a square end to fit in a vice so you can turn everything into place.

Note: when I didn’t mine it was a carrier swap so I did the clutches on the bench then swapped carriers, maybe harder or easier if the carrier is in the axle though I’m not sure.
 

laserjock

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That spring about whooped me. I finally took a rubber hammer, lined it up and gave it a big whack. After about 3 tries flinging it across the garage it went.
 

Conky

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Also don’t expect much from the rebuilt lsd, all I found was that in winter the back end just slid sideways and on wet grass the backend just bounced, had to use (2wd)4low to move. If I were to do it again I’d put in a truetac or Detroit or e-locker from a 2011+ 10.5 and never have to worry about it again.

Slid sideways or bounced lmao
Yup thats what they do when working good
 

riotwarrior

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Dont soak clutches in gear oil

Use friction modifier to soack clutches...then add remainder or...required amount to lube.

Check if u use synthetic as that could negate adding the modifier.

IIRC Ford zpecs syn fluid for LSD ....could be wrong but doubt that.
 

Thewespaul

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Dont soak clutches in gear oil

Use friction modifier to soack clutches...then add remainder or...required amount to lube.

Check if u use synthetic as that could negate adding the modifier.

IIRC Ford zpecs syn fluid for LSD ....could be wrong but doubt that.
You’re right about that, I always use synthetic in these so I just use the gear oil.
 

BamKat

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Mike I’ve got the manual for the sterling rebuild that has all the torque specs and tolerances if you want, I can take pictures for ya
Hello! I am currently rebuilding a sterling 10.25 and have been browsing here for information. Can you send me the pics of the sterling rebuild manual that you said that you have. Thanks!

My rear end ended up being complete toast. I bought another off craigslist and it looks like it sat in someones pasture for 10 years..lol I took it all apart and it looks pretty good however it looks like I'm missing the seal that goes around the axle when being slid back into hub. I also need the torque specs.

I'll be honest... I'm just a YouTube mechanic and I have gotten in over my head a few time (you can see from my other threads haha). They just make it look so easy...but often times they don't show how to put everything back...[emoji23]

My truck is a 92 f250 7.3 idi 5 speed. It had a 4.10 and I really liked it. I went with the 3.55 because I found it for $100 and the 4 junk yards that I went to wanted $600.

Any suggestions would be great! Thanks in advance for any replies.
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Thewespaul

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Hello! I am currently rebuilding a sterling 10.25 and have been browsing here for information. Can you send me the pics of the sterling rebuild manual that you said that you have. Thanks!

My rear end ended up being complete toast. I bought another off craigslist and it looks like it sat in someones pasture for 10 years..lol I took it all apart and it looks pretty good however it looks like I'm missing the seal that goes around the axle when being slid back into hub. I also need the torque specs.

I'll be honest... I'm just a YouTube mechanic and I have gotten in over my head a few time (you can see from my other threads haha). They just make it look so easy...but often times they don't show how to put everything back...[emoji23]

My truck is a 92 f250 7.3 idi 5 speed. It had a 4.10 and I really liked it. I went with the 3.55 because I found it for $100 and the 4 junk yards that I went to wanted $600.

Any suggestions would be great! Thanks in advance for any replies.
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Shoot me a pm with your email address and I’ll send you a pdf of the manual. Did you check the wheel seals that are on the axle for a part number?
 

david85

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I'm not an oil expert by any stretch but when I switched to synthetic, I had to use the friction modifier even though the bottle claimed it wasn't necessary. On a cloverleaf style freeway exit, I could hear the rear end bumping as the clutches tried to figure out what the heck was going on. A full bottle of the ford friction modifier and it was perfect again.

A locker is something I have pondered over the years though. LSD requires a certain amount of slip in order to grab the loose wheel. That's more than enough to get a 2wd really dug in. They are fun on wet pavement though.
 

BamKat

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Shoot me a pm with your email address and I’ll send you a pdf of the manual. Did you check the wheel seals that are on the axle for a part number?
Thank you! After doing more research, I was looking at the wrong diagram. Nothing is missing. This is what I have:
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hesutton

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If I were to do it again I’d put in a truetac or Detroit or e-locker from a 2011+ 10.5 and never have to worry about it again.
Amen to that. I ditched the stock LS for a TruTrac on the F250 years ago. Works better for me than the LS did. It will bark the tires occasionally on tight turns, but not enough to be a problem.

Heath
 
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u2slow

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A locker is something I have pondered over the years though. LSD requires a certain amount of slip in order to grab the loose wheel. That's more than enough to get a 2wd really dug in. They are fun on wet pavement though.

The trac-lock (trash-lok) the Ford unit is modelled after doesn't need any 'wind-up' to catch... like a GM gov-bomb for example.

When I realized the one in my F350 only held tight when the truck was empty, it was time to go. Found a NiB Detroit and never looked back. Finally had traction that didn't go away with a ton of payload in the bed.
 

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