When I changed the gears in my 59 I was lucky enough to run into this design. Such a great piece of engineering to work with and so simple. Still works great!
Thanks Jeff, I always wondered how those worked, but have not seen to many third members apart. I never was the one working on them then. I did understand how the open diffs worked, but not the posi units. Thanks again for the enlightenment.
i never knew, i allways wondered how it worked... looks like it will be so tight wen everything is new, even if it is not gritty.. Thanks, I learned something
Man that's a cool piece of history, sometimes I wished my 55 GMC has a posi rear end. It would help a lot when I'm one wheel peeling trying to get myself unstuck on the muddy farm yard. Even the trusty old whitewall mud and snow tires couldn't get me rocked free, a Posi would be awesome.
@Pat Ball yeah thats true but I really cared about the originality of the truck. It still has it's original engine, drive line, suspension and brakes. Its still got those massive 11inch manual drum brakes.
Hi Jeff, if this video is about Hauppague, NY, well that's in my neck of the woods. No disrespect, it's pronounced ( hop- hog). American Indian's named that town back in the day. Long Island has many towns that bear American Indian names. Just thought I'd pass along a little history along, if I may. Out of state truckers would struggle with these towns on the C.B. and I'd try to help them out.. Great video, as always Jeff!! Thanks for helping me understand the differential.
And the Academy Award for Best Information goes too. Jeff Bradshaw.... Applause by the viewers YEAH JEFF YEAH JEFF. Jeff appears at the podium and thanks to his fans. And that's the way it went.
This is a clutch type lsd, newer stuff could be this, or a viscus or helical lsd. I jave no idea how either of those work though, or what kind an Alfa may have, I would suppose it would depend on the year.
@@mostlymoparih5682 Worn out but all it takes is one warmish day and they'll be back. Just like politicians begging for more money to waste. Lots of similarities there.
Are these Eaton limited slip units used in the "Corporation" rear axles? All of the '60's 1/2 ton Chevy' and GMC's I've come across have had Spicer axles for posi applications.
Do you know the clearance tolerance for the side to side movement for the limited slip carrier clutches and gears ??? That would really help me out Jeff.One last thing, can you still get parts for the old rear ends ???? Thanks
@@Talisman-tb6vw I see !! Thanks for the reply. Why would anyone expect the driver to know about applying the brake?? A "thought process" that has lead all the way to "self driving" cars. ;o(
@@pappabob29 , I believe it was in the owners manual if you ordered your vehicle with the Eaton posi. I learned it from my dad when he was teaching me how to drive. The brake trick also works on non-posi diffs too :D
Not unlike a Dana 44 or Mopar 9.25. The problem is that the current Mopar, manufactured by ZF, kills the clutches/plates in al little as 30K miles and requires the removal of the carrier to replace. Pinion depth is usually still good but now you have to set side preload with those ever so cooperative threaded adjusters.
Have seen 4x4 F-150 without locking rear differential, and it is awful in 2 w drive. Do you know if locking rear diff would make that truck a real 4 x 4 or is it really a 3 wheel drive truck when 4 x 4 is engaged? Didn't know if both axles lock when in 4 x 4. I assume posi-traction option makes good sense when ordering any type of new pickup truck.
Jeff did they use a friction modifier in the fluid back then? I'm guessing the clutch material back then was different and most likely the engineers didn't care about chatter?
You can but you would need to install an entire rear end to do that. I dont think its a direct bolt in but I am not sure. This is the only posi that can be added to a 1955 to 1962 Chevy 1/2 ton truck.
hi jeff i disagree the centrifugal force would force the spider gears outwards .so thus physics.as u apply them are forced out the window ..so look forward to ur next vid How to fix a broken window ...ha ..now go find the spring for that posi unit please sir !!!!
Correct, but this is not a posi, or "positive traction" carrier. The "Limited Slip" differential allowed the gears to walk around the pinion when unloaded. You can turn one wheel on a limited slip like this when one wheel was in the air. With springs in the clutch pack, the axles are bound by the clutches full time and you cannot turn one wheel. In theory, the limited slip differential acted like an open differential under light load. It would actually spin one wheel when stuck. Once you applied the parking break, the resistance of the brake cause torque to be applied between the carrier and the side gear, thus forcing the side gears outward into the clutch pack. If you were on dry pavement and pulled a holeshot, it would spin both tires every time because of the high toque load being applied.
The square spacer is indeed factory. The axles are semi-floating, so there is nothing to prevent end play inward. The c-locks prevent the axle from coming out. If the block was not there, the axles could move inward, contact the pinion pin, and drop the c-locks out.
Wondering... You start the video with 2 of the gears removed already making it difficult to see how my same Eaton unit is supposed to come apart??? Mine doesn't seem to be coming apart in reverse order of how yours goes back together... Also, I have a few of these units (some as parts units) currently where I could use a new pin and block. Also, does any company make new clutches for these and shims? How many spacers are supposed to be use when putting something like this back together to use; you mention the necessity of using shims but don't give much more info.
At 3:30, each side has 4 clutches, 3 discs. At 9:19, the shims go between the last clutch disc and the carrier. The carrier is cast iron and the clutches, plates (discs) and shims are steel. The clutches would chew up the cast iron in short order, so a steel shim is installed. At 10:30 is where your reverse order would remove the pinion gears. The side gears will practically fall out once the pinions are removed, which is why I has to twist-tie them in. From step one, remove the retaining bolt. Remove the pinion pin and the block will fall out. (1:30) Rotate the side gears in opposite directions until the pinion gears are fully exposed. Once expose, they will drop out. Once the pinion gears drop out, there is nothing holding the side gears in with possibly the exception of the friction of the steel "U" cap over the clutch plates that prevent them from cutting into the cast iron of the carrier. (6:30)
@@seannielsen4696 None of the parts are available. A decent working unit is worth a grand. They fit any of the "banjo" housings from the half tons from 55-62. The "U" caps you'll have to fabricate. I was going to use Hardox. There's a local dump bed manufacturer that I can get scraps from. Just measure the width of the tabs on the clutches and the width of the socket in the carrier and do the math. That will give you the thickness you need. The are no interchangeable parts with any other posi rear. With the advent of CNC machining and plasma cutting, It shouldn't be impossible to fabricate parts for these now. As to the pin for the pinion gears, that can be welded and machined back to specs. The blocks can be turned 90 degrees and run for your lifetime!
Because the differential housing is reacting to the torque of the drive shaft. Because both wheels have traction the differential housing is trying to turn in the opposite direction of the drive shaft resulting in more downward pressure on one wheel which means less pressure on the other wheel which will break traction and spin. With everything equal that will always be the wheel that spins.
The Differential is such a clever ancient design, it still gets the job done all these years later :-D.
I'm still impressed by it.
When I changed the gears in my 59 I was lucky enough to run into this design. Such a great piece of engineering to work with and so simple.
Still works great!
Brilliant design. And to think this was all conjured up and made to work in the age of the slide rule.
I never get tired watching Jeff do stuff... Best wishes xCop
Thanks Jeff, I always wondered how those worked, but have not seen to many third members apart. I never was the one working on them then. I did understand how the open diffs worked, but not the posi units. Thanks again for the enlightenment.
That's a great piece of good old American Elderly Iron and an excellent tutorial! Thanks, Geoff, and Merry Christmas!
i never knew, i allways wondered how it worked... looks like it will be so tight wen everything is new, even if it is not gritty.. Thanks, I learned something
Excellent explanation of the clutch style LSD, thanks for taking the time
Another excellent explanation and knowledge. Along with your usual fine video and description.
It's so nice that almost everything is invented already so we just have the possibility to enjoy the results!
Man that's a cool piece of history, sometimes I wished my 55 GMC has a posi rear end. It would help a lot when I'm one wheel peeling trying to get myself unstuck on the muddy farm yard. Even the trusty old whitewall mud and snow tires couldn't get me rocked free, a Posi would be awesome.
@Pat Ball If only I could find a truck that old in the junkyard!
@Pat Ball yeah thats true but I really cared about the originality of the truck. It still has it's original engine, drive line, suspension and brakes. Its still got those massive 11inch manual drum brakes.
I've seen the newer Easton with the springs in it but never this older design. Thanks
Awesome video!! My 1969 chevy 3/4 ton 4x4 has an HO72 rear end not the Dana. It came stock with the Eaton no spin differential and 4:56 gears.
Always wondered how that worked, THANKS!
Just like that, Thanks Jeff. Don't see that every day.
Reminds me of the good old days but there was a lot of colorful language.
Always been black magic to me. Thank you for the tutorial
Excellent description Jeff. Very cool 👍😁👍
Thank You Sir
Keep them coming!
Have you been watching This Old Tony videos?? Great presentation. I may actually overcome my fear of these things.
Merry Christmas
> Jeff and Your Family > Russ Robinson > Ann Arbor , Michigan
Hi Jeff, if this video is about Hauppague, NY, well that's in my neck of the woods. No disrespect, it's pronounced ( hop- hog). American Indian's named that town back in the day. Long Island has many towns that bear American Indian names. Just thought I'd pass along a little history along, if I may. Out of state truckers would struggle with these towns on the C.B. and I'd try to help them out..
Great video, as always Jeff!!
Thanks for helping me understand the differential.
Thanks Jeff keep on explaining old stuff to us, even if there isn,'t a buyer request, please.
And the Academy Award for Best Information goes too. Jeff Bradshaw.... Applause by the viewers YEAH JEFF YEAH JEFF. Jeff appears at the podium and thanks to his fans. And that's the way it went.
I bet that is delightful when putting it together with the shims.
Yes sir’ee, , nice show n tell! Been a while since I’ve seen that! Preciatecha!
been a while since I've been in a rear end that deep :P lol
Randy Schartiger spend enough time figuring out crush sleeves, shims and pinion depth and preload and you’ll give up on sex completely
not
Thank you, Jeff
Sweet
just a reminder, always check your christmas trees for woodticks and wolverines.
merry christmas!
AND your firewood!
i have never seen this before and always wonderd how it works ! must be same solution for the alfas rear drive with limited slip diffs !
This is a clutch type lsd, newer stuff could be this, or a viscus or helical lsd. I jave no idea how either of those work though, or what kind an Alfa may have, I would suppose it would depend on the year.
@@toddmccarter45 manuel with dry clutch , made from 64 to 92 i belive! 2liter engines 150 hp and 200newtonmeters @4500rpm , rps good in a 1ton car!
Well said Jeff
Thanks, Buddy, for keeping it clean! GBWYall from Us Hillbillies on the Swamp!
Got any swamp flies there big Brother or is it two2 late four4 them?
@@mostlymoparih5682 Worn out but all it takes is one warmish day and they'll be back. Just like politicians begging for more money to waste. Lots of similarities there.
Who would give that a thumbs down? Thanks Jeff
👍👍👍
Nice Job, Jeff! Liked and enjoyed! JJ THX teach.
You're welcome!
You won my giveaway Sir!
Really?
Good stuff sir.
Most excellent, how much more difficult when you put the shims in?
@@grandmasmalibu Thanks for the explanation, would definitely call for using the vice.
Are these Eaton limited slip units used in the "Corporation" rear axles? All of the '60's 1/2 ton Chevy' and GMC's I've come across have had Spicer axles for posi applications.
Good video !!
Do you know the clearance tolerance for the side to side movement for the limited slip carrier clutches and gears ??? That would really help me out Jeff.One last thing, can you still get parts for the old rear ends ???? Thanks
Cool! I diddnt even know theses was a ting
This design seems so simple and reliable. What "advantage" over this design did they "perceive" when they updated it with the springs??
the spring applies the side pressure instead of you applying the brakes.
@@Talisman-tb6vw
I see !! Thanks for the reply.
Why would anyone expect the driver to know about applying the brake?? A "thought process" that has lead all the way to "self driving" cars. ;o(
@@pappabob29 , I believe it was in the owners manual if you ordered your vehicle with the Eaton posi. I learned it from my dad when he was teaching me how to drive. The brake trick also works on non-posi diffs too :D
Owing to last nights ice storm, I positive it was my rear end that hit the ground this morning and not Eaton's. Narragansett Bay.
I feel your pain...
So basically if I wanted to do more burnouts in my limited slips rear end i could take it apart and put more shims I it?
Not unlike a Dana 44 or Mopar 9.25. The problem is that the current Mopar, manufactured by ZF, kills the clutches/plates in al little as 30K miles and requires the removal of the carrier to replace. Pinion depth is usually still good but now you have to set side preload with those ever so cooperative threaded adjusters.
Have seen 4x4 F-150 without locking rear differential, and it is awful in 2 w drive. Do you know if locking rear diff would make that truck a real 4 x 4 or is it really a 3 wheel drive truck when 4 x 4 is engaged? Didn't know if both axles lock when in 4 x 4. I assume posi-traction option makes good sense when ordering any type of new pickup truck.
A posi rear is always beneficial. It's still 4x4 with open differentials as all 4 are being driven.
I never would have considered that a Limited-Slip Differential would have Clutches.
Great stuff Jeff. Now can you tell me why Ford Limited slip additive smells like vomit? Horrible stuff....
Jeff did they use a friction modifier in the fluid back then? I'm guessing the clutch material back then was different and most likely the engineers didn't care about chatter?
Why not use a 10 and a half 14 bolt from a newer gm truck such as 90s or will it not work
You can but you would need to install an entire rear end to do that. I dont think its a direct bolt in but I am not sure. This is the only posi that can be added to a 1955 to 1962 Chevy 1/2 ton truck.
ive been wrong a couple of times before but aren't there supposed to be cupped shaped shims on the smallest gears? the ones the pin goes through.
yes, but i'm sure he just left them out for ease of assembly !
Didn't come with any. I know the open diffs do, but this one doesn't seem to have enough clearance for them.
@@ElderlyIron I've been wrong a couple times before . . .and again today!!
Doesn't mean you were wrong, just means this one didn't have any!
hi jeff i disagree the centrifugal force would force the spider gears outwards .so thus physics.as u apply them are forced out the window ..so look forward to ur next vid How to fix a broken window ...ha ..now go find the spring for that posi unit please sir !!!!
Centrifugal force has nothing to do with it.
@@ElderlyIron i agree ..where is the missing spring assembly..that square spacer on the spyder pin is not factory ..
those old GMs had a few springs.and a plate on each side gear for pressure plate..later yrs had a single spring tenision clip
Correct, but this is not a posi, or "positive traction" carrier. The "Limited Slip" differential allowed the gears to walk around the pinion when unloaded. You can turn one wheel on a limited slip like this when one wheel was in the air. With springs in the clutch pack, the axles are bound by the clutches full time and you cannot turn one wheel. In theory, the limited slip differential acted like an open differential under light load. It would actually spin one wheel when stuck. Once you applied the parking break, the resistance of the brake cause torque to be applied between the carrier and the side gear, thus forcing the side gears outward into the clutch pack. If you were on dry pavement and pulled a holeshot, it would spin both tires every time because of the high toque load being applied.
The square spacer is indeed factory. The axles are semi-floating, so there is nothing to prevent end play inward. The c-locks prevent the axle from coming out. If the block was not there, the axles could move inward, contact the pinion pin, and drop the c-locks out.
Did the Bronco sell?
Not yet
Now do a Locker from a 56 Ford and we will be all set...lol
Wondering... You start the video with 2 of the gears removed already making it difficult to see how my same Eaton unit is supposed to come apart??? Mine doesn't seem to be coming apart in reverse order of how yours goes back together... Also, I have a few of these units (some as parts units) currently where I could use a new pin and block. Also, does any company make new clutches for these and shims? How many spacers are supposed to be use when putting something like this back together to use; you mention the necessity of using shims but don't give much more info.
At 3:30, each side has 4 clutches, 3 discs. At 9:19, the shims go between the last clutch disc and the carrier. The carrier is cast iron and the clutches, plates (discs) and shims are steel. The clutches would chew up the cast iron in short order, so a steel shim is installed. At 10:30 is where your reverse order would remove the pinion gears. The side gears will practically fall out once the pinions are removed, which is why I has to twist-tie them in. From step one, remove the retaining bolt. Remove the pinion pin and the block will fall out. (1:30) Rotate the side gears in opposite directions until the pinion gears are fully exposed. Once expose, they will drop out. Once the pinion gears drop out, there is nothing holding the side gears in with possibly the exception of the friction of the steel "U" cap over the clutch plates that prevent them from cutting into the cast iron of the carrier. (6:30)
@@ElderlyIronIs there any business out there who sells the clutches, disks, and shims? Do these Eaton units fot 1955-1959 or 1955-1962? Thanks.
@@ElderlyIron And does anyone make the u caps?
@@seannielsen4696 None of the parts are available. A decent working unit is worth a grand. They fit any of the "banjo" housings from the half tons from 55-62. The "U" caps you'll have to fabricate. I was going to use Hardox. There's a local dump bed manufacturer that I can get scraps from. Just measure the width of the tabs on the clutches and the width of the socket in the carrier and do the math. That will give you the thickness you need. The are no interchangeable parts with any other posi rear. With the advent of CNC machining and plasma cutting, It shouldn't be impossible to fabricate parts for these now. As to the pin for the pinion gears, that can be welded and machined back to specs. The blocks can be turned 90 degrees and run for your lifetime!
@@ElderlyIron Are even the shims not available aftermarket? How does a person determine how many shims to use? Do you have ANY literature on these?
Limited Slip or Positraction. So what's the diff??? lol!!!
And you're the FIRST!
Now explain why one tire always seems to spin and not the other.
Because the differential housing is reacting to the torque of the drive shaft. Because both wheels have traction the differential housing is trying to turn in the opposite direction of the drive shaft resulting in more downward pressure on one wheel which means less pressure on the other wheel which will break traction and spin. With everything equal that will always be the wheel that spins.
@@ken9503 Hence, they had to be welded!!
Ken yep. On hard launching drag cars back in the day we would add a couple of spring rubbers on one side to counter the effect
It doesn't seem like assembly wouls be anywhere near as hard if you would jist use your 3rd and fourth hands.
In Australia we call 'em "Limmos" as in LSD's...
Not a job for a one armed paper hanger🤠👍
Scrap metal