How a differential works - JeepForum.com

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post #1 of 23 Old 01-26-2011, 08:46 AM Thread Starter
TJ_Jerry
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How a differential works

This is the best explanation of how a differential works I have ever seen. And it is from the 1930's !

It has some cool motorcycle riding the first minute and a half but you can skip ahead to 1:45 and that is where the tutorial really begins.




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post #2 of 23 Old 01-26-2011, 08:59 AM
MO2500
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This has been posted many times but it does provide a good basic understanding of how an open differential works

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post #3 of 23 Old 01-26-2011, 09:08 AM
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It even includes LP vs. HP! Too bad it doesn't include the strength bonus from a HP30.

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post #4 of 23 Old 01-26-2011, 09:27 AM
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Nice video..love the old scoots too...
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post #5 of 23 Old 01-26-2011, 11:32 AM
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thanks for the post, this was the first time ive seen a complete description and it really cleared up my mind
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post #6 of 23 Old 01-26-2011, 11:51 AM
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Good explanation of a differential...I never knew that either. My uncle, who was one of the founding fathers of Mopar, tried to explain the concept of a differential to me one time and I had no clue what he was saying, but this really clears it up. Good vid!
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post #7 of 23 Old 01-26-2011, 12:21 PM
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Dang that really cleared up my confusion
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post #8 of 23 Old 01-26-2011, 02:00 PM
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awesome explanation of how spider gears work. That was the onlything i've never really figured out exactly how they worked on a diff.

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post #9 of 23 Old 01-26-2011, 02:16 PM
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I had an idea of how spiders worked but this makes it crystal clear now.

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post #10 of 23 Old 01-26-2011, 02:38 PM
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So HP is when the driveshaft is high on the differential(More driveshaft clearance), and LP is when it's lowered... less clearance...

Right?

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Hack work? :rofl: You just described half the modified jeeps on this board.
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post #11 of 23 Old 01-26-2011, 03:03 PM
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So HP is when the driveshaft is high on the differential(More driveshaft clearance), and LP is when it's lowered... less clearance...

Right?
Yes, basically. The pinion is above the centerline of the housing vs. being below it (which does raise the point where the driveshaft attaches, raising the driveshaft). The ring and pinion on a HP axle are reverse cut so that the pinion and ring gear mesh the same way at the top of the housing as they do in a LP axle. They are not "reverse rotation" as some incorrectly term them. Everything is rotating the same direction only cut differently which is why gears will not interchange between LP and HP axle housings.

A HP front axle is beneficial because the forces when in a forward gear are being placed on the "Drive side" of the ring and pinion gears which are designed to take the most load. With a LP axle, the forces in a forward gear are place on the "coast side" of the ring and pinion. This can cause more housing deflection and eventually gear failure if pushed too hard because the gears are actually trying to push each other apart due to the more angled faces of the gears.

A high pinion axle is strongest in the front and a low pinion axle is strongest in the rear. Keep in mind that this is when moving forward.

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post #12 of 23 Old 01-26-2011, 07:05 PM
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Excellent, now it makes sense!

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Hack work? :rofl: You just described half the modified jeeps on this board.
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post #13 of 23 Old 01-27-2011, 07:16 AM
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Great video. Took me from "no idea how it works" to "that makes sense".
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post #14 of 23 Old 01-27-2011, 09:42 AM Thread Starter
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Originally Posted by Whybu1 View Post
Great video. Took me from "no idea how it works" to "that makes sense".
It's and eye opener !!

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post #15 of 23 Old 01-27-2011, 10:20 AM
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Quote:
Originally Posted by MO2500 View Post
Yes, basically. The pinion is above the centerline of the housing vs. being below it (which does raise the point where the driveshaft attaches, raising the driveshaft). The ring and pinion on a HP axle are reverse cut so that the pinion and ring gear mesh the same way at the top of the housing as they do in a LP axle. They are not "reverse rotation" as some incorrectly term them. Everything is rotating the same direction only cut differently which is why gears will not interchange between LP and HP axle housings.
I have a question. Can you mesh a pinion gear into a reverse cut ring gear without reversing the rotational direction the gear teeth spiral around the pinion gear head?

Can you think of a way to run a low pinion gear set in a high pinion application and still run hypoid gears?

Quote:
A HP front axle is beneficial because the forces when in a forward gear are being placed on the "Drive side" of the ring and pinion gears which are designed to take the most load. With a LP axle, the forces in a forward gear are place on the "coast side" of the ring and pinion. This can cause more housing deflection and eventually gear failure if pushed too hard because the gears are actually trying to push each other apart due to the more angled faces of the gears.
What distinguishes the drive from the coast side on a ring gear?

Quote:
A high pinion axle is strongest in the front and a low pinion axle is strongest in the rear. Keep in mind that this is when moving forward.

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