PSA Choose A Good Gear Installer

mtnbiker4evr13

mtnbiker4evr13

Trail Whale
Joined
Sep 18, 2018
Location
Asheville NC
When my 4runner was originally built in with a pair of low pinion E-lockers I had a "friend" at a local transmission shop in Ohio setup the 5.29s in them. Roached the original rear setup climbing a waterfall so I set the replacement up myself and put the old "professional" setup in the rear since it should be better right?..

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I'm impressed they lasted ass long as they did. Wear pattern on the ring shows its heavy on the heel with heat discoloration to match, Pinion has wear on the outer end of the gear also showing a shallow setup. 35s, dual cases and a 4400lb rig will do that I suppose, I would have chalked it up to wheeling consumables/shock loading until I looked at the wear pattern and heat marks. Time for fresh gears/bearings and a proper setup.

Thought some would get a kick out of the post mortem autopsy.
 
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Trying to follow, so you moved your "professional" front 3rd to the rear? An LP front runs on the coast side of the gear under power. Could there be possible issues with having moved it to the rear? I hear you on the pattern but the gears were applied differently after they were moved, the stress on the tooth is not the same. Clearly, a centered pattern is best all around.
 
OnlyOneDR said:
Trying to follow, so you moved your "professional" front 3rd to the rear? An LP front runs on the coast side of the gear under power. Could there be possible issues with having moved it to the rear? I hear you on the pattern but the gears were applied differently after they were moved, the stress on the tooth is not the same. Clearly, a centered pattern is best all around.
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Yep that was several years ago. I don't think I've ever heard of that being a problem switching a front to rear application. It would probably be less broken in on the new drive sides of the gears initially... hmm... never really paid it much thought after short changing the diff oil the first several hundred miles.

I'm open to the idea, but evidence of poor setup is more of a smoking gun.
 
Ron said:
I'm in to learn.
Can you provide your input into the above discussion regarding front vs rear
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I see no issues moving a third from front to back as long as the pattern was acceptable. True a LP front drives on the coast side, so that side would have more wear that compared to the drive side. But when swapped to the rear, it would then be driving on the drive side (which would have very little wear in a front application).
I say whoever setup the diff botched it.
 
There is a strength difference between the coast side and drive side, but I'd guess it's in the neighborhood of 10%, not anything significant in a normal application. How often do people bust diffs backing up?
 
Jody Treadway said:
I see no issues moving a third from front to back as long as the pattern was acceptable. True a LP front drives on the coast side, so that side would have more wear that compared to the drive side. But when swapped to the rear, it would then be driving on the drive side (which would have very little wear in a front application).
I say whoever setup the diff botched it.
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So here's a question....Note I'm in no way familiar with Toyota axles other than, "yup, that a yota axle". I know on LP D60 fronts, the casting is different than a rear LP D60 since the ring gears are spinning in opposite directions. Because they are spinning in opposite directions, oil is slung differently and therefore there are different oil passages to the pinion bearings. Would these Toyota 3rd members be the same casting or would they have differences for front/rear applications?
 
adamk said:
So here's a question....Note I'm in no way familiar with Toyota axles other than, "yup, that a yota axle". I know on LP D60 fronts, the casting is different than a rear LP D60 since the ring gears are spinning in opposite directions. Because they are spinning in opposite directions, oil is slung differently and therefore there are different oil passages to the pinion bearings. Would these Toyota 3rd members be the same casting or would they have differences for front/rear applications?
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The gears still spin the same direction, forward for forward movement, backwards for reverse movement. The difference is which side of the tooth the power is applied to. The internal castings and oil galleries are the same for all intents and purposes. The use of slingers in a front diff application is what the difference is. In the front the slinger keeps oil at the inner bearing longer since the oilis not being slung into the upper gallery like in the rear. The slinger keeps the oil on the inner bearing longer by slowing down the rate at which it drains away.
 
Jody Treadway said:
The gears still spin the same direction, forward for forward movement, backwards for reverse movement. The difference is which side of the tooth the power is applied to. The internal castings and oil galleries are the same for all intents and purposes. The use of slingers in a front diff application is what the difference is. In the front the slinger keeps oil at the inner bearing longer since the oilis not being slung into the upper gallery like in the rear. The slinger keeps the oil on the inner bearing longer by slowing down the rate at which it drains away.
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learn something new every day. Thanks man
 
Jody Treadway said:
I see no issues moving a third from front to back as long as the pattern was acceptable. True a LP front drives on the coast side, so that side would have more wear that compared to the drive side. But when swapped to the rear, it would then be driving on the drive side (which would have very little wear in a front application).
I say whoever setup the diff botched it.
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Along these same lines, would it ever make any sense to swap F&R from a wear perspective? I wouldn't think the wear on a R&P would be considered "normal wear & tear" and prolong the life but curious if it ever makes sense to do nonetheless (Toyota low pinion e-lockers F&R for reference).
 
rcalexander105 said:
Along these same lines, would it ever make any sense to swap F&R from a wear perspective? I wouldn't think the wear on a R&P would be considered "normal wear & tear" and prolong the life but curious if it ever makes sense to do nonetheless (Toyota low pinion e-lockers F&R for reference).
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If you ever have enough wear for it to matter, then either something else is wrong, or you got your money's worth. A half million mile gearset should look like a smooth, slick version of a new one if setup properly. Also, since your contact patch is a curved surface in the center of the teeth, as it wears, the surface area and load distribution actually increase, which in effect decreases the wear rate because the load is spread over a larger area. But we are talking 4th and 5th decimal of an inch kind if stuff. If you see wear, beware.
 
jeepinmatt said:
If you ever have enough wear for it to matter, then either something else is wrong, or you got your money's worth. A half million mile gearset should look like a smooth, slick version of a new one if setup properly. Also, since your contact patch is a curved surface in the center of the teeth, as it wears, the surface area and load distribution actually increase, which in effect decreases the wear rate because the load is spread over a larger area. But we are talking 4th and 5th decimal of an inch kind if stuff. If you see wear, beware.
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I didn't think it'd matter or make sense but the thought crossed my mind doooo figured if throw it out there
 
<---I got a junk yard lp front dif. for this truck when the OEM exploded going 50 mph, hell of a ride till I stopped.I put the front diff. in the rear and ran it for 6/7 years as a DD w 33's. Then I pulled it out to put a Randys 5.29 dif, in the rear ( was gonna get 35's and a 5.29 in the front). Changed my mind after a few/4 yrs and sold the 5.29 and put the front diff back in the rear.
 
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