Front Diff Question...

[KRAZIE87K5]

Hubs are locked. Drivers front wheel jacked up. Passenger front on the ground. No drive shaft connected (because there is no drivetrain in the truck). When I turn the rotor and assy., I hear things inside turning, but the pinion does not turn. I see the axle heading into the housing is turning. I think I may hear some sounds from the carrier. BUT THE PINION IS NOT TURNING!!!! Please someone tell me that my diff is not busted.

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[ftn96]

Sounds like and open differential to me. Try and turn the pinion and see if the rotor turns. Also jack up both sides and turn the rotors and see if the pinion turns and again turn the pinion and see if the rotors turn. With an open diff and one tire on the ground this may be causing it not to turn like you would expect.
Also just take the cover off adn see if anything is broken. Chances are you need to change the fluid anyway.

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[ftn96]

With open diff's theres not much to go wrong in there other than the spider gears being chewed up other than that. Theres nothing else in there to mess up as far as this is concerned.
But your pinion bearing could be seized up somehow. Is this truck new to you and didn't have a front driveshaft in it when you got it?
But I have never seen a pinion bearing seize up before. But thats not saying that it cant happen.

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[6.2Blazer]

It sounds like something is definitely wrong.

If BOTH hubs are locked, one tire is firmly planted on the ground and the other up in the air.....if you spin the tire in the air the driveshaft/pinion should turn.

Here's what I would look at.
Locking hubs - since you can see the drivers side axleshaft spinning then that hub should be okay, however I would also check the other (passenger side) hub to make sure it is engaging. If both hubs check out okay, then it's something inside the diff. Pull the cover and take a look. If the spider or side gears are chewed up enough to not let the axleshaft engage the diff, then it should be pretty obvious.

 

[BurbinOR]

Heck, try turning the pinion input, then you'll see the rotors moving............my D60 in the yard does that. One wheel was bound up with rust (the rotor was), and nothing turned..........nothing wrong with it now!

<font color=orange>'79 - 406 TPI -<font color=orange> K5#5 - <font color=blue>See it at---&gt;<A target="_blank" HREF=http://www.blazzinor.coloradok5.com>http://www.blazzinor.coloradok5.com</A>

 

[KRAZIE87K5]

I agree, that something is wrong. I have tried turning the pinion and the rotor in the air does nothing. Second - I have shattered a few spider gears in my day. There is no appropiate grinding noise coming from the diff. The hub is operating correctly, because the axle is turning behind the rotor when I turn it. As for the passenger tire, I will have to jack up the other side and see what happens when I turn that tire.

But the part that bothers me is that, I know the diff is open. Therefore the power SHOULD travel to the path of least resistance. But when I turn the pinion, in either direction, the "power" seems to go nowhere, and the rotor (which can spin and is NOT locked with rust or anything) just sits there and laughs at me. WHY??? Please dear God, won't my truck stop tormenting me???

Also, as a side note... How was I blessed with a corporate 10 bolt with 8 lugs? Was this axle converted somewhere along its life? And no, the truck never has a drivetrain installed since I bought it!!!

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[dyeager535]

Could it be that the hubs are shot? When you spin the rotors with the hubs locked, the axleshafts DO turn? If both axleshafts can turn, but the pinion doesn't move, then it HAS to be in the diff carrier right? Popping the cover off isn't a big deal anyway...

And I have to assume that the later 3/4 tons just used a 10 bolt with the 8 lug hubs etc bolted on them, so that would be the origina of those I bet.

Dorian
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[BadDog]

I think either the diff is broken or, I think more likely, you have snapped an axle shaft clean at the inner spline or a stripped hub on the side which is on the ground. Only way you will know is to pop the cover and see where it stops turning.

Bad Dog

85 K30 CUCV, 350 TBI, TH400, NP205, D60/C14, 4.56
Coming soon: 4" lift, 40" tires, massive cutting, shorter wb and rear overhang.

 

[ftn96]

It sounds to me like there are no spider gears in there. Or the teeth on the pinion gear are just plain gone. Or maybe there is no ring gear. Cause if you are turning the pinion something should turn unless there is something missing, IE the pinion teeth are not contacting anything.
You just need to take the cover off. Thats the only way you can tell. Turning listening and guessing will get you nowhere.
Sounds like there is ni ring gear or the are no spider gears.

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[KRAZIE87K5]

OK it works. I got back home, unlocked and then re-locked both hubs. Then I turned the rotor and the pinion turned, thank god. Anyhow, could that imply that one of my hubs is begining to fail???

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[tRustyK5]

I had something similar happen with my hubs. The grease was just old and gooey and prevented smooth engagement. I cleaned and regreased the hubs and presto! Now I do them regularly.

Rene

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[ftn96]

That is good news. DO like trusty said, take them out and clean them up and re-grease them with some new grease. New grease is always good.

Will work for beer, parts and tools.
90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
<A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>

 

[BadDog]

Hmm, never had that happen. I've had mine get bad enough that I couldn't engage them, but it was because I could no longer turn the dial

. Never seen one that turns to full engaged but is not locked, maybe I just never noticed...

Bad Dog

85 K30 CUCV, 350 TBI, TH400, NP205, D60/C14, 4.56 Locked
Soon: 4" lift, 40" tires, massive cutting, shorter wb and rear overhang.

 

[OFFRDK5]

Just for information. If you have an open front end...
Tcase is in 4hi
hubs locked
both fronts off the ground...what should turn?
Reason I am asking is cuz I did this and only the other tire turned...I thought the front shaft should turn too?
Thanks


SK-15
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[dyeager535]

With your description, the driveshaft should rotate, as well as ONE wheel. Not sure if the other wheel rotates the opposite direction or not, but I believe yes if neither tire has any drag.

Dorian
My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>