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Rear end issue

Stoney

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Hopefully I can explain this in text...
My truck is a dually with a 4:10 rear end. Two wheel drive.. while trying to diagnose a noise complaint on the truck we had the rear end up in the air with the engine off.. truck was in park....
We spun the tires by hand so obviously the tires on the other side of the truck were spinning in the opposite direction as they should be..
They were spinning good, then they came to a dead-stop like something had grabbed a hold of them..I don't mean they slow down ,,,I mean they stopped instantly and bounced back the other direction a little bit... We got them spinning again and they did the same thing... We spun them the other direction and the same thing happened..
Keep in mind the noise complaint is coming from the rear end of the truck ,kind of a whining sound not sure how to describe it.. and sometimes the truck feels like something is holding it back or like you're hooked up to a really heavy trailer..
Just wondering if anybody has had any similar issues... Going to pull the inspection cover tomorrow and see if something broke in there again.. some of you remember it chewed up a pilot bearing on the end of the nose of the pinion a while back..
 

THEFERMANATOR

FRANKENBURBAN
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You most likely have a gov-loc in it. If so, that is exactly how they work. They work like an open diff until there is roughly 25 rpm difference between the 2 sides, then a flyweight engages a ramp plate, and locks both sides together solid via solid metal clutches. They stay locked until the tires spin the other direction or the vehicle reaches roughly 15-25 mph and another flyweight disengages everything.
 

Stoney

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So in other words if I were to be spinning the tires slowly it would never engage, it would keep spinning.... but then if I increased the speed past the threshold that you've mentioned it would lock up... I'm asking the way I am because if the way I just said that is correct it's an easy way for me to test the rear end I can spin at slow and maintain slow speed and see if it stays free spinning.... Then after I do that for say a minute... I could increase the speed and if it's working correctly it would reach the threshold and lock up..
Of course I still got to figure out what's causing the truck to drag
 

WarWagon

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Is this the truck with the wonky hydro-boost? If so I bet it's the brakes dragging from the hydro-boost problem not releasing the brakes.
 

Stoney

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I hope not...it's gonna be quite a while before I can fix the hydroboost..if it's making the brakes drag it's going to keep tearing up the truck worse....
 

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FRANKENBURBAN
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So in other words if I were to be spinning the tires slowly it would never engage, it would keep spinning.... but then if I increased the speed past the threshold that you've mentioned it would lock up... I'm asking the way I am because if the way I just said that is correct it's an easy way for me to test the rear end I can spin at slow and maintain slow speed and see if it stays free spinning.... Then after I do that for say a minute... I could increase the speed and if it's working correctly it would reach the threshold and lock up..
Of course I still got to figure out what's causing the truck to drag
Yes, below a certain speed it will not lock up, but the same holds true once you go over another speed.
 

RayMich

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A 25 RPM differential is not very much of a difference. That is the difference between the slow and fast wheel. That is 2.5 seconds per revolution. I bet it's going to lock up sooner than you think while one wheel is free spinning.
 
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