96 5.0 AWD Won't move

[jar2187]

I just got a 96 limited with the 5.0. It is all wheel drive. It has 115,000 miles on it. Before we got it, it wouldn't move so they disconnected the rear drive shaft, and it moved from there. My dads tow truck driver drove it onto the flat bed with. Mind you just the front wheels where pulling the truck. Well the rear end is now locked, and the tires dont turn. The front wheels will no longer pull the truck either. What do you guys think could be wrong.

 

[Four0Sport]

your rear end is locked up, thats prbly what is wrong.. and the added strain on the front diff isnt helping much.

 

[jar2187]

so do u think anyhting happened to the front end. Because it moved before and then all of a sudden stopped, and the rear end locked up.

 

[V8Exploder]

sounds weird. Maybe some teeth broke off in the diff and locked up the ring and pinion.... $sound$ like trouble$$$$.....

 

[Fusion213]

Pop the cover and check it out.

 

[jar2187]

Thats what we plan on doing. I just hope its not the transmission.

 

[jar2187]

My dad said that, when u put it into drive now and give it gas it doesnt even make and effort to move, and before it did.

 

[CDW6212R]

Do you mean the rearend? Lift the back, do the wheels spin freely then?
DW

 

[jar2187]

Yes i mean the rear end, there is no rear drive shaft connecting the rear end. So the lock up is somewhere in the differental.

 

[jar2187]

I opened the differental and, the ring gear had missing teeth on it, the carrior for the spider gears was ripped up. and so was a spider gear. I found the rollers from one of the bearings, I am not sure which one it is yet. We believe that it was from either shock or, that one of the bearings went bad and thats what caused the gears to loose their teeth. I shoke the front drive shaft and there was no play in it, so I take it that, its a good sign. I am hoping the the rear end just locked up and thats why it wont move now. Would the front end have enough power to pull the locked rear wheels? If so it would cause damage to the transfer case, correct?

 

[V8BoatBuilder]

Inside the AWD t-case, the rear driveshaft output is directly connected to the front input (the transmission). The front shaft is turned by a chain off of this mainshaft, and then through a viscous coupler allowing slip.

If the rear differential was 100% locked up, then the truck would not move because the entire drivetrain would be locked up. When you pressed the accellerator, the torque converter absorved all of the energy. It's the same as if you gassed it with the brakes full on. So, to answer your question, in your case, the front wheels would NOT receive any power to pull the truck.

You might want to remove the rear drivehsaft, then jack up the front end and put the truck in drive. If everything is OK, the front wheels should spin, and so should the coupling flange on the back of the t-case.

 

[jar2187]

Even with the rear drive shaft removed, should it try to move?

 

[V8BoatBuilder]

Yes/No/Possibly. Let me explain.

As I explained earlier, the transfer case has a solid linkage between its input and the output to the rear shaft. The front shaft is driven via a chain and a viscous coupler. If the rear is locked up, the whole thing is locked up. If the rear is free, and the front is free, then they should spin at the same rate. However, since the connection to the front shaft is fluid-based (the viscous coupler), if the rear is 100% free, such as no driveshaft attached, but the front has a load on it (the weight of your truck), then it may or may not receive power. If you apply enough spin, (press the gas), then the viscous vanes in the VC with cause the fluid to thicken and turn the front shaft. That's also how the AWD works in the BW4404 case: if one axle is spinning faster than the other one, the fluid thickens and a connection is made.

So - bottom line - like an open differential, the power goes to the path of least resistance - but always to the rear wheels. With the rear driveshaft removed, most of the power applied will just spin the output flange. If you take the weight of the truck off the front wheels, then they should turn.

 

[jar2187]

Does anyone think anything else is broken? Like the transmission or the transfer case.

 

[V8BoatBuilder]

Well there is a chance that the continued application of force with the rear locked up broke something inside the t-case or transmission. Like i said, remove the front driveshaft or jack up the front, put the truck in R and D and observe the t-case flanges, and listen for noise.

Fix the rear end, then you'll know for sure when you re-attach the rear driveshaft.

 

[jar2187]

Update: I picked up a used rear end from a junk yard for $150 and, my dad and I replaced it yestreday. With the rear drive shaft reconnected and all four wheels off the ground I put it into drive and only the rear wheels moved. Is this supposed to happen with AWD?

 

[CDW6212R]

No, is the front driveshaft still moveable by hand, up in the air? Sounds odd.
DW

 

[jar2187]

when you turn one of the front wheels, only one of them moves and the front drive shaft doesnt move, but if you hold the other wheel the drive shaft moves. You can turn the drive shaft by hand.