The carrier bearing is the there to keep the longer driveshaft straight. If its worn or broken it could be letting the driveshaft run with a bend causing a bind.

 

The nut that holds the rear yoke seemed loose. I tightened it and will see if that helps. I hav'nt had a chance to check the rest yet though.

 

Seemed loose? I thought those were supposed to have a few hundred ft-lbs of torque on them. Yikes.

 

Yea lol, 250-300ftlb is what the book says. I'll check it in a week or so. If it is loose again I'll put some blue locktite on it.

 

I would suggest getting a new nut, as they are supposed to be one time use. I'm not throwing stones, because I've used them again, but I replace them the second time they have been used. I suppose locktite would work, don't see why it wouldn't, but I'd be conserned if it had a chance to booger up the threads of the pinion, if/when you need to remove it again.
Back on topic though, I don't see how that would cause the problem you are having, unless it was really loose and was allowing the pinion go into the ring gear. And if that is happening then I'd think you would have more problems then just a loose nut. Can you move the yoke at all, meaning in and out play or side to side?

 

Ok, I'll definatly consider buying a new nut if I take it off again or keep having trouble with it loosening.
There is play if I turn it back and forth, the yoke fits to the splines tight but there is a fair amount of internal play it seems like. I did'nt notice any in and out play.

 

"Back and forth" play is ok, you are feeling the backlash when doing that plus side gear to axle clearances.

 

I know for certain that the clutches inside the rear are worn and there is a clunk somethimesat low speeds while turning sharp and when I push the clutch pedal. Looked like the rest of the gears were fairly worn too.

Could anything inside the rear cause a "dragging" feeling? It feels like there is always a large trailer hooked up, except sometimes. Like I said its had this problem for atleast a couple years now. I would have figured something would have torn up by now

 

Ok, thanks for the info

 

I'd think there is something you aren't think of. Maybe something in the fuel system? Is there anything else that happens when you feel this, like smoke, shudder, surging, things like that?

 

I actually thought it might be a fuel problem at first, but I cant find nothing wrong.

When the problem goes on there is more (dark) smoke during acceleration, boost during normal driving is slightly higher and egt's are higher. When its not throwing a fit the smoke is fairly controllable.

Here's the thing, when I push the clutch the truck slows down faster than normal and does'nt coast in neutral as well.

During acceleration, you know what it feels like when you start from a stop at the bottom of a hill and you loose a bit of speed between shifts with a manual trans? That's what it feels like to me. Just like the brakes are dragging a bit or something.

 

There's a good chance the pinion bearing is toast, especially if there's metal shavings floating around in there. I would also be concerned about the carrier and wheel bearings as well. Caution calls for a thorough inspection followed by disassembly and cleaning and possible replacement of all the bearings in the rear.

 

Actually, if it's been binding like that, and there's metal in the lube, I'd be looking for a new gear set, cause that one is spalling and will totally fail in short order.

Once hypoid gears have made metal to metal contact, it's only a matter of time (usually not much) till there's nothing left.

I'm old enough and rough enough to have shelled out a dozen of em over the years.

 

Yea theres some clutch material in the diff fluid. I have a d80 I'v been slowly working to replace the 70 with. I guess I'd better get it ready soon lol. I'd hate to ruin the thing completly.

Have you had a differential do this before? As in where it makes the truck feel as if the brakes are hanging and it not get hot?

 

What yer describing is usually what you feel when you have different sized tires on the front and rear. The numbers don't have to be different, just the wear in em.

I have cracked a cover bumping junk in the woods, and subsequently run it out of lube. I've crashed many on larger trucks pulling real hard (as in pulling logs) back when it was a lot easier to film crash the lube. They get noisier and stickier till they stick tight.

Usually when you feel gears binding, they're done for.