I believe you're on the right track about the rear diff. Because when I turn when its acting up theres kind of a slight vibration sometimes. I hav'nt been able to pin point where it comes from yet.

 

If you remove the rear shaft and drive around in front wheel drive the rear end would not really be in play then. You could prove your idea. I'm thinking its in the fuel system. Or in your head.

 

Could you have two deferent gear ratios and don't know it. Just saying

 

That would only happen if he was using 4wd. He said he wasn't as it was at highway speeds.

Remove the rear driveshaft. With hardly any weight and stock skinnys aired up to 80lbs, if it binds, you will hear the tires protest.

Posted via Velocity LG ALLY

 

ooops

 

I'll remove the drive shaft soon. How fast should I drive with it off? <40mph?

 

Got to thinking, I think the only way to eliminate the rear axle from the list of possibilities would be to install a different one that does'nt have problems. With the drive shaft off the axles would still spin and internals would all move still. Only difference would be that there would'nt be torque on the pinion, but that should'nt matter in this case.


"Well should be gear oil but if it were there before..."

I know there are mixed opinions about what fluid to use in the transmission and t-case, I'm not saying that engine oil is better than gear oil by any means. My manual says its ok to use specific weights of engine oil, the fact that there is oil and at the correct level is the thing here.

 

I have a fairly heavy bed on the truck but am running the stock size tires. So, on the dirt road I need to check to see if the rear tires try to skid? I'll give it a try.

 

You could pull the rear driveshaft, and the rear axles, covering the hubs with a plate to keep in the oil and keep out dirt. Also gives you a chance to spin the wheels without drag and make sure brakes and wheel bearings are OK.

The wheels will stay on without the axles.

Don't know what kind of transfer case you have, but when chains or gears get worn, sometimes they will climb on each other and bind like crazy, especially under load, then let go when the load comes off.

 

If you can, the next time you experience the problem, get the rearend off the ground and try to rotate the rear wheels by hand. If the problem is there I'm betting you won't be able to budge the wheels.

 

When ever the problem is goin on its with load and no load, because it dont coast as well even in neutral.

T-case is a np205

Yea, wheels should be hard to turn if it pulls the cummins down a bit

 

If you get lucky enough to be at home the next time it acts up, once you get the rears up and try turning the wheels if it's hard to turn, drop the rear drive shaft. If that frees up the wheels lower the rear, leave the shaft out and move to the front and repeat. If the front turns free you now have the axles eliminated.

 

Has anyone found an answer to this? My 93 in sig. exhibits the same symptons and I've check/replaced a number of items. Just seems to be holding back somehow. I can be cruising at 30 or so and when I let off the pedal, it seems to actually coast better like it's being released or something?

D

 

to be honest, it wouldn't surprise me if it was something like a torque converter degrading over time.

 

These are possibilities and it all depends on if you have factory exhaust and intake. The first is the rubber intake pipe collapsing in causing a intake restriction which in turn causes engine shutter black smoke and other goofy stuff, you let off the throttle air flow demand drops the pipe returns to normal engine runs good. The other is a plugged muffler, broken baffle flopping around causing a restriction. just some thoughts I have seen it happen.