I checked out all the vacuum lines, and everything checked out. Transfer case shifts, and vacuum operation appears to work on hubs. I lifted the front of the truck and did the following:

[quote other forum]Put the front end on jack-stands. With it off the ground lock the hubs and have someone
hold one tire and turn the other one the driveshaft should turn. Then reach under and
hand turn the driveshaft the wheel should turn. Swap sides and the other wheel should
turn. put it into 4 H try to turn drive shaft. It should not turn. Hold one tire/wheel and
try to turn the other one you should not be able to. Let the one wheel go and turn
the other one. Both should turn while they ar turning listen for any clunking.
If you get clunking while doing that you most likely have a bad spider gear set.
I found this photo of the gear sets[/quote]

With the hubs manually locked, truck not in 4WD turning a wheel did nothing to the opposite side wheel or drive shaft. Placing the truck in 4WD high same results, when I turn one of the wheels nothing happens to the other wheel or the drive shaft.

Are my hubs jacked? Front differential?

Any ideas appreciated,

Keith

 

Im thinking differential. Pull the cover off and see whats in there.

 

Ditto.

You don't have to lift the truck to check the hubs. I grab my drive shaft in 2HI and roll it. If a hub is hanging up in the AUTO position (which mine have due to needing lubed), it will act like it's in 4HI. I had to stick a screw driver in the u-joint to hold the passenger side and wiggle shaft while I monkied with driver side hub. It finally unlocked.

If you're weight off wheels with hubs locked and one tire doesn't turn the other, pop the diff cover and see why not. At a minimum the other should counter rotate.

 

I assume I need a drain pan, gasket, proper sized socket, and new fluid.

What fluid and gasket, are they "local parts store" items or "get if from Ford" items?

I will pop the cover as soon as I have the gasket and fluid.

Thanks,

Keith

<edit>

Never mind, looks like I need Permatex Black Hi-Temp RTV sealant and 5.7 pints of 75W-90 synthetic gear oil.

Any particular brand of gear oil? Royal Purple?

</edit>

 

I used heavy conventional gear oil (forgot grade, 140 maybe) in the Dana 60 in my 1/2 ton. That took about 3 quarts. Wait til the RTV starts to set up, gooey RTV will go everywhere when you tighten up the diff cover.