front diff 4wd broken??

[melmount]

Let me start by saying new transfer case and front driveshaft.
I installed manuallocking hubs and plugged off the vacuume lines for the esof hubs.
I(hubs unlocked) switch the dash to 4wd hi, then continue to drive. No issues all is smooth. I then get out and lock one hub, again, all is fine. I unlock that hub and lock the other one,(test driving, with only one hub locked at a time) all is still fine. Now, I lock both, Very unsmooth. Something is broke. Truck is bouncing, really screwed up.
Please dont say its the 4wd on dryground. I am going straight only. I also did this withmy wifes f350 4wd dually and its fine and smooth. A little more aggressive feeling in 4wd but nothing is broke.
Mine is broke. I tried tightening the pinion nut a bit but the shaft binds if i do. Theres a little play in the shaft.
I am trying to figure out whats moving when both hubs are engaged and whats not with only one. When onlyone hub is locked its driveable. Both hubs its not. even going straight. It will still drive but gives the feeling i am going to really break something.
spider gears??

[dieseldan2005]

I am just wondering, when you left the hubs unlocked and hit the switch were you stopped or moving? Cause when they are unlocked and you hit the switch mine would grind like a s.o.a.b! This cause the hubs being unlocked so the driveshaft wasn't turning then slam the t-case into gear and she doesn't like that. Does your noise sound like front diff or still in the t-case. I had an f150 that the chain the t-case would bind from no use and it would literally stop the truck from moving in reverse. Then going forward it would hop and bounce big time only going about 5mph. It would do this until you went back and fourth to release the stuck chain. Just wondering if the chain inside the case is out of adjustment?

[melmount]

the transfer case is not the issue. I am positive of that. I can shift on eht ly or stop. Its quiet. I have to stop for 4 low.(of course)
With one hub locked, shifting stopped or moving all is fine. Lock both of them. Then drive its auwful. Big vibrations at 5 mph. I am trying to getan idea of what can go wrong with these dana 60 front diff's?

[melmount]

again, I only feel the issue if both hubs are locked..

[dieseldan2005]

I just find it weird that it doesn't grind when the hubs are unlocked while moving, if you understand my point. When the main driveshaft is turning in the t-case and you hit the front driver they aren't sync'd up and the front will grind like hell in the t-case until you come to a stop and she falls into place. What was your original reason for replacing the t-case and hubs?

[melmount]

the transfer case caused a clunk in reverse to drive or when coming to a stop. I was not sure what it was, but i went for it,(the swap) and the transfer case fixed my noises. I changed the front esof hubs to warn hubs.
My wifes truck wont grind when going to 4wd while moving either. Makes no difference whether hubs are locked or not. 4wd low it will, have to be stopped for that.
I dont see why having the hubs locked or unlocked would or would not cause a grinding sound. That would only grind if something in the t-case was going south.

[dieseldan2005]

Weird, both of my last trucks did that. One was a manual t-case with ford manual hubs, and the other was an esof with warn hubs. They would grind because with manual hubs the front drive shaft won't turn until either it gets power off the t-case or is turned by rotation from the hubs being locked in. But when you are moving and flip the t-case into 4x the front driver isn't sync'd up and grinds until you slow down and it falls into place. Anyways yeah maybe there is a stripped gear in the front diff then. I wouldn't know what else it could be. Have you changed the fluid p front to see if there are any metal shavings in it?

[melmount]

yeah, just did a fluid change. No chunks or anything. But the fluid was shiny metal in color. Like you put metal thru a blender and mixed it with the oil. I know when i tightened the pinion nut, to try and take out pinion shaft play, it would bind and stop at the same spot in its revelution. I have a feeling its in the front pinion bearings.
You would think with esof hubs when you shift to 4wd the t-case will shift into 4wdand lock the front driveshaft into play long before the vacuume pulls the hubs locked. There fore doing pretty much what i am doing. Locking the t-case then getting out and hitting the hubs. My old transfer case did not grind into 4wd either. Hopefully someone will have a clue on the front diff. I think, maybe, with both hubs locked, its putting more force to the pinion and pinion gear. This would put pressure(twice as much as one hub only locked) on the pinion bearings.From my past experiencesif you overtighten a pinion nut it will wear the bearings out. But the pressure should be even all the way around the bearing. Not just bind in one spot in its turn, then be loose for 3/4 of a turn. If i in fact could over tighten it by a lot I should feel constant tightness thru the whole turn of the yoke??? Right?

[melmount]

Are their syncros in a t-case? If so and if they are good, that would be why I have no grinding??

[Degnol]

With an open diff in front and only one hub locked, you aren't really in 4WD, but with both locked, you are driving one of the axles, that puts a strain on all the moving parts and may make something show up that would not with no load on it. Check the front output shaft/bearing on the TC and as you mentioned, check the pinion nut. A lack of adequate spline engagement can cause a nasty vibration, too. Is the truck lifted?
GL

EDIT: Is your driveshaft in phase? Are the yokes lined up? If not, that can cause wierdness and vibrations, too.