Got a 96' F350 crew 4x4 gasser towpig.

In 4wd, manual hubs locked, 4wd will function, but feels lurchy. :homer:

Naturally it's worse when turning, but even with the front end straight, it feels like it's loading up, then un-loading as it rolls.

over and over. I keep waiting to hear something snap.

Noob> Am I looking at u-joints in the axle, the front driveshaft, something else?

Functions every time, really lurches though.

The truck has 150k, everything I've changed has been original.

4th owner.

Thanks for any help.

Maybe are the gear ratios different? You said it was loading and then unloading and lurching, sounds like that might be your troubles to me

X2^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

should roll smooth forward...lurching/bining in a straight line isn't a good sign. tire sizes all teh same?

Tire sizes are all the same, new 235/85's or something like that.

I'll have to start checking tags then.....

Anyone have the info for deciphering the codes from VIN's, I could pull that, and the axle tags, see what I have there.

Thanks for the replies.

Were you on asphalt during these tests? Never run 4WD on asphalt. Equal tire pressure front and rear?

VIN won't tell you anything. And the axle tags might give you a clue....but who's to say the previous owner didn't change the gear ratio in one axle and not the other?

Only sure fire way to find out would be to remove the cover and count teeth, or spin the DS and count revolutions.

4wd tends to feel like it binds on the street, the gear ratios are different enough (like 4.09 to 4:11) that the difference needs to go somewhere. and that is the felt bind.
If your ratios were very different, like 3:50 and 4:11 you would only drive about 100 feet until something blew up.

Thanks for the replys guys.

This was in the grass, on my property dumping a parts Jeep on the rear of the lot.

I haven't had the need much to have it in 4wd. Every time it's been used though, it's been on the grass.

Driven for more than 100 feet, and under load to boot in 4wd, several times as I've been bringing in some parts rigs the last few weeks.

Back yard is wet alot.

Thanks for the replys.

Looks like a cover pulling is in my future.

alot of Ford ujoints dont lube like they should...had 06 F350 CC 4x4 in our shop that did that, my boss's 04 F-150 CC 4x4 did that...both turned out to be bad ujoints...the best fix is new ujoints with grease zerts drilled and tapped into all four bearing caps, not only does it make it easier to get to the zert, you KNOW all 4 caps are getting grease..id check that first, its cheaper, and even if its not the problem you now have spiffy new ujoints....but by all means be sure your axle gears are right, somebody may have cheaped out and only replaced the rear to get better towing................have someone watch the wheels while you drive in the grass, they may be able to tell if the axles are spinning differently...

u joints