AWD 4X4 pulls hard to Right HELP!!

[dgna5]

I have done literally Days of searching 10+Hrs. I can find many answers about a Brake or (end link ties etc.) cause of pulling on acceleration/braking BUT..
When I engage 4X4 ,(any mode AWD ,4-H, 4-L,). the truck immediately pulls hard to the right more like an intermediate Jerk, at any speed up to 25MPH'ish It Pulls, then I counter turn and seem when I hold the wheel to keep straight the act. steering wheel is turned about 30deg. to the left, like a bad alignment, All fluids are New frt./rear diffs, Xfer case, transmission, oil, .. good maintenance no Major abuse.
I have installed 3.73 in w/ Ford Racing limited slip in rear, Had to replace driver side Ball joint to get alignment right (Shoulda done both) replaced sway bar bushings with Red urethane also have EBS sloted/cross drilled with reman FOMOCO calipers. Ne who,
Truck Jerks/pulls when any 4X4 is engaged Please HELP!!

 

[flyin]

I would probably look at the right tube on the front axle. Maybe disconnect the engagement vacuum line and see if it still happens. Then disassembly would be in order. It should be obvious if it pulls that hard

 

[tonydiv]

What year is the truck?

Has any work been done to the front diff? Did you change the gears up front too?

 

[flyin]

97 expedition

 

[dgna5]

Yes '97 1st Nice rig tony flyin removed all 4tires (on lift) and ran thru 2wd small ringing noise like a slight sticking starter then put in AWD Major vibration frt. Right so shut down .next turned hub by hand driverside smooth as butter passenger side turns then "Lump" feels resistant but not bound? Feels like rolling a bent rod on a flat surface . But in 2wd no out right vibritation or noise at any speed? So idunno just take it all apart now. I have not changed gears up frt. Yet I was concidering a solid axle swap but found good IFS replacements (in a year or so!) Thank you guys

 

[Intraman09]

i gotta bump this. I have the same problem with my 2000 expy. Any chance this could be a front diff issue? Have you had a chance to pull it apart yet? Winter is comin and i really need to figure this out. I can't afford to just tear it apart unless i know what im replacing as this is my my only vehicle. Let me know what yall find, thanks!

 

[dgna5]

I have been on a road trip from hell replaced my 1-2 shift piston ON the Road!! Ne way I have not found any cause from outer axle,bearings etc. I am pulling Frt. Diff apart this weekend I will report and try to take pics,