Truck lurches when in 4x4

[Ford110]

I've got a 67 f100 4x4. When engaged and under load(pulling a trailer uphill) it occasioanly seems to lurch, or disengage then engage again, almost like a gear is skipping. Transfer case seems a bit notchy going in, like the fork is not fully engaging. If the transfer case was popping out, I dont think it would engage again cleanly(no grinding, et). Drivetrain? Hubs?

[BRUTUS_T_HOG]

if its a divorced transfer case is it most likely worn transfer case mounting bushings, the transfer case is allowed to rock around under load and cause the driveline to bind.

Also if you are driving in 4 wheel drive on hard surfaces with plenty of traction it is normal for the drivelines to bind and fight each other. Only use 4 wheel drive in low traction conditions or you could destroy the transfer case, break a hub, or snap an axle.

[CrypticRacer13]

I agree with Hog, also check your linkage out and make sure everything is set right. but it dose sound like your bushings could be the problem.

[Ford110]

bit more info. The transfer case is married, and its happening pulling a snowmobile trailer up snow covered mountain roads, so i don't think there is an issue with the wheels fighting each other, et. There is a fair amount of slippage.

[Doug Comer]

Gear ratios the same front and rear?

[1970 Hi-Boy]

Do you have a traction lock rear end? If so, is it possible you're feeling it engage/disengage, when one wheel begins to slip?

[Ford110]

stock drive-train(4.10), dana locker in the back, manual transmission.

Happens about every 2 miles, didn't notice that it was on corners, but could be on gradual corners , does not happen on sharp corners

no grinding, seems to skip and pop right back in. Quick clutch slip? I would think it would start slipping i would hear engine rev

[1970 Hi-Boy]

Your still geared to the road the clutch is between the two wheels, so no engine revs. Try adding a tube of anti-slip additive(you can get it from Ford or anywhere that sells oil), you may want to change axle fluid for some fresh 80W-90 as well if it's been a while. That should allow your clutches to work without noticing the "chatter".

[BRUTUS_T_HOG]

stock drive-train(4.10), dana locker in the back, manual transmission.

Happens about every 2 miles, didn't notice that it was on corners, but could be on gradual corners , does not happen on sharp corners

no grinding, seems to skip and pop right back in. Quick clutch slip? I would think it would start slipping i would hear engine rev

if it doesnt do it in 2wd then i'd suspect normal wheel slip due to the 4wd not allowing the wheels to turn at different speeds.

when you say skip do you mean there is a loss of power to the wheels and the truck bucks? is the engine revving at all during this like is has actually come disconnected from the drivetrain?

[Ford110]

Yes, I would say a breif engine rev as it bucks, like a short disconnect between the engine and drivetrain, then back to normal