AWD not biting

[J10rules]

I have a 1981 J10 and i have noticed recently while working down in the woods that the front tires are not biting like they should be, and sometimes not even turning at all causing the rear wheels to just spin out. My transfercase is a np219. I was wondering maybe what would be causing this or maybe its just because its so old something went out. How could i diagnose or check this out. thanks

[Ryan]

edit: this applies to an NP229 case, and NOT a 219 (misread original post):
It's possible you have a vacuum problem or the diaphragm on the tcase is leaking. Also, make sure to check the fluid. Remove the large +/- 1-1/8" bolt on the rear upper face of the tcase, and see if the fluid is level with the hole. If not, add Dexron-Mercon II or III until it starts coming out the opening. Then, use a Mity-Vac to see if the diaphragm shift motor holds 18-19hg for about 15-20 seconds. If not, then the shift motor needs cleaning or replacing.

[J10rules]

I didnt even know that the 81 np219 had a vaccum.... Its all a manual shift. there is no vaccum. and the factory stamp says it takes 10w30 motor oil.

[J10rules]

I even just double checked. no vaccum

[Ryan]

sorry, I thought you said 229, which is what the above applies to.

On the 219, did you check the fluid level? And on the front, do you have automatic hubs?

[J10rules]

The fluid is fine, and no they are manual hubs. but its an awd system so the hubs dont do anything. Its always in awd

[Stuka]

DONT put motor oil in it! There was a recall several years later due to failed bearings. They switched it to ATF in 82 or 83, like every other NP t-case since then.

If you have manual hubs from the facotry, you have an NP208. The NP219 will destroy itself if you unlock the hubs and try driving. The NP208 is a part time t-case. It has 2wd, 4wd Hi, Neutral, and 4wd Lo.

The NP219 is mechanical shift as well. Its shift pattern is 4wd full time, 4wd lock, neutral, 4wd low.

What you need to do is look at the round tag on the back of the t-case. It will say either NP208J or NP219J. My guess is it will say NP208. Because if you have locking hubs that you have unlocked and driven, the ONLY way that t-case will move the vehicle is if its in 4wd Lock or 4wd Low. If its in full time, all power will go to the front and the VC will be destroyed in a matter of minutes.

Oh, and if you have a manual trans, they only had NP208's. I have seen a VERY few J10's with the NP219, but almost all of them had the 208.

[J10rules]

Its an np 219, when my dad bought the truck a long time ago they told him that he could buy a kit to make it part time. he bought the kit that they gave him, and no you cant make it part time, they were wrong. but he put in locking hubs anyway. they are just always locked. Yes its always in Awd because its a 219. Thats not my problem.

[J10rules]

and the transmission is automatic.

[J10rules]

I rebuilt my 219, and my truck is back in business, still the most badass awd system ever made, 219 all the way