np 229 tcase shifting info

[clavin001]

I have a 84 full size with v-8 auto and an np 229 t-case and was wondering how the factory recommends shifting from 2hi to 4hi. Also, can I shift into 4hi on the fly? The only way I can get the tcase into 4hi is to slide the selector to 4hi and put it in reverse for around 10ft which doesn't make much sense. I don't believe there are any vacuum leaks, but I haven't checked.

[joe]

On 83-84's w/229 you have to be stopped to shift between 2WD/4WD...no shift on the fly. Pull the release pin and then shift the switch. You very well may have to roll a bit afterwards for everything to get lined up/engaged. On later Wags w/229(85+) you can shift on the fly but yours also has a vacuum actuated front axle the later ones don't have. The x-case will shift on the fly but your front axle won't and it gets vac first when you move the switch. That's why AMC made it a two hand operation to throw the switch.

[FrankenJeep]

The factory also recommends running 100 miles or so every month in 4HI for T-case lubrication purposes. I don't know if thats a good rule of thumb tho ... the PO burned up the NP229 before I bought FrankenJeep.

[Joe H.]

I never heard 100 miles.....5 minutes or so is what I was told. Is that enough?

[clavin001]

As far as "very well may have to roll a bit afterwards" If the t-case is switched from 2hi to 4hi and driven forward, the truck will not be in 4wheel drive (rear wheels spin only). But if shifted to reversed and reversed for approx ten feet, then placed in drive the; truck will be in 4wheel drive(front and rear wheels spin).

[tuckers89GW]

You should here 2 seperate short hisses when it shifts into or out of 4wd. kinda like shhup-shhh. I'm not sure why you would have to back up.
Start by inspecting all your vacumn connections then lub the heck out of the shift linkage attached to the vac motor at the transfer case. make sure that all works like it should. I wonder if you are short on vaumn.

OH, check your t/c fluid if you haven't yet. or better yet change it. its just transmission fluid in a np229.

[Ernzo]

when going into 4H on a 229, the way it works is the vacuum triggers the front axle first, then routes the vacuum to the t-case. The t-case cannot shift into 4 unless the front vacuum motor has been fully actuated. however, the front axle shift collar that locks the axle may not be perfectly set. one test is to jack up one front tire off the ground. shift from 2 to 4. try to spin the tire. if it is shifted, it will not turn. the jeep book indicates that a little back and forth may be in order to effect a shift into 4 from 2. be REAL careful that when going from 4 back to 2, the t-case is FULLY shifting, that is returning the shift lever to the 2 wheel drive position. while going into 4, the axle shifts first, the reverse is not true. mine fried as the front axle was not engaged, but the t-case had not fully switched back, unbeknownst to me....