NP229 Linkage adjustment

[RAMBLINFSJ]

I doubt to many folks here have had to do this but I need to know how to properly adjust the linkages on a np229 t-case. I have a Haynes repair manual and I understand what its saying to do. The first thing it says to do is make sure the 2 links on the t-case are parallel to each other and that the rod for the vacuum shift motor is 5.9 inches in length. Well, the vacuum rod is at the correct length but the 2 links on the t-case are not parallel. With the vacuum switch in 2wd and the rod fully extended, that link on the t-case is all the way engaged toward the rear of the truck. When driving the Jeep, I am fully in 2wd. The link for the Hi/N/Low flag shifter in the floor is also fully engaged in Hi toward the rear of the truck but the two links are not parallel. I don't see how to make the two links parallel to each other without the flag shifter being shifted some where in between Hi gear and neutral. All that probably didn't make any sense but thats the best way I know to describe it. When I shift the dash switch to 4wd and shift into 4 low, the two links are parallel to each other. Any help would be appreciated! The problem I'm having is very little power to the wheels in 4 hi. 4 low works great and 2wd seems fine. This is the second t-case in this Jeep and both did the same thing in 4 hi. I'm working on this truck for a friend and he is counting on me to get all 3 gear settings right and working.

[Carnuck]

Is the adjuster tightened up? Sounds like front axle not engaging or mixed gear ratios.

[rockrollin]

What year? Does it have axle disconnect?

[RAMBLINFSJ]

It's an '82 and does have the disco-front axle but I've bypassed it. I've rerouted the vac hoses to the vacuum shift motor so it operates like a non-disconnect front axle Wagon. I don't have any problem with the vacuum shift motor operation.

[Carnuck]

It sounds like the front axle isn't engaged though. If you are fighting the viscous coupler trying to make it move with one end not engaged, that's exactly how it feels.

[rockrollin]

Have to agree, sounds like open ended front differential. I'm not picking up what your laying down as far as "bypassing" disconnect motor.

[Carnuck]

He hooked the hoses straight up. Unless the third port (closest to the linkage) is plugged though, applying vacuum to the middle port of the front axle shift won't engage 4x4.

[RAMBLINFSJ]

I have the vacuum hose to the front axle run to the vacuum canister for the cruise control since the cruise doesn't work anyway. Once the engine is fired up, the front axle is engaged. Since I've been adjusting linkages, I've had the front driveshaft removed so I can have some room to work. I wouldn't have thought the driveshaft needed to be hooked up for the t-case to work correctly?

[rockrollin]

The NP229 is a limited slip center differential, if the front os slipping much of the power will go to the front while in 4wd.