Sorry, I meant NP129 "False Neutral" Issue

[eagle1phanatic]

Greetings Eagle Lovers. I've seen posts in this forum regarding the "false neutral" that can sometimes happen with the NP129 cases. I am familiar with that issue. But currently, I have a somewhat new problem. When I switch from 2WD to 4WD, the front drive does indeed engage, but the rear drive remains in the "neutral" position, permanently, while in 4WD. My car basically becomes a Front Wheel Drive Eagle. I've worked the shift mechanism manually to make sure it is moving the full stroke/distance needed to complete the shift into 4WD, but the rear drive remains neutral. Did something on the shift linkage inside the case slip?? Or something else preventing the rear drive from re-engaging when in 4WD?? If I need to drop this case and take it apart just because of a loose component on the shift linkage internally, that would be really frustrating. Any knowledgeable advice would be GREATLY APPRECIATED!!  Thanks.

[eagle1phanatic]

Has anyone ever taken an NP129 apart??  Has anyone ever seen the shift linkage inside??  I would like to know what it looks like, and what could possibly have slipped, or is otherwise malfunctioning.  Or maybe it isn't the shift linkage at all???  I've done a couple swaps, but never actually taken one apart.

[eagle1phanatic]

OOPS!!  SORRY!!  I meant NP129!!  DARN!!  SCHOZZBOTT!!

[eagle1phanatic]

 

[mo.eagles]

The EPedia has a parts exploded view of the trans cases . Are you sure your not in front wheel drive all the time even when it's in 2 wheel ?

[eagle1phanatic]

Thanks very much for the info mo.eagles.  Yes, I am absolutely certain that the front drive is engaging and disengaging as it should.  I've scrutinized this case in every way possible without doing any disassembly.  I've even tried getting the rear drive to engage while the car was moving, VERY SLOWLY, but moving.  No go.  My Eagle is currently either FRONT wheel drive, or, REAR wheel drive, but NEVER 4WD.  Daggon thing!!  By the way, forgot to mention, it's a 1983 SX/4 Sport, 5-speed, 258cid, Select Drive.

[eagle1phanatic]

So after finding a good quality diagram (exploded view), I have a clearer understanding of how the linkage works internally.  The internal fork is obviously in place, and moving correctly, otherwise it would not successfully engage the Front Drive components as it does.  Now I'm starting to think the case might be gunked up inside, from old dirty oil, preventing a component on the main Rear Drive shaft assembly to move fully into position.  I really can't think of what else it could possibly be.  So gonna try to "flush" the TC out one of these days, then refill it with a very good high-quality lubricant.  If that doesn't fix it, I'm guessing I'll need to drop it at some point, and get inside it.  Hope it doesn't come to that.

[DAVE]

refill with ATF, originally they suggested motor oil but a supplement came out changing that to ATF. could be its gunked up with motor oil

[eagle1phanatic]

Awesome!  Thanks DAVE!  My plan is to use Amsoil ATF.  Can't do much better (if any better) than that.