Front output housing installation troubles

[masonater]

Ive been trying to sort out why my 109 has not be able to shift into 2wd since the rebuild. Checked and rechecked all the obvious stuff. Im sure its something i did wrong while attaching it last winter. I think the problem is with the red lever action. I cannot get it to disengage 4 when i pull it all the way back. The yellow knob pops back up like it always has but its still in 4 hi. Ive been staring at the picture diagrams in the green bible trying to visualize how it all works in there. I suspect that one of the pins that hook in that pivot point was not in properly. (im making up terms for the parts) Im having a heck of a time trying to get the housing back on now after seeing how it needs to go together. I cannot get the shaft that the 4wd pin goes into to come out the front of the housing. Im fighting the springs trying to slide it back onto the studs and once i let go, the housing moves (springs) forward again. Is this because 4wd is still engaged?
I would think it would go on much easier that it is. I probably didn't make much sense to most people including myself. If anyone has an idea of what im up against im open to any ideas. I spent all day in and around the truck today and no luck...

thanks, mason

[SafeAirOne]

Presuming that you didn't disassemble the pivot mechanism up front, the only way I can see that the yellow knob can pop up and still be in 4 wheel high is if the selector fork is behind the 4WD dog instead of in the groove. That or the spring on the front of the 4WD selector fork is weak/missing or the spring on the rear of the 4WD selector fork is somehow too strong or, more likely, is not seated properly.

PS: Good pics of the front housing innards can be found here. The simplicity of this shift mechanism is pure art.


Here's a Sketchup drawing I did to illustrate what I'm talking about:

[masonater]

Bingo!
I did not disassemble the pivot mechanism so i was hoping it was something simple. Thats exactly what i discovered during round 2 after i ate and sat on it for a while. I noticed the fork was behind the 4wd dog when i separated the housing. I wasn't sure if it fell out of place when i moved everything or if that was my problem. Those are some serious computer graphic skills SafeAirOne. Nicely done and i have an much better idea now.
I'm still having trouble sliding the housing back on once i have the fork where it needs to be. I cannot get the lower of the 3 shafts (one that pin goes into) to line up and go through the front of the housing. That and there seems to be a lot of spring tension fighting me.
Looking at SafeAirOnes graphic, is that what the system looks like in 2wd? My pivot point with the pins is currently in the opposite orientation (the other way it goes). Can i still assemble it in this way?
Thanks for the help! I have yet to drive her properly in 4 years, some heavy duty excitement is building as im nearing the bottom of my check list.

[SafeAirOne]

Looking at SafeAirOnes graphic, is that what the system looks like in 2wd? My pivot point with the pins is currently in the opposite orientation (the other way it goes).

Yes...Except for the fork out of the groove, that's the orientation for the rods and pivot in 2WD. If your pivot is the other way, then it is probably in 4 low gear.

[masonater]

Thanks for all the info. I managed to get it all back together with the help of another member of this board. Put the levers back on and i have 2wd again! It was defiantly the fork being on the back side of the dog that caused my problem. very happy until.... i managed to snap off a stud on my T-case bottom cover, that i should have not touched in the first place.

[SafeAirOne]

BTW, Here are drawings of all 3 modes looking up from below:



2WD: 4WD selector shaft held to rear, pushing 4WD dog off front drive gear. Yellow knob pin engaged in center selector shaft (pivot). High/Low selector shaft all the way forward.





4WD HIGH: Yellow knob pin disengaged from center selector shaft (pivot). Spring pressure pushes the center selector shaft forward, with the pivot arm rotating under the stationary high/low (red knob) shaft. The 4WD shaft is pushed forward by the pivot mechanism, causing the 4WD dog to engage the gear on the front output shaft, coupling them togeher:





4WD LOW: High/low selector (red knob) shaft moved all the way aft, engaging low gear (not shown). Pivot mechanism pivots under the stationary 4WD selector shaft, bringing the center shaft (pivot mechanism) back until the yellow knob pin drops into its hole in the center shaft, locking the pivot mechanism in place.





Then back up to the first drawing...Pushing the high/low selector shaft (red knob) forward causes the pivot mechanism to pivot over the center shaft (now locked in postition by the yellow knob pin), pulling high/low gear (not shown) back into high gear and pushing the 4WD selector shaft backward, disengaging the 4WD dog from the front output shaft.

A truly beautiful system that's elegant in its simplicity!

[masonater]

SafeAirOne, great pictures. Did you do that your self? They were very, very helpful.

[SafeAirOne]

Glad they were helpful.

Yes. Did it myself. Pretty easy once you're familiar with Google Sketchup, the free CAD software.

I figured out how to animate it last night. The video of the mechanism as you cycle the yellow knob, then the red knob can be seen here.

[bmohan55]

Great easy to understand information here! I hope I never need to refer to it though but just incase I'm bookmarking it!