The shift fork should move the same distance that the actuator moves the cable. the fork sets the limits. One thing to consider is that the splines inside the passenger side extension tube may not be lined up as the truck is sitting there. You may have to jack up the passenger side tire and turn it slightly to allow the shift collar to engage onto the passenger side axle shaft.

 

I did actually jack up the passenger side, after a few minutes, while I pulled on the end of the fork. While rotating the tire I still could not get it to move more than about 3/8 inch. I clamped vice grips on it, pryed it out as far as I could, and did get the front drive shaft to move. But, it was obvious to me that something is not right in there. I could only get the front driveshaft to move when it was 'out' as far as I could get it to go. This is why my actuator was not moving as far as it should.

Any ideas? It looks like I,m going to have to tear into the front axle, doesn't it????

Thanks again for your time.

 

similar problem - no front axle engagement - actuator test ok with cable disconnected - can only move collar shaft 1/8 inch by hand at the diff - already replaced failed vacuum switch at transfer case - 4wd(3 way) switch lights do flash & lock (sometimes) as selected but no action at the axle - no lights at all in testing 4wd switch through grounding pin 13 at aldl - is there anything short of removing/replacing front axle ?

 

Sounds like you need to pull the passenger side extension housing and take a look at the splines on the stub shaft and passenger side extension axle.

 

I have problems similar to what has happened here. I have a 98 jimmy. I do not have auto 4wd. Just 2wd, 4hi and 4lo. I can push the buttons to go into 4 hi and 4 lo and they'll stay lit and I can hear the click, however it will not engage. I took the battery tray and battery out and the actuator is fine, although when i took it all apart and squeezed it oil sprayed out. Is the switch on the transfer case bad? Would I have to replace all 3 parts(actuator, switch, and vacuum hose)? The actuator still holds vacuum when everything is connected. This all happened after I had my transmission replaced. I've done extensive amounts of research and haven't read anything about oil being in the actuator, but if there is I apologize.

 

Fixed - removed axle extension to find broken thrust washer and badly worn gear - Thanks for the education.

Re oil in vacuum actuator - read it in here somewhere - should be broken switch in tc - should be able to clean the lines but don't know how you would clean actuator.

https://blazerforum.com/forum/tech-articles-diy-29/4x4-no-worky-maybe-will-help-7180/

This link should tell you most everything you need to know.

 

In my "TEST" NV233 which works perfectly, I set it up on the bench, disassembled an encoder switch and a motor assy. Laid the switch on my flat bed scanner and inputted it into a CAD system, then worked for hours moving the shifter sector gear carefully, counting teeth as each "engagement" in the TC occurred and developed this picture.

I think this describes everything that goes on, at least on my test bench NV233 as the shift motor moves the sector from end to end.

The position of the sector gear is indicated in my drawing by DEGREES on the gear. Reference is "4HI-Detente" as "0" and extending to 4LO at 330. I've extended this scale in each direction for obvious reasons; The assembly and switch is designed to operate beyond the ranges required somewhat.

There are two large wires, Red and Black. These run the motor which has substantial planetary reduction and produces ample torque to move the selector from end to end in about one second.

There are 5 smaller wires known as Common (ground) A B C P. I have indicated on this drawing which positions each of these four lines is "grounded" thru-out the range.

Note that A B and C are over-lapping channels which give the computer a good idea of about where the selector is. the "P" channel has six short positions where it grounds. Three of those are "illegal" on the NV233, one out of range CW, one out of range CCW and one near the position where the HI-N-LO selector might have been in N, but not quite lined up with this N. My guess is the manufacture considered a "N" position and had it included on the Encoder Switch, but on my model, the computer simply ignores this.

The other three "P" positions seem to be the "correct" or "detente" positions for 2HI 4HI and 4LO.

I built a test harness with a connector I cut out at Pull-A-Part and wired up 4 LED's Purple, Red, Green, Blue for this testing.

Anyone who removes the Encoder assembly from a NV233, should note that there are two mating surfaces when they go back together. The Outside of the Shifting shaft on the TC mates to the inside of the sector gear in the Encoder. The inside of the Shifting Shaft mates to the Encoder Switch shaft. Look into the encoder assy once you remove it from the TC and you can see both the Sector Gear and the smaller switch. This switch can be turned carefully and easily with some needle nose pliers if it is needed to align.

Hope this info is helpful.

 

Here's a few pictures from the NV233 encoder motor I removed from my uncle's '99 Sonoma and dissected:

And a schematic overview:

 

This drawing is accurate for 4lo 4hi and 2hi but does not accurately indicate the "P" possitions for N or CCW overrun. 18 rather than 20 for the P pulse for "N" which does not coincide with the actually "N" of the NV233 which occurs about 13deg instead. While the over-run P pulse is not important, the "N" pulse could be if someone was actually trying to force their TC into "N". Also, they would need to know that while the Tranny is disconnected from the axles in this position, the two axles are still connected together. Might still be ok for towing w/ a tow bar, but probably on a dolly!

 

I just pulled that out of an article on RS Gear. It's close enough if someone were to be trying to find that location. They wouldn't have the benefit of the encoder motor to tell them where they were if they were manually actuating the transfer case, but technically, they could hotwire the encoder motor to force it to that location if they were monitoring the 'P' channel continuity to the common (providing that the gears in the motor were working properly).