96 Chevy Tahoe 4hi not engaging

[xlrdxrevengex]

Alright so i have read over a lot of threads about this issue and rather then hijacking someones thread I will create my own. My issue is that i can change from 2hi to 4lo using the way describe in the owners man. but what I can not do is go from 2hi to 4hi.

I have done some of the tests I have seen on here about checking the fuse, listening for a click and clunk etc.

When the key is in just the run position you can here the I am guessing the actuator making some noise under the truck as well as a click in the cab. Now with the engine running you can here the clunk of 4lo engaging and working along with the light going solid but I get no new feedback for 4hi what so ever.

Before i go by some parts I am just curious on what you guys/gals think. Below is a look of the parts I was told to try from two different part dealers and am a bit confused as one looks like nothing i have but comes up under the truck on part finders.

Orileys Auto: Transfer Case Switch
http://www.oreillyauto.com/site/c/d...=Search_06603_5003183_3803&pt=06603&ppt=C0316

Autozone: Transfer Case Actuator
http://www.autozone.com/autozone/pa...o34b?itemIdentifier=594772_498678_22440_23551

So my main question to you folks is which part would be the one I would want or what else could the problem be. I see a complete different part one being an actuator and one being a switch.

Below are a couple images of what i see.

 

[SunlitComet]

if the actuator and feed back switch work in 4 hi then they will work in 4lo. the part that can effect whether it works would be the tcase shifter, the tcase power switch above it which applies power to the front actuator, or the shift cam inside which pushes on the power switch. I would make sure again that in 4hi everything is fine. If so you can try the transfer case switch but I think you have the wrong one listed. I believe the '96 had the three pin switch. One of those pins was used to signal pcm that power was applied to front actuator. That would be cheapest before suspecting a shift motor or internal problem. You can run an amp meter in line with the front circuit to see what the power dose when you switch into various modes.

 

[xlrdxrevengex]

if the actuator and feed back switch work in 4 hi then they will work in 4lo. the part that can effect whether it works would be the tcase shifter, the tcase power switch above it which applies power to the front actuator, or the shift cam inside which pushes on the power switch. I would make sure again that in 4hi everything is fine. If so you can try the transfer case switch but I think you have the wrong one listed. I believe the '96 had the three pin switch. One of those pins was used to signal pcm that power was applied to front actuator. That would be cheapest before suspecting a shift motor or internal problem. You can run an amp meter in line with the front circuit to see what the power dose when you switch into various modes.

Ok so bit of more info as i forgot to include this. 4 hi will not engage at all no matter what. Also it just stays blinking and never goes back to the previously engaged one. Even if i turn the truck off and back on 10 minutes later still in a blinking state.

As far as the 3 pin thing goes I only saw two wires coming from the OEM part. Now i have seen some diagrams that show a little sensor deal or something along those lines right above the actuator i believe.

Now maybe im looking in the wrong spot under my rig but i should be looking up by the front axel right?

Is there any diagrams that can go along with where i should be looking for these parts?

 

[SunlitComet]

the one on the front axle is a feedback switch that tell the TCCM that the front actuator has engaged and locked the right wheel with the left wheel (which is always in direct connection with the carrier. in 2wd the right is disconnected from the carrier so when the tcase is not putting out front rotation the wheels are in effect independent of each other. the left wheel just spins the spider gears in the carrier all day long when in 2wd while the whole carrier stays stationary.) The front actuator and its feedback switch each have to wires I was referring to the tcase transfer switch on the tcase above the shift motor(again on the tcase).

Included elow are the diagrams. To be simple, with the key on and the front axle actuator(#19) remove but wired up put the tcase in 4hi. listen for the shift and see if the front axle actuator extends. if not probe it wires according to the diagram to see if it has power. if so replace the actuator. if not test that connector that go to the transfer case selection switch on the tcase(#72) to see if power flows thru it when 4wd is set. if no power on the light blue but the brown wire does then the switch may be faulty or the sector cam(#68) inside the tcase that actuates it or the shift motor(#83) is not completing its part.

http://www.sunlitcomet.com/pdf/auto...oe-NV243-Transfer-Case-Electrical-Diagram.pdf

http://genmotorinfo.com/FullImage.a...VENTURE+GEAR+243C)+-+K1,2+&pid=990414TX04-002

http://genmotorinfo.com/FullImage.a...+AXLE+(L31/5.7R)+-+K1(06)+&pid=060205TX06-057

---------- Post added at 11:12 PM ---------- Previous post was at 11:10 PM ----------

also the switch on the tcase may end up being two pin version after all I think it was the diesels which had three according to the diagram. just pull the old one to verify if needed.