Covered in many other threads. How far is the cable being pulled? It needs to move around a 1/2" to engage the front axle. If that still doesn't do it, then you likely have an issue where the cable connects to the shift fork in the front axle.

 

the cable is definitely being pulled far enough i checked by starting the truck removing the battery and tray then having my cousin engage the 4wd and it's pulling it far enough. I am going to my dad's house later i will check where the wire goes into the fork. i will tell what i find.

 

i just have a question. I have not been able to pull apart my differential and look at the shift fork yet but if it is stripped or worn could i possibly weld the 2 shafts together or would that cause a major problem.

 

I doubt you would get it to hold.

 

Can you please elaborate on this Kyle. I had the same issue with my '02. My 4wd engages but my HVAC system appears stuck on vent. I did find ATF contamination in my vacuum lines under the dash and in the engine bay. I systematically disconnected all the lines and blew them out as best as I could. At the same time I changed the transfer case vacuum switch which did show signs of contamination. Is this a factor of a faulty seal in the transfer case, a bad vacuum switch or a combination of the two? Does the switch fail because the seal in the t-case has failed? If the route of all these issues is the seal, how difficult is this to fix? I'm gathering this is a common problem. My mother has an '00 Bravada with Smarttrack 4wd. When she makes a tight turn the car starts "bucking" like a bull. Our mechanic told us that the fluid (I'm not sure what it is but I know its blue) becomes contaminated and needs to be replaced. This contaminated fluid causes erratic 4wd engagement and disengagement. We have done this approx. 6 times with her car. We see immediate results after replacing the fluid but the issue eventually comes back. If you could provide some insight on both of these issues it would be greatly appreciated. Thanks in advance.

 

Remove the fill plug on the back of your transfer case. If fluid pours out, the input seal is bad.

On the NV136 transfer case in the Bravada, sounds like the clutch is bad. I would be looking for a replacement NV136 for it.

 

Are the NV136 transfer cases used both on the Blazers and Oldsmobiles? I believe I found the seal you are referring to:

http://www.rockauto.com/catalog/moreinfo.php?pk=1118669

I see no reference to the NV136 but Rockauto lists this for '02 Blazers. Do you think the faulty seal caused the vacuum switch to fail or the failed switch caused negative pressure in the t-case causing it to suck in fluid? Do you have any reference drawings on the transmission / transfer case that might show this in detail?

 

The NV136 is in the Bravada.

Your truck could either have the NV233 (3-button) or NV236 (4-button) transfer case.

This is why it is bad to bring up two unrelated things in one thread...

 

By taking off the shift mechanism-cover on the right side of the differential (3 bolts), you can test if the cable is still on the shift fork by pulling on the housing. If the housing comes apart completely(so no attachment no more),then probabely the cable -clip on the shifter loosened.It is held with a sort of clip-spring. Try to push the cable back in by holding it through the hole of the switch on the housing ( which You can take off easely)with a nose plyer, if the cable pops back in and stays in by pulling (and someone trying the hubs)o.k. If still no engagement, You probably have to change the CARRIER conector (oem # 26047584). This is a mayor job but "do-able"

 

ok i have been trying for a while to get on here but i tore my differential apart thinking maybe there was some broken thrust washers inside. took it apart, nothing. put it back together checked everything again and still no 4 wheel drive. i looked at all the parts inside and everything seemed fine. this thing is just starting to be a hassle.