Alright ive been on here before asking around for things on my 4x4 system. Im pretty sure ive slimmed down my issues. Everything up to the front diff, the vacuums and all of that, work properly. My problem is after that. 4hi will not work, you can hear the transfercase however not the hubs. Now Christine suggested i jack my car up, put it in 4hi and try and spin front tires. If you spin the passenger tire, it wont do anything to the driver tire, and vice versa. So it seems as if my shaft is not engaging. Now ive looked at the cable that runs from my actuator to the diff. There is a little housing that the cable connects to the diff. If I were to remove that housing what is behind it? Could the cable perhaps be unhooked in there or could something behind it be froze up to not allow the driveshaft to work correctly? Any tips? (Also, just changed the 4wd indicator sensor, did nothing)

UPDATE……….
Today my father and I pulled off that housing. We pulled the plug that the wire goes into to see if we could manually engage the 4x4. It seems like gear #10 is just wore down which is causing the issue. Ill update next week to see if we have fixed it by changing that gear. family friend has a nice shop so we will take it there so we have room to take the shaft off to access those gears. Thanks for the help

 

There is a "fork" thing attached to the cable, when the cable moves so does the fork. The movement of the fork causes the hub ends to mesh, thus allowing the passenger front wheel to get power from the transfer case. It has been a number of years since I worked on this, so my memory isn't perfect, but basically this is what happens. Eventually, this will wear "mechanism will fail yet still show you are in 4hi or 4lo.

When this happened to me, I took the easy route and put a one piece axle from a Bravada in rather than fixing the two piece that was stock. I figured out mine was bad when I really need my 4wd to work. At least with the Bravada axle in there, I know that if I lose 4wd in the future, I have one less possible cause to look at.

My son's Blazer had this problem a couple of years ago. He ended up finding a place on line that manufactured the axle, as finding a Bravada in the parts yard is damn near impossible today. I don't recall how much he paid but I think it was around $400-500 and paid to have it installed. It's a pretty easy swap, though. I don't recall the name of the place, or the web site, but he did have to wait about six months to get it, as the folks that make them wait until they have enough orders to make a run of them.

As the years pass, less and less folks will do this mod. In my mind, this is one of the best mods I have done on my Blazer. I can shift my transfer case manually if everything else on the 4wd system fails fairly easy on the transfer case itself. That gives me peace of mind should I lose 4wd again when I am nowhere near civilization. Simple tools, easy fix, providing I can get under the Blazer.

 

thanks Aj, I will pop that open and see if that fork is worn out. I have a few big junk yards around my area so if I need to fix that ill look for possible a bravada axle or just bite the bullet and deal with replacing the fork

 

Here's a link to a great website that has exploded diagrams for Blazers (along with other cars).
https://nemigaparts.com/cat_spares/epc/chevrolet/54s-t/

This is the diagram for a non-Bravada front differential that has the drive axles that get pushed into the case rather than bolted on.

If I remember correctly, do not start taking off parts for the front differential. There may be issues with shimming parts of it that you don't want to mess up. (see attached file)

 

Thanks Christine!

 

Alright so im about 90% sure that gear #10 on this image is my issue. The other thing cannot slide over it to engage 4x4. So we will have to take the passenger shaft off to access this gear to change this. Is there anything else that I will access from the passenger side that I should change along with this gear?

 

I'll reference the exploded view Christine posted and say that you want to inspect #9, #12, & #23. #9 is the passenger side connector gear, #12 is the front axle engagement clutch sleeve, and #23 is the passenger side differential output shaft. Since the clutch sleeve is always engaged on the output shaft and engagement happens when the sleeve is pulled over the connector gear, wear/damage occurs between the connector gear & the clutch sleeve. So you'll possibly be replacing #9 & #12 depending on the extent of damage that has occurred.

I have combined your two threads as it is best to keep your questions on a given topic in one thread so everyone can read what others have already provided for advice and supplement as they can without jumping across different threads.

 

Alright I’ll check those parts out aswell and see what they cost. Thankyou

 

Here is what you may find on the connector gear:

 

Could the shift fork possibly be gunked up and stuck, or possible rusted out. We tried to move it and we could only move it 1/8 inch, by the time we were done messing it moved about a half inch. Could we need to lube it up with wd40 and pull it more? When my car was off and i spun the passenger wheel and my father pulled the fork you could hear it trying to catch on to the gear. We turned it on and put it in 4hi but it wasnt catching on the gear anymore. Anything this could mean?