Hi guys, I recently started hearing a whine/grind from my front end of my blazer, at first it was on and off, but now it is permanent. Its a grind like a wheel bearing but it isnt as far as i can tell, I crawled underneath and on the right passenger side where the front axle couples into the cv joint it appears that there is a seal worn out which was leaking gear oil.. I opened the fill plug on the front differential and stuck my finger inside, there was not much oil inside it so i filled it with gear oil reccomended by the manual and took it for a spin. I still have the grind... This grind is not present in reverse(At 30mph) it goes away immediatly when putting into 4x4. 4x4 is still fully functional and working.. and grind is now present at all times in forward when in 2 hi. Is there a bearing where this seal is? which may have worn out or did i screw up the front differential?

 

Yes there is a bearing behind that seal. There are a number of other bearings in the front axle including the typical differential carrier and pinion bearings, along with inner and outer bearings for the intermediate axle shaft on the passenger side. I would rule out the wheel bearings before i considered any internal failure, however if it was significantly low on fluid you very well could be right.

here is a breakdown of whats inside... hope that helps.

 

okay and by ruling out the wheel bearings i would simply shake the wheel left to right correct? i just found it odd that it didnt grind when going in reverse and that it immediatly stopped when going into 4x4. We shall see i guess.

 

Sounds like THIS maybe?

 

Bingo! I didnt feel like taking the battery out of the car etc, to figure out if it was a vacuum issue so i went closer on the back firewall and unplugged the vacuum tee that is feeding throught the truck.

The clicking/grinding stopped. I plugged the tee back in, went to the top of the transfer case and got as far as unplugging the vacuum lines on top of the switch that is probably bad. I am wondering the best way to get this mechanical switch off the top of the transfer case. I got a 7/8 socket on it, and i cant get the wractchet on it. let me know what i can do!


thanks for the help so far

 

I found that putting the ratchet on with the handle pointing towards the rear of the truck using a flexible head ratchet works pretty well.

 

okay, i have replaced the transfer case switch, and all went well, but i dont have 4x4 from what i can tell. I can do tight turns etc, without the front end jumping around. i tried it in a bit of snow and it slipped around as if it were in 2 wheel drive. the 4 hi and low lights both work fine, the transfer case drive shaft locks up, how do i tell if the vacuum actuator is shot?

 

okay ,I took the battery box out and got to the actuator. It is not torn, the cable pulls freely and retracts. I hooked the battery up, and started the truck and left it running as i took the battery out and had someone put it from 2hi to 4hi and the actuator moved very little.

I pulled the actuator in, clamped it as best as i could, initially the truck was in 4x4 front differential locked up because i turned and it started to hobble around, then a louder clunk sounded and it wasnt in 4x4 any more(the clamp was still on) i think i have a vacuum issue

anyone know my next step, i dont know where this black ball vacuum hose thing is that people are talking about

but i am making progress, as the grind has not re-appeared.

okay, not to keep updating myself, but to keep everyone else informed:

I put the old(apparent broken one) back in, after rechecking that i had no torn hoses and my vacuum adapter was tight on the switch and with the old one back in the 4x4 works flawlessly

i now know that the switch i bought today has got to be defective.

the grind is still gone, but that doesnt mean it wont come back. when it does, ill just unplug the vacuum tubing again and see what happens.


im stumped, but im certain that the old switch, which i just put in is definatly defective(the ball/ spring at the bottom is stuck in the depressed mode as if i was to press it against a table it would recess. its stuck recessed.