Front diff. wont lock into 4x4. Transfer case is working. Vacume Dia. under battery tray is working. Could the shifting fork in the diff be broke
The cable from the differential to the accumulator should move somewhat freely. If it does not, then the cable
may be froze up. You can lubricate it with some penetrating oil and
work it to free it back up. You may have to remove it to free it up
properly.You may find the cable shield towards the bottom end is broke off and the cable may completely be froze up, it's common on the Blazers. You can try pulling on the rod that the cable clips into in the front
diff to disengage the front axle. If you cannot get it to engage
that way, then you will likely have to pull off the passenger side
extension housing to access the engagement collar and fork. If you cannot get it to engage by pulling on the fork in the axle, then you will likely have to disassemble it.
You will likely have to file down the leading edge of the gears. They
should be beveled on the sides of the spline to aid in engagement.
Hopefully yours is not chipped like the one in the front of my old S10.
Mine chipped the splines on the axle and split the collar from being partially engaged under power
The right axle and has splines at the end of it. The Output Shaft slides into the carrier and has large teeth on the other end. The collar it has large teeth inside it that mate with the Output Shaft with the Fork.
The collar rests on the axle, the fork wraps around the collar.
Then you push the 4x4 button or shift your transfer case into 4x4 it
starts spinning the front drive shaft, which spins the carrier and the
short shaft. Now your in 4x4, BUT the front axle needs to lock
the right axle with the carrier. A switch on the
transfer case routes engine vacuum to a diaphragm under the battery
tray, that diaphragm pulls a cable which pulls the collar and forces it over the short shaft. Now your front diff is
locked. When you take it out of 4x4 the vacuum switch closes and a
spring pushes the fork and collar off the shaft unlocking the front diff.
The problem with mine I think is that the large teeth on the Output Shaft and the inside of the collar
are worn at the tips, not allowing them to join together, and the more
I drove it around with it clicking, thinking it would lock eventually
it just wore the tip of the teeth more.
If that is the problem, You should not have to mess with the differential case. You should be
able to get the passenger axle extension tube off, but it may require
popping a ball joint, then disconnecting the CV shaft from the axle
extension tube, which would allow you to then pull the extension tube.
Good luck and hope it's just the shift cable retaining clip in the housing that broke.
Dec 30, 2009 |
1997 Chevrolet Blazer