Hey guy's and gal's. i've got a 2000 s10 4wd , everything is working but my 4wd wont engage, my question is: how far does the vacuum canister pull the cable to engage 4wd in the axle? and how far should the fork in the rearend slide out to engage the gear's? thanks

 

The fork only moves maybe an inch, max. Maybe closer to 3/4". The coupler is only like 1-1.5" inches wide, so there's not much travel

 

Thank's Cleburne red , does this fork engage the 4wd in the rearend? And if it doesn't engage it, are the gear's bad? i had it off putting a new seal in and the fork and gear's looked good. i'm scratching my head on this one.

 

In the rear end? There is no engagement in the rear end. That's how the truck is driven in 2wd.

The front axle has a collar on the passenger axle shaft. In 2wd this coupling is open, and the front driveshaft is disengaged.

When you engage 4wd, the tcase shifts and the front driveshaft is now powered. At the same time, the coupling on the front passenger axle shaft is pulled by the vacuum actuator, connecting the two pieces, so that power can now be put to the front wheels.

There is nothing that happens in the rear

 

I too was a bit confused by "front rear-end" but then I figured it was like calling all facial tissues "Kleenex".

As for the lack of engagement, I've heard of people finding binding in the cable and engagement mechanism. But also, it is worth checking for leaks in the vacuum actuator and the system of hoses that supplies vacuum to the front axle actuator and the HVAC system. I have a link to the hoses I needed to replace my old ones in my signature below.

 

Ok, to clarify thing's , i'm calling it a front rear end because around here a axle is what goes into a rear end,lol Any how i was asking how far the fork is pulled out by the vacuum cable. I dont think it's pulling out far enough to engage the gear or "collar". When i have both front tire's off the ground the front driveshaft wont turn when it's in 4wd lo or high, this is correct, right? It will turn when not in 4wd. My vacuum actuator is working correctly and pulling the cable. When i got under the truck i unhooked the cable from the housing and pulled on the shaft that the cable pull's on, and it would'nt pull out but maybe 7/16 of a inch. i kept pulling in and out on it and little by little i got it coming out more and more till it's now coming out maybe 3/4 of an inch and returning back in. It's like it was corroded or something and i worked it loose. But i dont think it's coming out far enough to engage the axle. Is this making sense? That's why i was asking how far it's supposed to come out to engage the axle.

 

Start engine and put in 4WD Hi - make sure 4WD Hi indicator light is lit and not flashing. With engine still running, jack up JUST the passenger side front wheel (driver's front wheel still on ground). 1) Can you rotate the wheel by hand? If you can rotate the wheel without rotating the front driveshaft, then the front axle is not locked in. The lock-in is only for the passenger side front axle.

Probably something mechanical in your front axle. They are know to give some problems. See https://blazerforum.com/forum/tech-a...4hi-4lo-41226/ The distance spec you mention (1/2" to 3/4") is in the writeup. Maybe is OK now after you worked it loose??? Just check per above.

 

Thank' everybody, im gonna check it and see.

 

LOL i had a same mind blow as others reading "front rearend".
You have a feedback sensor that detects the engagement/disengagement of the diff.
Follow Les advice and check if they engage. If they do, then You may be having a problem with the feedback signal.
Just my $0.03

 

is this the sensor that plug's in right above the cable?