My sons 2000 Blazer, 4wd took a dump,,,, will not move. Drive shaft spins,, but a nasty clunking in rear differential. so broken axle [s] or gears are tore up,, will know Monday when we pull pumpkin cover.

So,, in the meantime,, when he hit the 4wd rocker switch,,, Blazer still did not move,, front shaft spins,, but vehicle did not move,, he said he used the 4wd a lil' while back, and sure thought it worked,,,, if you have a failed rear differential,,, should the Blazer at least move move in front drive only,, or,,,,,,,does the front need to feel the rear doing something,, before it joins in ?

 

it should move, front not engaging, maybe vac. actuator under battery

 

ok, then with no rear drive train , the front drive should pull the vehicle,,,,, ?

I just rebuilt the front end a year ago,,,, that engaging gear in the differential was worn off, plus changed the vacuum controller on transfer case and replaced a vacuum line,,, just did not think that would fail again this soon,,, with just periodic 4wd [ VERY slight use ] use.

 

when you engage the front dif, does the front driveshaft turn freely/? it shouldnt.

 

well,, when it was along the road, he put trans in drive,,, 4H, both driveshafts would spin,,,, I just thought there was something that would not allow the Blazer to move, without rear power, since the vehicle was not designed to be front drive only, I thought [was hoping ] that without rear drive,,,,, the front would NOT act as a stand alone drive source,,,and not move,,,, like a broken axle on an open rear end,,rwd,, or something similar,,,

 

What new guy is asking is if you put the truck in 4wd and try to spin the front driveshaft by hand does it move? If it does, it shouldn't and there is something wrong with the front diff

 

yes I get that,,,, but if front drive shaft spins,,,, when in 4wd,, and in Drive, motor running,,, and blazer does not move,,, isn't that the same test ???

the front drive is really part 2,,,, our first assignment is to get the rear differential to make the blazer go,,,,, all this depends on part costs,,,,may fix it or throw it away,,,,,,,

As far as the front drive ,, what you guys are saying is, that no matter if you remove the rear drive shaft,,,,, or have a broken rear end ,,if you put transfer case in 4wd, then trans. in drive you should be able to drive the vehicle around the yard ?

 

Yes. If 4wd is working then you should be able to pull the vehicle with only the front wheels.

 

thanks for the info,,,,,,,, did not really want to hear that about the: front only should work,,,,,,,,,,,,ugh,,,,,, but then again,, that is part 2,,,,,, will see what part 1 entails,,,,, thanks guys,,,, this is not a daily driver but a bomb around vehicle for occasional snow days,, and pulling his boat in the summer,,, not sure it merits a lot of $$$ for repairs,,, thanks again guys,,,,,,,,,

 

2000 Blazer LS 4wd 4.3L:

We took the differential cover of the rear end,, spider gears are bad, so when replacing the spider set, there are several options,,,,according to the tag in glove box, it has a 3.42 ratio [GU6]


Will the Vin # ,,,or a number in the glove box tag, tell me which one of these gear kits is the correct one to order ?

in other words, is there a chart that defines the RPO codes,,,, and would they tell number of axle splines, 8 or 7.5 in rear end,,,, I was hoping to order parts before tear down.

Example: http://www.autopartswarehouse.com/se...0&addfitment=1