96 GMC Jimmy 4WD--non motorcycle

[frankd]

My nephew just called me up, and he's got a problem with his 96 Jimmy that he's having problems fixing. He has replaced the vacuum actuator in the transfer case and he still doesn't have 4WD. He's not 100% certain that he has the vacuum hoses in the correct locations. He has it on 4 jack stands, and when he is in 2WD, the front hubs ARE engaged, but as expected the transfer case is not connected to the front drive shaft. When he engages 4WD, both the front and the rear drive shafts turn, but the front wheels do not.

 

Then he went on to tell me of a couple other things.....He says from the front of the truck, he can hear what sounds like gears grinding a bit when he engages 4WD. Also, he says that the truck isn't going into 4th gear at highway speed and it's very sluggish taking off. It sounds to me like he has a transmission problem in addition to the 4WD problems.

 

Does anybody have any ideas what he's got wrong or maybe a 4WD forum that'd help him out?

 

Frank D.

[Wrench]

I had a '96 Blazer, which is the same setup. The transfer case on those has an internal chain, similar to a timing chain, that drives the front shaft. The selector switch on the dash could be bad, but I'd start with the servo motor on the side of the transfer case and make sure it's working. It's pretty easy to get to once you get the skid plate off. The servo motor just bolts to the side of the case, so you can drop it off and check to be sure it's working, but everything under there is a tight fit. While you've got it off you can use a wrench on the shaft of the transfer case to manually shift it to make sure everything is good in the case. Mine went out during a big snow in '05, so I just left it in 4-hi til I got the part. Hope this helps.

[stroker ace]

More than likely it's the front differential actuator, especially if the drive shaft is spinning. The axle is not check the vacuum to this or replace.

 

 

 

http://www.1aauto.com/1A/4WDrive/Chevy/S10-Blazer/1AFWA00002/152059/1996?utm_campaign=gb_api_br&year=1996&utm_medium=comparisonshopping&utm_source=google_base&utm_content=FWA&gclid=CI6Rka3OhrUCFQq0nQodNWcAYw

 

http://static.1aautoimages.com/partphoto/FWA/1AFWA00002/middle_2.JPG