4 wheel drive does not work
Asked by Robert_Holland_073 Dec 17, 2009 at 04:06 AM about the 1994 Chevrolet Suburban K1500 4WD
Question type: Maintenance & Repair
When I put the Sub in 4 wheel drive, low of high, only 2 wheels do the driving. I hear no strange sounds, it just runs like I put it in 2 wheel drive. I live in Holland europe, not many can help me out I am afraid.
I red the forum, and putting it in "on the Fly"( at low speed) or in N or P, backing up, nothing changes it. Thanks for any comments.
Robetr
7 Answers
its all in the axles. if you have standard axles you are only going to have two wheels driving the truck. the opposite wheels. like the driver's front and passengers rear. if you have limited slip axles or possi-trac then all should spin.
migration_jml12345 answered 14 years ago
you do have a point there, but what if his chevy was equipped with a vacuum pod on the t-case? if that fails or if the hose comes off it can do the samething.
it also can be the actuator that locks in the frount hubs. if you don't engage your 4wd atleast once a month it can seize up and then the trans case may ingage but the hubs won't be locked in so it could be a problem in the hubs. i have also heard of the circuit board once it gets wet the 4wd will not disengage so it would work in the other way where it would not engage. and that is like a $500 (US dollars) fix
migration_jml12345 answered 14 years ago
thats true if its a part time axle, but we dont know forsure.
If it's a 94, then it's got a manual t-case, so that shouldn't fail, but there is a sensor that detects when you put it in 4x4 that sends a signal to an actuator up front to lock in the CV axles because it's got independent suspension. you should have a friend put it in 4x4 after you unplug the harness on the actuator to see if it's getting an electric signal with a tester, if it is then it is the actuator up front, if it's not getting a singnal then it could be the sensor on the shifter or a fuse. hope this helps.
Have some one watch ur main drive line with the sub. in 4wd. Just put it in drive and let it roll at idle speed.you should be able to see the main drive line going to the transfer case turning. From there u should see a drive shaft going to the front, if that's not spinning then ur transfer case isn't working for some reason. If it is spinning, then ur hubs aren't locking in. From there it all depends on if u got vacuum seals or turn out hubs. U could have dirt or somthing stuck in the hubs, a hose blown off ur t case or even as simple as a fuse I'd they auto lock. Odds r you t case or hubs went tho. If u replace hubs get turn outs. Not as convenient but better connection and less chance to fail
On my 2000 Blazer, it was a vacuum leak. look for a vacuum line not plugged into anything. Plug it up and see if that helps. You may find that something else doesn't work either. (like your heater?)
