4wd?

94sierra16 · January 31, 2014

Ive got a 94 gmc sierra and the 4wd isnt working. I checked the fuse and its not blew what else can i check?

kstruckcountry · January 31, 2014

Is it saying it is engaged?

94sierra16 · January 31, 2014

Where would it say its engaged at?

aapluna · January 31, 2014

what style hubs is on it? are the manual,air,automatic?

aapluna · January 31, 2014

easy way to diagnose it is to engage 4wd and have someone look and see if drive shaft and axles are turning. if they are then its hub related. if manual hubs make sure they are engaged,if automatics pull apart hubs and clean and re-grease, if air,start at actuator on axle and follow lines to hubs and then to actuator under hood,sometimes they are on fender wall or on fire wall. make sure lines are good. they are bad about dry rot. make sure actuators are engaging.if they are the cause its cheaper and easier to just convert to manual hubs and be done with it.

kstruckcountry · January 31, 2014

His are automatic. On my 1990 if the front axle was engaged the front end would light up on the transfer case shifter. So if it isn't lit up, even if your transfer case is engaged the front axle won't function.

94sierra16 · January 31, 2014

Ok it isnt lighting up

So, could it be a plug undone? Or is it more complicated?

kstruckcountry · January 31, 2014

The actuator or lines to the front axle are probably messed up. I had trouble with it on my 1990. You have to go though and see what's broken or not working. On our Dodge work truck we just replaced it with a cable that you pull manually separate from the transfer case. I'll dig and see if I can get info again.

Squirrely · January 31, 2014

You have an actuator on your front diff that is probably bad.

https://www.google.com/#q=95+chevy+front+differential+actuator

These trucks don't have front hubs like In the old days. You have CV half shafts that always spin. The actuator in the differential engages your 4wd, not the hubs.

There are a ton of threads on here that go over this problem.

Check the search button. I've seen pics posted, explanations, fixes, everything.

94sierra16 · February 3, 2014

Well checked it today and front driveshaft is spinning so gonna check wires and plugs under it tomorrow

kstruckcountry · February 3, 2014

Whether or not the driveshaft is turning while the truck is on the ground doesn't tell you what the problem is. Front axle not working, transfer case will turn the driveshaft. Transfer case not working, front axle will turn the driveshaft.

You need to put the truck on stands and test it to know.

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