whichever it originally came with. the locking was not so common.
No. The pinion seal would be at the differential input.
The actuator on the front differential may not be engaging to lock in the front axle. How can I fix it?
It's better than front wheel drive and even better if there is limited slip and very good if it has a mid differential lock. Manufactures have stopped installing differential locks because the drivers were activating them while a wheel was spinning and thus the splines would shear off the locking mechanism and render any 4wd useless.
It normally would have a 4wd written on the vehicle somewhere. To be sure just look under the front. If you see a differential it is 4wd. If no differential then it is not.
front differential turns all the time
The only place you would use gear oil is in the rear differential and or front differential if it is a 4+4. The differentials have a fill plug.
I'm sure one with the right tools could fabricate it to work.... But for the general, the answer would be NO. The front is a different type of gear system. It also used different axles and mounts differently.
The front axle on these trucks have a mechanical actuator that locks the front differential in. They have used vacuum, thermal and mechanical means for this. The mechanical is the most reliable. This is a common fail point on the Chevys/GMCs. It is located on the front axle next to the differential.
Check the vacum control unit located under the battery. Hook a vacum gage to the unit and see if it will engage if not relace unit. If it does engage trace vacum lines back to source.
my 1989 Chevy 4x4 front differential wont engage any idea on how to trouble shoot the solenoid on the front pumpkin would be great
The only seals on the driveshaft itself would be on the slip yoke. You're probably thinking of the pinion seal, which is at the front of the differential, behind the input yoke to the differential.