4wd issues in 86 B2

[jkufen]

I have an 86 B2 and a few days ago I was trying out the 4wd just playing around on the railroad tracks and I had a few issues. When I was on flat land the 4wd worked fine but when i started climbing the rocks up to the tracks my issues began. I had it in 4H and in first gear as I was on the incline and I let the clutch completely out and I went no where. The truck didnt stall and I wasn't paying attention and as I kept the motor rev up for several minutes it begin to run hot and started smoking with a buring smell. Then after it started smoking it all of sudden took off and off i went. I let the truck rest a while and started it back up and tried the 4wd and it worked fine on flat land. I think I am low and fluid and thats why on inclines it acts up. Any suggestions? Also I need to replace the fluid in the front and rear end any advice on what kind of fluid to use and exacly how to replace the fluid this is my first older model truck and my first 4wd. I have never had to worry about the fluids like this before. Thanks for the help!

 

[4.0B2]

80-90 diff fluid

the rear axle has a fill plug on the front of it, above the pinion on the driver side..just look for a square hole that a 3/8s extension will fit in, take that out... fill it up to that hole with fluid.

the front axle has a fill plug on the front of the diff

if you have limited slip in either axle, you need to add some LSD additive to it (maybe). if you don't know if you have limited slip or not, look in the tech library for how to read the data tags on the rear diff or the door sticker axle codes.

 

[adsm08]

Does it do the same thing in 2wd?

It actually sounds to me like the clutch is slipping when you load it up on a steep incline.

 

[jkufen]

No it rides fine in 2wd itll just spin the tires on an incline. I gonna try the fluid replacement and get everything cleaned up and topped off and see if that helps but this truck has been fighting me since day on so im sure itll be something else.