front driveshaft/diff question

[rkymtnman]

....and a potentially stupid one at that but since that has never stopped me before....

Front of the '98 is in the air on jack stands - wheels off. We swapped everything up front from our '99. J-shift transfer case, front diff, axles, suspension...you get the picture. So the entire drive train is from a '99.

With the front end in the air, if you spin one tire, should the other spin as well?

also - If you spin the front drive shaft, should the front tires move at all?

Transfer case is in 4H, manual transmission should be in neutral. Still putting this all back together and we were wondering what the behavior should be.

 

[thecole1098]

If it's in 4HI, then the front diff is connected, so yes spinning the DS will spin the tires in the front.

 

[RonJR]

Depends if the ADD is locked or not. If the engine hasn't been running, it doesn't matter what position the transfer case is in, because until you get vacuum from a running engine, the ADD isn't going to lock in. If the ADD is unlocked, the front wheels are essentially connected to nothing. The spider gears inside the diff just spin and nothing comes out.

 

[rkymtnman]

Depends if the ADD is locked or not. If the engine hasn't been running, it doesn't matter what position the transfer case is in, because until you get vacuum from a running engine, the ADD isn't going to lock in. If the ADD is unlocked, the front wheels are essentially connected to nothing. The spider gears inside the diff just spin and nothing comes out.

That is what I was hoping....motor hasn't been run in 6 months...parts swapped in to this '98 over the past month.

Was starting to sweat a bit....and I didn't really understand the ADD system.

 

[alumarine]

If you have a hand vacuum pump you should be able to activate the front diff.

https://www.harborfreight.com/brake-bleeder-and-vacuum-pump-kit-63391.html

 

[rkymtnman]

Thanks....looks like we'll be able to FINALLY turn the key on this beast tomorrow after nearly 5 months of building so with some luck, we can test it for real.