Front Driveshaft Turns In 2wd

zaac · February 25, 2009

I've read through all the posts and still don't get it. My front driveshaft stays engaged in the TC while in 2wd. The front diff disengages. Now I'm thinking either the clutches are warped/sticking or the tc is designed this way(246). If it's supposed to be this way then why can I hear the tc actuator working when I push the 4wd button? It was already engaged when in 2wd. Those in the know please help and if you don't know please don't confuse me more. Thanks in advance.

zaac · February 26, 2009

I decided to get a little meaner with it and stuck a big screw driver in the yolk for some leverage and the driveshaft turned. Seems it is disengaged like I figured it should be but is dragging a bit. I think I'll get a service manual for it so I can rebuild it when the time comes.

green 788 · February 26, 2009

I don't think that's necessarily out of the ordinary. I've heard several folks mention this, and as far as I know my truck (a 1996 K3500) also does this.

I note also that the PTO shaft on our International road tractor, which runs a petroleum pump, turns when the PTO is disengaged (and the truck is moving forward). This is because of the effect of transmission oil circulating and spinning that shaft. When you accelerate down the highway, the shaft settles down (and also the oil is thinner at this point and not as apt to spin that shaft).

Anyway, I'm pretty certain that you really don't have a problem. Check with some other guys for sure...

Dan

ZZ327 · February 27, 2009

I think its normal.

StoneyPgh · February 27, 2009

I think its normal.

I AGREE.

If the front axle doesn't have lock-out hubs, it seems that the front driveshaft has to turn.

zaac · February 27, 2009

I think it's normal too. I'm gonna save the rebuild for when things get noisy or something breaks. Thanks for the help.

schmittygm · March 1, 2009

the GM 246 transfer case still transfers 40% torque to the front driveshaft even in 2WD. Must be true because i have a '99 chev with a 241 and the front driveshaft doesn't turn but on my '00 with the 246 it turns at all times. i think its just the way they have to be set up for the "auto" function.

Westlotorn · April 28, 2009

SmittyGm is right, this is normal. Seems to work just fine and gas mileage is as good or better than Ford or Dodge.

It is just not what you would expect to find.

BrockwayMT · April 28, 2009

It's probably fine. How do you know it's staying engaged? Are you trying to spin the front prop by hand when the truck is in park? Or are you running it in 2wd up on a lift? Is it cold? The clutches will drag a little from the shearing of the oil. They will drag much less when hot.