NP246 - always spinning front shaft?

[mitchellbk]

When I was trying to narrow down where the source of a whine was coming from, I was confused as to why the front drive shaft was spinning even in 2WD? I confirmed this with rear wheels off ground in 2WD, and slowly driving truck in 2WD and looking at front drive shaft. Both scenarios spun the shaft.

From what I've read, my 2001 Suburban - this is normal. But I still have questions, and these all pertain to when in 2WD mode only, not AUTO 4W.

- What actually drives the front shaft? In my scenarios it seems the transfer case was driving the front shaft
- When did GM vehicles not engage front shaft all the time? 2006+?


link: http://www.atraonline.com/gears/2006/2006-07/2006_07_10.pdf - this seems to be the best breakdown of the NP246 I've found online. I wish I would have found this way long ago.

 

[littleblazer]

I was under the assumption it didn't spin unless the front wheels were spinning. I've never noticed.

 

[Sparky]

The case may not have the shaft engaged, but simply the front driver side wheel spinning will result in the shaft spinning as well.