Transmission/ t- case question

[Jtaylor28752]

I have a 2002 Yukon 4wd 5.3 i had some issue slipping out of overdrive and not wanting to engage reverse. Drive it that way for months until i could have it rebuilt. Last week it started making a grinding/ whining sound when it changed gears so i parked it had it towed home and messed with it a little bit. When putting it in reverse it would start the whining/ grinding sound without acting like it was engaged but the speedometer was bouncing up and down up to about 15. So after i got all 4 wheels off the ground when in neutral i turn the rear drive shaft and it turns freely but the front one turns also (keeping in mind it's in 2wd mode) the front wheels wouldn't turn just the front driveshaft was under the impression the t- case shouldn't be locked with the front shaft while in 2wd? I don't know I'm going to go ahead and rebuild the transmission since I've known for awhile it needs it, should i go ahead and do the t-case as well or what? The speedometer bouncing is what threw me off since the vss are on the t case
Thanks in advance
Justin

 

[Scottydoggs]

the whole front axle turns, shaft and all when in 2wd. this is because they killed off locking hubs, now you drag that extra rotational weight around all the time.

 

[Chubbs]

The front axles have a disconnect. In 2WD the front differential is technically disengaged but the older, pre-2003 TC has a certain amount of preload on the clutch pack so the front DS will turn the carrier but the front axle shafts are not engaged.

@Jtaylor28752

Try some diff search phrases on Google. There is a lot of literature/threads/discussion about the front DS turning in 2WD, but supposedly only the earlier version of the 246. It went through 2 or 3 design changes. There are forums on other web sites that discuss this. YouTube might have something on it as well.

If you put the wheels back on the ground and lift only 1 front wheel free, you should be able spin that tire & axle free. If the DS is turning, hold it still and see if the diff and axle will turn freely. If that doesn't work, I would pull the front actuator off just for the hell of it and see if that doesn't have the axles locked up.