No drive in 2H or 4H - Transfer Case Problem?

[fishnchipsx2]

Hi,

Had a loud clunk while driving down the highway in my 1993 GMC Sierra in 2wd, and lost all drive. Can still feel the tranny shifting in and out of gear, but there's no drive to the wheels - except in 4L, which seems to work fine (albeit with some whirring!)

I'm suspecting transfer case, can anyone confirm this before I pull it? Linkage seems to be fine with a positive shift, although it does sometimes take some grinding and effort to get it into 4H and 2H. No visual signs of leaking fluid.

Thanks in advance!

 

[txmnjim]

i'll be interested in this. i've been hearing a clunk when taking off from a dead stop...

 

[fishnchipsx2]

Any more insight from anyone?

 

[fishnchipsx2]

Bump... I finally just got round the dropping the transfer case fluid today - but it's come out nice and clean with no metal debris in there at all. Should I take the risk and purchase a replacement transfer case, or could the problem possibly be something else?

 

[98trck]

which transmission does the truck have?

 

[fishnchipsx2]

5.7 auto, if you want me to be more specific then I'll have to go take a look

 

[Offroadnt]

That is real interesting, just rebuilt a couple, trying to think what could cause that. The only thing that comes to mind is high/low shift collar or fork has failed. What kind of shifter do you have? You should check the linkage on the floor shifter or remove the shifter motor and use a Cresent wrench to rotate the shift actuator and try it.

I wouldn't get a rebuilt, these are easy to fix and chances are the problem is quite simple and cheap. If you are unsure yourself and you have a friend that's mechanically inclined I say go ahead and remove it and take it apart, you have nothing to loose.