99 Yukon transfer case problem

[Dryfly]

My 2wd/4wd dash switch works but when it goes in 4wd it makes a loud banging (whack whack whack) noise. Seems fine when I go back to 2wd. The banging used to be only sometimes. Now it's every time and as soon as I begin moving after switching to 4wd.
I've gotten two different opinions form two mechanics. One thinks motor, the other thinks chain within the TC. How do I know if the problem is the TC actuator motor or the TC itself. Also, if it is the TC itself, am I better having a local transmission shop rebuild it or put in a used one. I can turn a wrench but to have a shop nor any experience with a job like this..

Any help is appreciated..

 

[SunlitComet]

Is this into 4hi or 4 low?

 

[kcb37]

Can you change a u-joint?

Really not to involved.
Take the driveshafts down, disconnect the shift linkage, vent, any wires.
Then just unbolt it from the trans. It will pull straight back and off.

Then put the new on.

 

[1998Suburban]

NVG 241 (3 button) or 246 (4 button with Auto 4WD)? On the 246 you can pull the encoder motor and try rotating the control lever actuator with a 14MM wrench. There are 3 detents on the lever and a spring loaded plunger in the case. If it won't shift manually your problem is inside.

 

[Dryfly]

Is this into 4hi or 4 low?

It bangs in both 4hi and 4lo. Seems to be more severe in lo.

---------- Post added at 11:09 PM ---------- Previous post was at 11:02 PM ----------

NVG 241 (3 button) or 246 (4 button with Auto 4WD)? On the 246 you can pull the encoder motor and try rotating the control lever actuator with a 14MM wrench. There are 3 detents on the lever and a spring loaded plunger in the case. If it won't shift manually your problem is inside.

It's the 4 button (w/ auto 4wd). Since this is my hunting wagon and the season is over, I won't need 4wd until it warms up a bit. (this will be a driveway job). Am I risking much by driving in 2wd until I can give it a go? BTW, although it banks and klanks, 4wd hi does work. I found that out when I was stuck in snow and had no choice but to give it a try.

 

[SunlitComet]

Well the t-case will have to come out and be torn down for inspection. It does sound like it is something in the mode gearing or chain.

 

[Dryfly]

Thanks for the help guys. You've convinced me that I can get the TC out myself. Is the rebuild a tricky job where i should I bring it to the shop to have them do it? I realize that you can't really answer that since you don't know my abilities. I'm trying to get a sense of how much of a job that the rebuild is. The Haynes book only discusses the NVG 241 and clealy states that other model do not apply to the 241 instructions.

 

[SunlitComet]

243 just changes the outside shift mechanism from manual to electric so only difference should be manual linkage to electric motor on the outside and the shaft it mounts to. Otherwise identical. Tranny shops can do them too.

 

[1998Suburban]

I just finished rebuilding the 246 (4 button with auto 4WD) in my Suburban and I wouldn't call the transfer case rebuild tricky. It is time consuming and you have to be meticulous and methodical but it's doable. You'll need the J-44295 Kent-Moore clutch pack setup tool (I now own one) but a trans shop or dealer might be able to tell you the correct shim needed for a nominal fee.
If you're not sure whether to proceed with the rebuild yourself I'd recommend picking up a donor that you can tear down. It sounds like you'll need a fair amount of hard parts for the case anyway. Worst case scenario is that you can bring the junkyard case to the rebuilder so he can scavenge parts from it.

If you want complete step-by-step instructions I used these:
http://www.justanswer.com/chevy/1lzi8-1999-chevy-tahoe-question-transfer-case-when.html

 

[Dryfly]

In looking on the web for rebuild kits, I'm seeing lots of reference to "NP 246" but not a whole lot to "NVG 246". Is there a difference? Same with used TCs as well as rebuilds. Am I missing a point he?

---------- Post added at 09:12 AM ---------- Previous post was at 09:09 AM ----------

Forgot to mention. I haven't looked underneath the vehicle yet to see what the tag says on the TC. There's a bunch of snow and ice on the groung right now. I'd rather wait til I can do that on dry ground. There are 4 buttons as posted above though.

---------- Post added at 09:15 AM ---------- Previous post was at 09:12 AM ----------

It bangs in both 4hi and 4lo. Seems to be more severe in lo.

---------- Post added at 11:09 PM ---------- Previous post was at 11:02 PM ----------



... Since this is my hunting wagon and the season is over, I won't need 4wd until it warms up a bit. (this will be a driveway job). Am I risking much by driving in 2wd until I can give it a go? BTW, although it banks and klanks, 4wd hi does work. I found that out when I was stuck in snow and had no choice but to give it a try.

Any thoughts on my driving this in 2wd until I get the TC repaired?