2004 suburban transfer case noise

[erockinraleigh]

My transfer case is making a knocking noise after driving in the mountains. It still runs, is it possible to drive three easy highway hours home like this?

 

[zora]

Not sure how anyone can answer that question for you without knowing what is starting to go.

 

[erockinraleigh]

Not sure how anyone can answer that question for you without knowing what is starting to go.

Yeah, it was a shot in the dark for sure. Left out an hour and half ago and it was doing fine, the noise even went completely away. When I first heard it, it reminded me of the sound of a bad catalytic converter, but it just sounded like it was coming from the transfer case. Now, an hour and a half down the road the check engine light starts flashing. Within a few miles I started losing power. Pulled off for breakfast and I'm kinda at a loss...

 

[zora]

without scan tool to check the code only thing you can do is let it cool off for at least an hour and then try driving again.

 

[erockinraleigh]

Thanks so much for the replies. The truck made it home and about half way the check engine light came on. I put it on a code reader and it came back with p101 MAF circuit performance, PO 300 random misfire and 420 bank 1 catalyst efficiency below threshold.

When I first heard the sound my thought was the catalytic converter has gone out, but it sounded like it was coming from the transfer case. I feel a little dumb now...

This is a traveling work vehicle for our band, Urban Soil, and we need it again this weekend. The cat is an expensive repair that I can't get done before then, if I could clean the MAF and get that code to clear do you think it is safe to drive it on another heavily loaded three hour trip, pulling a trailer? Its in the coastal plain and flat this time, no mountains...

 

[zora]

on the P0101 check for something disconnected/cracked causing a vacuum leak
http://www.obd-codes.com/p0101
The other two codes could be caused by the first one, it may not be a bad cat.
If there are no actual mechanical problems and the vehicle seems to run OK you should make it, good luck.

 

[erockinraleigh]

Could that explain the intermittent noise from the cat? I really appreciate the advice!

 

[zora]

that could be the misfire you are hearing, hopefully it hasnt damaged the cat. Do you live in a state with annual emission tests?

 

[erockinraleigh]

Yes, we're in NC so I need working cats and no check engine lights at inspection time. I have some breathing room on that though, I just want to make sure I'm not doing more damage.