I'm having trouble figuring this one out.

When I have the Blazer running while stopped, there is a loud rattling sound coming from below. I thought it was something on the exhaust, but after crawling under it I'm pretty sure its coming from the transfer case. Imagine putting a couple of bolts in a kettle and vibrating the kettle, then you'll get a good idea what I'm hearing.

The sound goes away when I'm rolling down the road; I can only hear it when I pull to a stop. I have to be rolling very slow to hear it while rolling, and it mainly happens at a complete stop while idling. Today I changed the fluid in the transfer case and it made no difference.

Any idea what the problem might be? I suspect a problem with the chain being stretched, rattling against the case when its not being rotated. Come to think of it, I'm going to try shifting it into 4WD to see if it makes the rattle go away.

If the problem is the chain, is there possible ill effects to driving it this way for a while in 2WD? I don't need 4WD for a while, but I was planning an 8-hour trip to Myrtle Beach next week and I don't want to get stranded on the way. It drives fine otherwise; it just makes that obnoxious racket when stopped.

 

Well, the good news is that I found the rattle. Somehow the heat shield on top of the catalytic converter has gotten loose, so I'll have to find some way to snug that down. It sits directly beside the transfer case, so from the driver side it sounds exactly like its coming from the transfer case. Either way, my TC got an oil change out of the deal.

Right after I found that out, I took it down the interstate for a trip out of town. When I got back, it started bogging down and dying. The fuel gauge showed about a quarter of a tank, but every time I started it back up the gauge would end up somewhere else (usually around the half-tank mark). After sputtering and coasting along for a while, I was finally able to reach a gas station and filled it up. Its not caused me any more trouble yet, but it didn't seem to cost as much as it usually does to fill it to the top (though that could be gas prices). I was kind of in a panic, so I didn't think to look at how many gallons it held.

I never got a fuel light or check engine light. So much for my trip to Myrtle Beach.