The Elusive Front Dash Rattle...
 

I can't seem to find where it's coming from. Could be in the dash, behind the dash, or even in the engine bay right next to the firewall. I just replaced heater core and ac evaporator, and they seemed nice & snug when I put them back in - but the rattle is right in that general area. I'm dreading taking out the dash again and hoping someone might have an idea :(. It's a long shot, but any guesses would be appreciated.

I have so many dang rattles in that area. I just turn up the subwoofer and drown it out

X2 Yeah your gonna go crazy trying to find the rattles. Your time would probably be better spent installing a good stereo. This method worked for me. If you can't hear it there's nothing wrong! :)

It is extremely common to have dash rattles after replacing the heater core, because of everything that has to be torn apart.

Dash rattles can be a real bear to isolate. I've got some pieces of different thickness of industrial foam from my previous employment which I use for stuffing in the gaps to help with rattles.

I'd start with taking a ride and having someone else drive. That leaves you free to press on everything you can get your hands on to see if you can lessen or eliminate the rattle; then you at least know what to concentrate on.

And if you can't find the root cause, as mentioned, might be easier to turn up the tunes than to tear everything apart again. It is very frustrating.

Good luck!

I found that the gap between the center console and lower dash is very minimal; they vibrate each other. That's the only thing I had rattling.

Very good idea having someone else drive. I'll give that a shot.

Good suggestion - I'll check that area.

On my 98 I have this rattle/rumble, especially at an idle that is annoying. Sounds like it is back in the dash, but come to find out that if I lift my transfer case shifter ever so slightly, the noise stops. Have you tried this?

No, But I'll give it a try. Does that mean you drive around pulling up slightly on your shifter?? lol
Mine tends to rattle while I'm in drive, but at a stop - like at a traffic light. If I put it in park, it stops. If I step on the gas, it stops. So damn frustrating.

GM7203 - you are a godsend! Amazingly, the transfer case shifter IS the culprit. If it starts rattling, I just pull it up a little bit, and bingo - no rattle.
Problem solved. Thank you.:)

I had noise on my transfer case shift lever on my 1999 when I bought it new. The noise got much better if I just lifted the transfer case shift lever a little bit.

There was a TSB for it 21-09-98 titled TRANSFER CASE SHIFTING NOISE which involved installing a transfer case shifter repair kit. Part number is 05014148AA. I had the dealer install this TSB under warranty and that took care of it. It doesn't say on the TSB what years it covers, but sure sounds like it could be your issue.

1. Disconnect the shift rods from the torque shaft
2. Remove the torque shaft by prying the shaft out of the green torque shaft bushing in the transmission bracket. Install new bushings on the torque shaft.
3. Remove the bronze bushing/retainer and rubber gasket from the body bracket
4. Remove the green torque shaft bushing from the transmission bracket and install the new bushing supplied in the kit
5. Insert the new gasket into the body bracket
6. Install the bronze bushing/retainer and tighen the screws to 45 in lbs
7. Slide the boot onto the torque shaft and apply multipurpose grease to the area that the bronze bushing will contact
8. Install the torque shaft and seat the boot on the bushing retainer flange
9. Connect the transfer case shift linkage and adjust as necessary.

http://www.quadratec.com has the repair kit.

Item Number Item Desc
52207 0007 SHIFT LINKAGE REPAIR KIT 87-01 NP231 5014148AA

I wouldn't use their plastic bushings though, I had to go to the dealer and get ones that would work, $3 apiece. The ones in the kit are hard plastic and not pliable so the rod ends do not press through as they should and stretch the bushing out until it elongates and pops.

I came up with this after seeing how corroded my linkage was (I didn't want to break anything). It's been working fine for over a month. If you want to try it and need details just re-post.

The kit is at best a 30min fix as long as you do not remove your linkage rods from the torque rod's bushings.

Take the 2 10mm bolts out of the body side bracket, pop the torque rod out of the green bushing that is in the plate mounted to the side of the transfer case, lift the rod end, pull the torque rod out of the body side bracket hole, slide your new brass pivot plate on, slide the new rubber boot on. Then push the rod back into the hole in the body side bracket and press the other end back into the green bushing. Put your 2 bolts back in and you are finished.

It will take you more time taking the two bolts out then the rest of the procedure combined.

Doing it this way, do I still need to get the other bushings from the dealer?

Thanks for the help.

As long as you don't damage any of them then no. If you do don't even bother trying to use the ones in the kit, go to the dealer and get theirs.