Rattling sound

[DougG]

I'm getting a rattling sound while driving my 88 RRC. It seems to happen once the truck is warmed up. I checked things under the truck, and the only thing I could find that would reproduce the sound was when I banged on the left catalytic converter. There was something loose in there. The puzzling thing is that the I can't reproduce the sound with the truck in park, and reving the engine. I get the sound only while driving. I checked the ATF fluid, and it looks very clean. Thanks for any advice.

 

[lforgue8]

I'm getting a rattling sound while driving my 88 RRC. It seems to happen once the truck is warmed up. I checked things under the truck, and the only thing I could find that would reproduce the sound was when I banged on the left catalytic converter. There was something loose in there. The puzzling thing is that the I can't reproduce the sound with the truck in park, and reving the engine. I get the sound only while driving. I checked the ATF fluid, and it looks very clean. Thanks for any advice.

SOUNDS TO ME ITS A CAT OR MAYBE A HEATSHIELD IF ITS FACTORY CAT

 

[kalahari]

I went by the local muffler shop today to get a quote on new CATs. Mine have gotten pretty bad over the last month. However I can hear mine rattle while in park.

 

[Landrovernick]

I too have this issue on my 89 classic and thought the same thing. It would make this rattling sound but only when the vehicle was driven and it would lean to the left. Once the rover would straighten up or stop the sound would stop. I had the exhaust changed out with new cats etc. and it still wouldn't stop. To this day I haven't been able to diagnose it and no one seems to be able to find anything wrong. If you do find the culprit (other than the cats) please let me know. Maybe mine has the same issue.

 

[rover4x4]

id just have the cats taken out of the system.

 

[az_max]

check your motor mounts and trans mount. When the truck is in gear, it torques the motor over. It could be hitting something only when in gear because the mounts are worn. It's hard to safely check, but put it in gear with the brakes and handbrake applied and have someone outside locate the general area of the rattle.

 

[DougG]

It seems to follow along with the RPM's. If I let off of the gas, the sound goes away. Once I accelerate, the sound comes. The faster I go, the the faster the rattling goes. As I slow down, the rattling decreases in frequency. I'll have to do more investigating.

 

[lforgue8]

It seems to follow along with the RPM's. If I let off of the gas, the sound goes away. Once I accelerate, the sound comes. The faster I go, the the faster the rattling goes. As I slow down, the rattling decreases in frequency. I'll have to do more investigating.

could be torque convertor bolts loose....take down the access plate and chk the bolts..........also loosen then retighten, maybe even some loctite

 

[kalahari]

I got my 88 back from the shop yesterday and what a difference getting rid of those old CATs made. I removed the front 2 and replaced the 3rd with a higher flow unit. I might actually be able to go through a drive thru and be heard!

This allowed me to pinpoint the "other" rattle coming from the rear. Part of the problem was the exhaust hanger in the tire well was a bit loose causing the pipe to bang around under certain loads...usually ~ 20 mph. Tightened that up and also noticed the rear corner of the muffler was VERY close to the outside nut for the missing mud flap. I suspect that it probably hits it at some point. A good push with the foot gave me a little more room. These two items got rid of most of the issue, but I still have an exhaust noise.

If I put it in gear, step on the brake and rev to ~ 600-700 rpms I have a noise that I think is the muffler. I have no idea how old it is, so I'm running back to the shop at lunch to have them listen.

Edit * As I expected, loose baffles in the muffler. Time for a new one.

Edit 2 * - Wow, what a difference, no golf balls in coffee can sounds, no baffles in the muffler rattling....With he new muffler this thing actually sounds like it has a pair!