Light rattling when accelerating? (1 Viewer)

[corleykj]

I have a 99 lc that sounded great when I bought it a couple months ago. I put 285 75r16 Nitto Terra Graplers and cranked the torsion bars....then came this light rattle or knock or something???? It occurs when I start from a stop, and it sounds like some weird vibration or light knocking? It doesn't last once I get above 10-15.

Any suggestions what this is? I can't figure it out?

Maybe bad shocks vibrating? Maybe engine mounts? I have no idea!!!!!

Thanks in advance!

 

[2000UZJ]

it is RPM or wheel speed related?

 

[corleykj]

it is RPM or wheel speed related?

I don't think it happens faster with wheel spin. I have tried listening for that. So I don't think rpm is related.

It is also weird because I can't tell where it is coming from but It sounds like underneath the cab? But not sure if it is in the front or rear or both?

Kind of sounded like loose center caps on my wheels but I can feel the rattle in the floor board....I think I can feel it, but it is t really hard hitting.

Thanks for any more ideas!

 

[jttexam]

I hate to be the one to even hint at this, but failing catalytic converters rattle upon acceleration when they begin to fail.

Rev the engine with the transmission in neutral. If it rattles accordingly, it is likely the cat. Don't let it go, you will get stranded.

 

[Trunk Monkey]

The shields around the cat are a pretty common mystery rattle.

 

[corleykj]

I haven't heard it rattle when I rev it in the driveway....but that cat sounds more probable than some other things that crossed my mind.

Any tips on securing the cat shield?

 

[2000UZJ]

large hose clamps work. Make sure it isn't a rock or debris trapped in the case of the cat shield.

 

[r3run33]

mine the the heat shield bracket; used the hose clamps no rattle anymore

 

[corleykj]

mine the the heat shield bracket; used the hose clamps no rattle anymore

How large of hose clamps should I buy? I rode to work and don't have my LC here.

 

[Musky]

I have a 99 and had the same thing. It drove me nuts!! It's not the cat shields rattling, at least it wasn't on mine. I went out and bought a bunch of hose clamps and clamped them all over the place
around the cats. The noise was still there. It only did it at certain speeds and under a certain type of load. I had my wife put the car in drive with her foot on the gas and brake to create the rattle while I climbed underneath since I couldn't pinpoint it myself from the drivers seat. It came from the back of my muffler. There is a little flange the connects to the muffler to hold it in place. Mine was rusted apart and was tapping against it, I just bent it out of the way and now it sounds great.

Look at the back of your muffler. It's worth a shot. I'll go and try and take a picture to show you.

 

[corleykj]

Thanks for the tip on the muffler flange thing. I will check that too.

 

[FJCowboy]

Interesting, I just recently discovered a similar issue over the weekend. Mine seems to be when accelerating and putting pressure on the shocks. I believe my is front passenger side. I was thinking shocks or the CAT came to mind as well. I need to do some more testing to pinpoint it better. I will take a look at all of these recommendations as well. Thanks

 

[corleykj]

Interesting, I just recently discovered a similar issue over the weekend. Mine seems to be when accelerating and putting pressure on the shocks. I believe my is front passenger side. I was thinking shocks or the CAT came to mind as well. I need to do some more testing to pinpoint it better. I will take a look at all of these recommendations as well. Thanks

I put new tires and cranked the torsion bars so early on in my purchase of the land cruiser, that I am not sure if it started before or after that. But....I am wondering if the weight distribution with the torsion bars cranked caused the rattle to be intensified. I thought shocks too. I will try to trouble shoot tonight.

 

[corleykj]

Rattle/clanking fixed....with new cv joints!

After 12 months of trying to figure out where this rattle was coming from and trying hose clamps galore on the cat shields, the rattle just kept getting worse. More like a clanking and did get more frequent with wheel spin from 1300-2300 rpm all the time now. A friend drove my cruiser last week and said I need to do cv joints. Well, after one really late night, and that friends help, there is no more clanking or rattling while accelerating. It was cv joints and am I glad I did them. The FAQ section had some great information on working on the CV's which made it possible to do the repair.
Thanks for the tips last year! It is finally fixed.

 

[SALTY METHODS]

I have the same problem. One of those mystery rattles that you tell people about and they think you're crazy. (1st post, yup I'm a lurker)

 

[pavieSD]

I had a mystery rattle in the back, assumed it was shocks or muffler etc. Checked everything underneath, and all was tight. Spent a few months annoyed. Finally one day I was meeting a mud member to pick up some new seats for my FJ40, and he was running late, so I opened up the back and started checking seats, etc. Turns out my rattle was with the jack case in the drive side rear compartment. The rubber strap broke and was letting things bounce around in there when I hit bumps, or had low acceleration. Secured it down nice and tight and no more rattle. Worth a look, and an easy fix.

 

[06bom6]

This is old but i just wanted to thank the previous poster for mentioning the jack location, as that was the cause of my rattle. I just picked up my 100 yesterday and this was driving me nuts lol.

Thanks y’all.

 

[whatsvanos]

my cv’s are new..

i’ve yanked EVERY heat shield off the entire exhaust. i still get this rattle that i can feel barely through the floorboard. the rattle happens only on certain loads and usually around 3k rpm or under hard acceleration. if it’s not exhaust...and not cv’s what the hell could this be. it’s driving me insane it makes me feel like the truck is a piece of s***

 

[whatsvanos]

also mine is a 99

 

[dahlmaker]

also mine is a 99

Did you find the rattle?