Are all 80's this loud (1 Viewer)

[ElPolloBlanco]

I had to do some Highway driving today and noticed that my 80 is REALLY REALLY loud. I downloaded a db meter app on my phone (not an exact science I'm sure) and it peaked out at 92 db several times and hung out at 75-80 db. I'm going to pick up a dedicated db meter from an audio/music store and test it again but that seams really loud to me. I found a link to this site over at the 60's forum and it seems interesting. I'm just wondering if any of you have taken any pre and post deadening test. The Fatmat way seems ok but after reading this site I think I might have better results with the combination of matting, foam, and vinyl provided I have room to lay all of that down under the carpet. I'll try to get a recording of the sounds tomorrow but there's a loud high pitched hum over 30 mph when I'm in the gas. If goes away when I hit a bump or let off the gas but immediately returns. It gets really loud after 60 or 65 and is unbearable at 75-80(average CA99 Speeds).

 

[Rallyroo]

Perhaps your 80 has a hole or crack in the exhaust?

My 80 is nice and quiet.

 

[BrotherRob]

With the stock exhaust, they are very quiet (other than the whistle). If you're getting a lot of noise, you either have an exhaust problem or an aftermarket exhaust.

 

[FunkLord]

What kind of tires do you have? My rig came with a fart pipe at the end, and the super swampers will drown it out at highway speeds.

 

[ElPolloBlanco]

I have some dunlop Fierce ATs but I can't hear them over this. If it was the tires it would be constant. The only time it goes away is when I hit a bump or let off the gas. It's hard to find where it's coming from too. Makes me think it's somewhere in the drive train or exhaust. It's almost like a vibration or something. It's really strange and super annoying. I'm going to go out in the country tomorrow and record a 0-80 run and post it so everyone can hear what I'm talking about.

 

[aroscow]

Might check your uj's as source of vibration.

And isnt there a grommet that can fail where steering comes through firewall, that would let noisethrough too.

 

[RWD]

I had some front wheel bearings that were bad and would groan at certain speeds or while coasting.

 

[darwink1]

Check all the heat shields especially around the cats. If one of them is resting on the exhaust itll be noisy. Would explain the noise going away after a bump too. Get under there and shake the crap out of the exhaust.

D

 

[ElPolloBlanco]

So I took the video this morning. When I got back I crawled under the truck and checked out the exhaust, It looked ok except where it's resting in the frame crossmember that is just forward and above the rear axle. I can see that its come away from the mount. I'm not sure that this is the cause of the noise but I'll need to get it fixed anyway. So here's the video, It's hard to hear on my dinky laptop speakers but at 30 mph you can kind of hear the sound begin then it doubles or triples in volume at 55 and gets progressively louder through 70.

0-70 run in the FZJ

 

[Gumby94]

It doesn't sound like exhaust. Hmmmmm

Sent from my iPhone using IH8MUD

 

[toyota68]

sounds like rear pinion bearing on rear end going bad

 

[darwink1]

The exhaust note would change a little when the tranny shifted no? Seemed kind of constant. For the hell of it tighten the exhaust to the xmember with a gear clamp or something then redo the test. It could be that at a specific speed it vibrates like crazy?? Eliminate that and if its still doing it maybe look into the diff...

D

 

[Brunt Force Trauma]

The exhaust note would change a little when the tranny shifted no? Seemed kind of constant. For the hell of it tighten the exhaust to the xmember with a gear clamp or something then redo the test. It could be that at a specific speed it vibrates like crazy?? Eliminate that and if its still doing it maybe look into the diff...

D

I agree. Exhaust would change with gear shifts. That seems to be something else.

 

[ElPolloBlanco]

I'll try to do that. I actually thought about just tack welding the exhaust back to the bracket that it belongs on and go from there. It's just something I noticed today. I don't think that the pipe sitting on the xmember would cause it to ring light that, then again I'm not sure how much the frame vibrates right there. I'll do what ever it takes to figure this out because it almost makes me not want to drive, ever.

 

[Kernal]

My truck has the same sound, comes on under load after driving a mile or so from a cold start. If the air temp is really cold it takes an extra mile or so to start (diff heating up I figure). Howl starts around 10mph continues up to around 40 mph, almost goes completely away then comes back at 50 mph and continues, the faster I go the louder it gets after that. Determined it was coming from the rear 3rd member by removing the front driveshaft, no change, added heavier weight gear oil to the rear 3rd, sound became slightly muffled, then added a gear oil Moly additive, very slight change again. A few experts I talked to about my truck said most likely the pinion bearings are worn which causes them to lose their preload then the ring and pinion no longer mesh correctly which in turn causes the howl.

 

[ngrich99]

once your up to speed, pulse the gas in a nice fashion, probably diff noise on accel and will go away on decel.

 

[ElPolloBlanco]

My truck has the same sound, comes on under load after driving a mile or so from a cold start. If the air temp is really cold it takes an extra mile or so to start (diff heating up I figure). Howl starts around 10mph continues up to around 40 mph, almost goes completely away then comes back at 50 mph and continues, the faster I go the louder it gets after that. Determined it was coming from the rear 3rd member by removing the front driveshaft, no change, added heavier weight gear oil to the rear 3rd, sound became slightly muffled, then added a gear oil Moly additive, very slight change again. A few experts I talked to about my truck said most likely the pinion bearings are worn which causes them to lose their preload then the ring and pinion no longer mesh correctly which in turn causes the howl.

So is that an easy fix?

 

[Kernal]

Easy depends on tools and skills; haven't replaced mine yet but it will require the 3rd member to be rebuilt or replaced with a known good unit. Wait for some experts to chime in and maybe do some checks to narrow down the cause of your noise. Here's a link with a lot of information about rebuilding differentials:

http://www.gearinstalls.com/

 

[wasilvers]

sounds like rear pinion bearing on rear end going bad

saw your video and looked you up here. I agree with this guy. It can sound like wind noise or tires, till you take your foot off the gas. I tested this on my ford truck and pulled one of the driveshafts. You can figure out which one it is coming from this way. I figured out it was my rear diff. I had it replaced ($1800 shop prices), then that suffered catastrophic failure in 6mo, so I had it rebuilt ($800) - much better option and worked awesome. I had it rebuilt to a limited slip.

Good luck,
Will

 

[ToyotaDon]

I may be able to let you use a ChassisEar to pinpoint the noise.