h0runner

1990 4Runner sr5
22re
5 speed
4wd


Hey yotatech. Pulling my hair out about this rear end squeak that recently became almost constant.

back story- it’s occasionally made this noise for a few years. Mostly a little squeak now and then for a couple wheel revolutions then it would go away, mostly in summer months when it was hot. Would occur maybe once a week and could only hear it with the windows down. Became very loud about a month or two ago, so I figured it was wheel bearings in the rear, jacked up the rear end and both sides had a little play so I changed out both sides in the back along with new up front. All koyo with factory Toyota hardware, except in the rear I used the trailgear upgraded housing side seals from yotamasters.

After doing this I didn’t notice the noise for a little while, figured it was gone. About two weeks ago it came back hard. Almost constantly when I’m going in a straight line. Not really noticeable on the throttle because I have slightly louder than stock exhaust. If I put it in neutral and coast to a stop it’s very loud whether I have the windows down or not. It’s down right embarrassing. This morning I swapped brake shoes and hardware in hopes that was the problem. No dice. It is slightly quieter but still prevalent. It sounds like it switches sides that is louder, driver to passenger, but it’s almost always there. I drove a curvy downhill road so I could be in neutral and record a bit, and I noticed on the tight curves I could not hear the squeak. Also I can not duplicate the sound on jackstands.

relevant info, the rear end has a Eaton trutrac with 4.88 gears in a 3rd gen v6 member. The noise was before I did the diff swap though.

any ideas? Here’s a little video that kinda shows sound even with wind noise. kinda sounds like someone jumping on a squeaky bed lol. Can’t see any evidence of backing plate being bent or contacting drum, or of the wheel rubbing the drum cover.

JoeS

Could it be a bent backing plate rubbing?

h0runner

I can’t see any evidence of that. Only shiny spot on the drum is where the shoes ride.

Jimkola

Drum out of round?
If you adjust the brakes shoes the opposite way, so the shoes don’t touch the drum, does the noise change/diminish/go away?

h0runner

I did try that and the noise didn’t go away. It’s not 100% of the time but it’s most of the time now.

JoeS

Maybe jack the rear up, leave the jack under the diff housing, put jack stands on the axle housing, chock the front wheels rear good, and get someone you trust to sit in the truck to give it gas to spin the wheels to try to isolated the location of the noise. At least that way you know it's not a suspension travel scrapping noise. Maybe download a DB meter app onto your phone to point for noise.

Good luck. I hate any not normal noise.

h0runner

I’ve put it on jackstands and ran it, can’t find the noise. Haven’t had someone else do it and I crawl around with a db meter tho, I can try that. I can’t seem to hear anything unless it’s on the ground though.

h0runner

Update- made sure all points were greased, cleaned real good. I cranked the adjusters all the way in so the shoes were definitely not dragging. Noise still there. Had my wife run it on jackstands and pull he parking brake and tap the brakes while it was in gear, nothing. It will only do it on the ground and when rolling forward in a straight line. Noticeably loud when at lower speeds (25mph or less), mostly when coating in neutral. It sounds like it’s mainly coming from the driver side, though I’ve heard it be louder on the passenger side in the past. Noise DOES NOT change whether I’m on or off the brake.

so far I’ve done:
wheel bearings with Japanese koyo bearings
brake shoes
hardware and springs
greased all contact points and adjusters.
changed diff fluid (thought why not)
cleaned inside of drums with a wire wheel

not really sure what else to try, it’s hard when I can’t duplicate it when it only does it when it’s actually driving.

JoeS

It is a repetitive noise and sounds rotational have you checked the drive shaft?
Does it have a drive shaft center bearing?

h0runner

no driveshaft center bearing

the noise is rotational and repetitive, but its repetition seems too slow to be driveshaft, I shook it this morning before leaving for work and it didn’t have any play other than the little bit of rotation while the pinion spins to engage the ring gear.

I replaced the u joint at the 3rd member flange a couple weeks ago and nothing changed, maybe I should grease the slip yoke and swap the u joint at the tc flange, too. I did replace the tc output shaft seal a while back, but I don’t remember if i did the u joint there at the time. I have a spare moog so I can throw that in there and see. I should chalk mark my tire to see if the frequency matches in the mirror.

JoeS

I thought it was too slow for drive shaft too, but never hurts to check everything that rotates.
What else can be rotating if not axles, differential, tires, and drive shaft.
How about your suspension/shocks are too stiff/worn out and the rear of the truck is slightly bouncing in rhythm with the speed and scrapping?
Shocks slowly wear out over time, so we don't notice them going bad, but do notice the difference when they are replaced
Doesn't have bounce much and scrape on metal to make a noise.
Try going over a speed bump to see if the noise appears?
Just spit balling here.

I hate noise too even road noise. I lined the floorboard, trans tunnel (2 layers), behind door/kick panels, inside fwd bulkhead, and rear cab wall with Frost King closed cell thermal insulation to keep heat out and it also cut the noise down significantly.

h0runner

I appreciate the random suggestions since I’m at wits end with this noise. I’ll definitely grease the slip yoke and swap the UJ at the TC.

as far as suspension components, I’ve tried bouncing on the tailgate the get that sound to happen and it won’t. Shocks have new uniballs on each end (they’re aftermarket SAW 3.0 remote reservoir shocks) and I have tried hitting bumps. The only thing I’ve noticed is that if I turn while the noise is happening and I’m rolling it goes away for the short time I’m in the turn. Once straightened out it comes back. Could he because the wheels are spinning at slightly different speeds for that short amount of time, could he because outside rear has more weight/inside rear has less weight from weight transfer? I’m not sure.

Andy A

Could it be coming from somewhere else than the rear and actually traveling to the rear. Sometimes sound can do some funny things. Just a thought.

h0runner

you have a really good point. I’ll try spinning the front wheels off the ground when I get home from work. It has a manual hub conversion so that eliminates the front driveline and isolates just the hub and brakes up front.

it definitely has that sound of a drum brake though. Have you ever used your parking brake to come to a complete stop? It’s that friction creaking sound right at the instant before you come to a complete stop.

Jimkola

I did ponder parking brake. But is noise on both sides?
Try disconnecting both parking brake cables at the back of the backing plate and driving.
I'm leaning towards something with the brake shoes/drums only because pretty much anywhere else there would be signs of rubbing that would be out of the ordinary (shiny bare metal )
If that goes no where, You might also get a dial indicator that you can mount and check for run out at the drum and axle shaft flange.

h0runner

it changes from one side to the other occasionally. Right now it’s driver side, a week or two ago it was passenger side.

I’ll try disconnecting the parking brake and seeing if that makes a difference. I don’t know if I can do it at the backing plate but I can definitely do it near the fuel tank.

that’s a good next step too is axle shaft runout, though I think if that was the case I’d see rubbing somewhere other than the shoe mating surface inside the drum. I do beat on this thing a bit and it’s been airborne more than a few times so it’s totally possible an axle shaft is bent. How strong are the oem shafts for an 8”? I’ve heard of dudes snapping them crawling but I haven’t seen much as far as just a bent one.

if that’s the case this might give me a reason to convert to a full floating setup or find 4130 shafts…

Jimkola

Well, if the axle flange is bent and not spinning true that would also mean your brake drum is spinning out of round, along with the tire/wheel.
But I'd check drum first. If its not true than check axle flange just to make sure it's not the root source.

h0runner

I can definitely check the flange with a dial indicator, not sure how I’d check the drum for out of round, though. Maybe put them on inside out and run the dial indicator along the inside where the shoes ride?

JoeS

If the axle or flange are bent the wheels would be vibrating.
Do you have a seat of the pants vibration that gets worse as you increase speed?
If not, then I guess nothing is bent or out of round.
From all you have checked I think the sound coming from the front is next to check
Maybe inside the bell housing?

h0runner

No notable vibrations that are consistent or increase with speed, so you’re probably right if the axle shaft was bent enough to be making noise I’d probably have a pretty wicked shimmy going on.

I think if the bell housing was the culprit I’d hear differences in different gears or neutral, it appears to be consistent whether in in gear rolling slow, in gear with clutch pedal in, or in neutral. As long as I’m rolling it can be heard. I did have a weird chirp taking off from the clutch about a year ago after a 700 mile road trip, but that healed itself right before I was about to buy a new clutch. That was in a noticeably different spot than the sound is coming from now.

I keep thinking hubs since it requires wheels on the ground to make the noise, though. Not necessarily load, but weight. If I put it on jackstands and drag the brake I get no noise. It’s something from the output shaft to the hubs I’m pretty sure. Maybe the front wheels, I’ll check that for sure.