Troubleshooting noise, possibly rear bearings?

This is a 2004 4Runner SR5 2WD, 180K. I have fixed pretty much everything its just this noise is bugging me. Wish I could explain it, but sounds like a faint grind that starts at 25MPH and up to 50MPH I can hear it, then the other noises I think take over but pretty sure its still there. Do not feel it in the steering wheel, and I have also replaced both front bearings already.

What I did notice is if I turn sharp right, the noise just about disappears, sharp left turn it goes louder. I did lift the rear end today and I cannot feel any movement, up/down, on ether wheel and used a stethoscope but cannot hear any grinding or I am just not doing it correctly, which is more likely.

I did change the diff fluid, as it was due anyway, that did not make it better or worse... was not expecting it but just a comment.

From what I can tell, it is the rear right bearing going out (due to it getting louder when turning left, and quieter when turning right), however was at least hoping to feel something when checking things out. I understand since its a solid axle the bearing movement will be minimal unless I take the shaft out but wanted to get the internet's opinion on this.

I can get a complete shaft (Doorman, not crazy about them but only ones that make it) and its quite expensive to just throw parts at it. I do not have a press or the Toyota bearing puller thingy, which is why the complete thing is enticing.

$387 Dorman 926-142 Rear Passenger Side Pre-Pressed Rear Axle Compatible with Select Lexus / Toyota Models (OE FIX)

https://www.amazon.com/dp/B08FS2K3QS/?coliid=I2T0UF2RUYDG8R&colid=IC0RV688W4O

 

Possibly a wheel bearing going out. You don't need to buy a new axle shaft since there's nothing wrong with yours, it just needs a new bearing. Find a local repair shop that will replace the bearing on your shaft if you pull it and bring it to them. Save you some money in labor that way.

 

To update everyone... while I had to car in for an alignment at a local independent shop I trust asked them to look at the noise... after they test drove it, put it on the lift and did some diag they told me that the rear differential needs to be replaced. Apparently the noise is coming from the differential itself however they did not open it to get a close look as it was close to end of day, but he was pretty sure it needed a new diff. He quoted me $2500 including a new axle, diff and the labor to replace it however I want to do this on a budget. Reading up seems East Coast Gear Supply seems to be the one to go with so I am going to email them see what kind of price we are talking about for a new diff. Never replaced the diff, however seems take axles out, drop the driveshaft, some swearing trying to get stuck bolts out, take way too much time finding dropped tools etc. Not sure yet which way I will go, however will see what ECGS has to say.

 

I just swapped out my 2018 rear diff with a 2020 rear diff....pretty simple DIY project. Found the 2020 diff from salvaged parts rig off a local T4R enthusiast. I'm sure a 2004 would be similar...check youtube for details.

 

Depends on how much you want to spend on a 20 year-old vehicle. Can also look on Car-part.com for a salvage yard complete axle assembly.

 

I am not against spending money on this 4Runner, I bought it for $500 from a coworker (with known issues, this being one of them) knowing I will have to spend money fixing it. I just want to make sure I am spending the money smartly and for some reason I am just not convinced the diff (or more likely the pinion bearing) is bad.

 

I would bet it’s the passenger rear bearing based on what you’ve said about the noise getting quieter when turning to the right.

I just had a bad rear bearing on the driver side and it would go quiet when turning to the left. Other than that mine was a low pitched hum/roar that was most audible between 30-55mph. Another sign that this was the problem side was the axle seal was leaking gear oil all over everything. You might check and see what yours looks like underneath and around the brake rotor/backing plate

after replacing mine, it’s nice and quiet again. Once the axle is removed, you can spin the backing plate/bearing assembly and if it doesn’t spin smoothly or has a gritty noise like mine, then that’s your issue

 

Exact same symptom as mine, above 55-60mph it starts to quiet down. No gear oil leak, I had the brake caliper and rotor off and found nothing in the leakage department.
My plan is to this weekend (hopefully) try and slide the axle out as much as I can without removing the drum parking brake assembly... I do not like working on drums lol.

 

lol I’m with you there, brakes are my least favorite thing. I had to buy a special tool to reassemble the parking brake drum springs. There are a lot of moving pieces in there. Keep us posted on what you find

 

Is there a link you can share for a drum brake tool kit? Or did you peace it together youself.

 

here’s the tool I bought for the springs/retainers for the parking drum shoes. Other than this, I used some big needle nose pliers, a couple different metal picks, and a large flat head screwdriver to wrangle the large springs back into place.

JTC Tools 4487-Rear Handbrake Spring Driver-Compatible with Toyota

https://www.amazon.com/gp/aw/d/B076YMRND3?ref=ppx_pop_mob_b_asin_title

this video is good for reassembly on the parking brake shoes
https://m.youtube.com/watch?v=I8MqhrZ9MD0

 

Had a chance to do some digging today... basically slid the whole axle out (without taking off the brake assembly or parking brake stuff) just so I can isolate the axle. To my surprise, there was a little bit of gear oil leaking (very small amount as far as I can tell), the dust shield or axle seal, whatever the correct term is, is in pretty bad condition and there was some what looked like reddish grease... I was worried for a second as there was no play in the bearing, but as soon as I started to rotate the dust shield back and forth, as much as the parking brake cable would allow, it felt very gritty and not smooth at all. I am basically convinced the passenger rear wheel/axle bearing is shot.

Now the dilemma... Looks simple enough for a DIY job, however I do not have the bearing pulling adapter for a Toyota or a 20T press that is on a H-frame. I could get both of these for under $300, plus the bearing (I am partial to Koyo) for about $550. Around where I live (Farmersville, TX) I went to a few independent shops and asked them if I brought them the axle shaft and the bearing if they would press the old one out and the new one in, but all said nope, not a Toyota. Anyone know of any mechanics in the Dallas, TX area that will do this job if I bring them the axle? Not sure who much they charge but anything around the mark of buying the tool and press would be a no brainer for me.

Thanks!

 

Well, found a shop in Denton, TX that is willing to press the bearing out and press a new one in if I bring them the axle shaft. Took the passenger side off, and while I am not a trained mechanic, I think this bearing has done its duty.

 

First things first... drum brakes are the work of a devil .
Now that out of the way, yesterday picked up the axle shaft with the new bearing pressed in from the shop and mounted it on the car... wow what a difference, whisper quiet! This procedure was pretty easy, other than trying to figure out a way to grow a couple of extra hands to help with the drum brake assembly, but it is all worth it. $350 parts and labor for the bearing to be pressed in, new retainer and new seals.

Now on to look for OEM Headlights to replace the crud ones the PO put in from eBay.

 

^Drum service brakes like on prev-gen Tacomas are high-maintenance if you go off-road, but aren't difficult to service, because the shoes extend beyond the hub flange outline. The 4Runner's in-hat parking brake is next-level hentai tentacle rape evil. Good thing that's going away in 6th gen.

Oh and the JTC tool works only on OEM Toyota cup washers. Aftermarket cup washers from the widely available parking brake hardware kits have a different emboss pattern and don't fit the prongs on the tool.