145,000. I'll give it a whirl tomorrow. Used a ratchet and funnel on the pulleys i could safely touch. Honestly the alternator was audibly louder than anything else... Which tbh was what i originally thought it was coming from. But no issues with the alternator itself. Autozone said the alternator is sold with the pulley attached--that is that the pulley wasn't sold by itself or able to be replaced. I'm going to do what you suggested and if those things are fine, I think I'll see if i can't explore the alternator pulley more.

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Definitely the alternator. Grabbed a cheap stethoscope and it's quiet on the valve cover and other pulleys but it sings on the alternator. Can that pulley be removed without replacing the entire alternator?

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There is no “pulley” on the alternator, it is just a grooved wheel pressed into the alternator’s shaft and if you have pinpointed that as a source of the noise then what you hear is a bad\ falling bearing (s) in the alternator.

That alternator needs to be replaced or repaired... there are no other way to fix this.

I found the FSM online. It has a clutch pulley that can be removed and troubleshot. Searched for the SSTs (Special Service Tool) needed: the wrench is $500 and the puller set is $1400. What a joke! Going to try to find a workable universal set and might do a write up if I can.

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I'm not 100% certain you have a clutch pulley on your alternator. The manual shows a clutch pulley, however, that particular part appears to be a simple pulley when I look up the part for my 2011 Trail: 2009-2020 Toyota Alternator Pulley 27415-0W131 | Camelback Toyota Parts See this discussion Alternator output? One YouTube video appears to show a simple pulley, but that could have been an aftermarket alternator. Have you verified you have a clutch pulley? Given the price $82.34, it should be a clutch pulley.

If you need a clutch pulley tool, Malcolm put up a positive review on this tool set Amazon.com: Customer reviews: Gates 91024 Alternator Decoupler Pulley Tool Kit with Case after Gates replaced one of the wrenches that broke on the first attempt to disassemble. Gates has an excellent video on diagnosis and repair using their tool set: GATES TRAINING: Alternator Decoupler Pulley - How to Inspect and Replace (full version) - YouTube

If you have a clutch pulley, have you attempted to test it with the alternator on the vehicle? Remove the belt and rotate pulley back and forth to test it. You might have to hold a small screwdriver against a cooling fin to keep the core from rotating. If the clutch pulley failed and the alternator bearing is OK, Gates recommends replacing the serpentine belt, tensioner and clutch pulley at the same time. Your belt and tensioner might be OK if the problem is fixed soon enough to avoid exposing those parts to excessive torsional vibrations.

Wow… learned something new here… sorry for misleading\wrong info…. And yes “$500 wrench and puller set for $1400” is absolutely crazy… keep us posted and thank you for the info and feedback.

Why not just get new OEM alternator since it sells for less than $300 at the dealer?

I checked Camelback Toyota Parts. A 100 amp alternator (PN 27060-31260) for my 2011 Trail is sold without a pulley for $279.44 and the pulley (PN 27415-0W131) costs $82.34 ... I don't see an option to buy both assembled and ready to install. A DIYer still has to use tools to disassemble/reassemble if they want to get parts from the dealer. Alternator for 2011 Toyota 4Runner | Camelback Toyota Parts It's a 1.5 hour job for an experienced mechanic to remove and replace the alternator.

If you are going to replace alternator Upgrade to OEM Toyota 130 Amp one (part #27060-31190)
Search Results | Conicelli Toyota of Conshohock

You're 100% right. Either i don't have a clutch pulley or it's 100% defective, bc it spins freely in either direction.

Did the rent a tool at AutoZone for their decoupler pulley tool kit. Of course it didn't fit. It's annoying that the FSM just shows the SST number and not a size bc no one stocks the removal tools locally to manually size it!

I'm checking that out today. Thank you for the recommendation! I popped off the dust cap and aside from being filled with dirt somehow, it spins freely. But i sprayed some wd-40 inside into the raceway, and the noise subsided briefly. So definitely the culprit, just a matter of taking it off now.

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A clutch pulley has an inside spline (or hex) in the bore of the pulley and a 10mm or 11mm nut inside the spline. A simple pulley would just have a larger nut. Be sure to look for reversed threads if you attempt disassembly.

So the Gates set listed above fits according to their website. Only negative is the set is over $100, which isn't the issue--more that it's over $100 when you only need 2 bits out of the set. I'm giving this one a whirl OEM TOOLS 27261 Alternator Decoupler Pulley Tool Kit, 5 Piece | Pully Sockets and Shaft Bits fit Most OAD and OWC Pulleys | Alternator Repair Tool, Designed for Universal Use Amazon.com: OEM TOOLS 27261 Alternator Decoupler Pulley Tool Kit, 5 Piece | Pully Sockets and Shaft Bits fit Most OAD and OWC Pulleys | Alternator Repair Tool, Designed for Universal Use: Automotive.

Arrives Thursday. I'll let y'all know the verdict on the tools. Still want to pull the pulley off and see if it's in fact the pulley or instead the bearing inside.

I've had bad luck with bearings lately. My 2 yr old ShopVac had a bearing in the motor explode. Of course ShopVac wants you to replace the entire motor assembly for $60. Can anything just be made well anymore?? Outside of my 4runner, of course.

Considerably off topic, but if you do ever have a bearing go out in a ShopVac, they are an exact match for any skateboard bearing set. A local skate shop actually gave me one for free when i went in to get one. Works like a champ.

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It's good to see picture of the clutch pulley. Given all the rust(?) or dried grease(?) I suspect your clutch pulley lost lubrication and failed. I'm wondering if you can use the decoupler pulley tools to remove the clutch pulley without removing the alternator. If you're able to do this, you can check for a noisy bearing inside the alternator by spinning the shaft. If no noise, replace the clutch pulley with the alternator still in the vehicle and you should be good to go assuming the alternator was charging OK before the noisy symptom. See YouTube video GATES TRAINING: Alternator Decoupler Pulley Inspection and Replacement - YouTube and watch this time segment 2:53 to 3:05. Have you seen this video? If not, I recommend watching it. I've always rebuilt starters and alternators, so I'm very interested in what you're able to do with yours.

Was hoping the pulley would get in before this happened...

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Wow, that belt is shredded into little pieces. If only it could have lasted a couple more days. Nuts! Is the alternator rotor frozen? Have you checked that all the pulleys other than the alternator rotate freely without excessive noise or wobble? If yes, this demonstrates that a properly working clutch pulley reduces stress on the belt by allowing the alternator rotor to spin freely during engine deacceleration. If the alternator rotor is not frozen, and this happened to the belt because the clutch pulley failed, then I'm wondering if the belt tensioner was damaged by excessive belt vibrations over a long period of time. Check for excessive belt bouncing after the alternator is repaired.