loud engine noise, ideas?

Sounds bad, how many miles? Any warning lights on the dash?

 

Take a long screwdriver and use it like a stethoscope along the top of the engine or wherever the you can get to and try to narrow the sound down.

 

Maybe it's coming from your water pump. Does it get louder if you point your camera to the water pump area? It's the area where the belt is connected to

 

Toyota puts a donut between the block and exhaust manifold, my '06 needed a new one arounf 40,000
I went aftermarket to get a better than oem part, the muffler went at 60,000 again aftermarket

 

Ouch, if it's a whining sound, it's bad news.

I had that on a 250k mile prius, needed a new transaxle.

 

I would think if it was coming from the transaxle there would be metal shavings in the transmission fluid, I would drain the transmission.

 

That sounds like a shot water pump. When was the water pump last replaced??

 

Does not sound like exhaust leak but a few similar threads people posting noise videos, the exhaust manifold had hole in it from rusting through. @Prius_Cub had that.

 

Reason there’s no codes is it’s strictly mechanical like a bad bearing.

Trans might have fluid leak and is low or out of fluid primarily caused by bad inner cv joint seal wear. You may see it weeping where the inner cv joint axles enter.

Sounds like a bad chain in the trans. Or a bad timing chain in the engine.

How do you take care of maintence of the car. Who changed
the oil and what kind of oil?

But if you think it’s the trans pull the trans fluid. If it has metal on the magnet and fluid filled with particles it’s done.

Reports of trans differential gear failures and thrust bearing failures
But both somewhat rare and reflect poor fluid maintenance but I have never heard audio of the symptom.

Go to lusciousgarage.com and search there repair blogs. They discuss various trans bearing failure.

Mechanical trans failure is pretty rare on this site it’s a world class trans.

 

Btw lots of used trans on eBay. Usually easier to pull the engine trans as a unit.
Price on trans is $300-500 with fob and labor is $1000 but this is at an indie mechanic.
If dealer does it the car will be totaled at $140 an hour labor forget it.

 

I think the diagnoses of needing a new transaxle is probably correct. But the reason for it "a bearing problem", is probably not correct

 

The prius doesn't have clutches or torque converters.

 

So they pulled the trans fluid? Or just said yup its the trans?

Try the long screwdriver trick.Go to harbor Freight and get a long heavy duty screwsdriver and hold the metal end to the area of interest and put your ear on the handle end. Its the dixie cup on a string deal. Stethoscope is the right way but not everybody has one of those. You will clearly hear the area of noise.

Try to isolate it It sure has a hollow bad chain sound to it. If it was the engine timing chain I suspect it would throw crankl/cam timing error most likely a missfire code.
If its the trans chain there may not be a code as the timing relationship to final drive and mg is not monitored for phase. The mgs are monitored for phase for proper firing of the 3 phase but mechanically downstream post chain there is nothing.

Its rare. I want to see trans fluid before I commit to new trans.Spend $50 and pull the fluid. Magnet should be bushy with debris.
If pristine the trans is not your problem.