tl:dr: Timing belt is 13568-79305 and spring is 90506-18066. This is for future reference of the timing belt tensioner spring (the part that tightens the tensioner pulley) since if you go to a Toyota parts dept, they will say it's obsolete. There is an error in the Toyota catalogue that puts the supercession of the original spring part under the timing belt listing, therefore a parts person wouldn't find it without digging around. The original part number is 90506-18045 however this is obsolete. Under this part listing, it does not say a new number or a supercession. So it looks like there's no replacement to the part right? But! If you go into the timing belt parts listing, the original timing belt (13568-88381) actually supercedes to 2 parts; the new belt and the new spring. It looks something like this: 13568-88381 > 13568-88382 > > 13568-79045 > > > 13568-79305 > 90506-18066 In English, this means that the 13568-88381 part superceded into two parts (13568-88382 and 90506-18066) and that the belt superceded two more times into 13568-79305. Hope this helps! Note: Does not apply to 2S/3SFE/4AGE. Only 3SGE and 3SGTE.