[Funkycheeze]

Did some digging.

Most current Toyota PN for 3.73 7.5" ring and pinion is 41201-80107. Cost from Mr. T is around $850 USD *ouch*

Looks like it was used in the front axle of KZN165 diesel Hilux trucks, which are fairly common in Australia. Replacement R&P is available through aftermarket retailers for a more reasonable rate:

https://www.allfourx4.com.au/Crown-Wheel-Pinion-Kit-Toyota-Hilux-KZN165-Front-41201-80107
https://www.terraintamer.com/en/4wd-products/transmisson-driveline-cat/crown-wheels-pinions

Not sure why it comes with a new flange... But could be worth a shot for someone? Perhaps directly contacting them you could order just the gears and save some $$...

 

[Funkycheeze]

087-012396k is a good PN too - might be the same kit, but is from a company called 'drivetech'

 

[ToyodaSup]

Going brand new is a surer bet for quiet operation. Used, the same F code 7.5" R&P is plentiful in the Previa vans. It is a solid axle though so the internals will require swap out from the pumpkin to the clam shell. The u joint mount on the pinion flange is larger so it might offer and improvement it strength if it can match the driveshaft.

 

[Funkycheeze]

Yeah the larger pinion flange is a popular upgrade - it is also on the front of older pickups and 4runners. 3.73 gearsets can be found on supercharged previas, older 2WD pickups, 4cyl 2wd 2RZ powered tacomas with automatic transmissions, some Cressidas, '82 mk2s, among others.

 

[mutantcolors]

Lexus IS250.

When I was new to the forum I figured that out on my own. Got told I was thinking too hard. Then other people started doing it. Makes me smile.