Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I would get sheet of Nitrile rubber(Buna-N) or Viton and cut the sealing ring from it. As a precaution submerge small piece of it in ATF overnight. It will probably swell a little but it should not become too soft or harden. If I remember correctly you don't want to use natural rubber for hydraulic oil or ATF.
Beware of modern hoses and gaskets. Recently I bought 30 feet of what it thought was high-quality ethanol resistant fuel hose from Semperit (our equivalent of Goodyear). It started softening after 10 minutes in gas with 5% ethanol and blackened the gas in the can by dissolving. Imagine this **** slowly dissolving on the hot headers as you go for test drive after fuel system rebuild! I was pissed at Semperit but then I checked their fuel hose catalog and discovered that I bought almost certainly a knock-off. Lettering was in different font and was missing some of the factory markings.
I didn't know that silly cap was so rare and expensive. Many times over the years I left mine off after tinkering and found it under the hood somewhere. Lucky to still have it and will be more careful.