Our differential covers use a 9/16 allen wrench to tighten the fill plug. Instead of buying one you could just make your own out of a 3/8 bolt with two nuts because the nuts for a 3/8″ bolt are 9/16 OD. Its a tool you don’t need to often but it is something you can carry easily enough and make from scrap parts around the garage..

“spent lots of time to search, findally i get it, useful finfo me for me!”
Awesome info Ruffstuff! Just installed my D60 cover and was going to buy a allen to fit, but you guys just saved me some $$.
So much excellent information on here. I found it on google.
Hi Ruffstuff,
My name is Pete Rose, and I’m wondering why you don’t make a cover for a 10 bolt Chevy 2wd C1500 Silvy Extracab 5.7. I’m building my truck into a prerunner and adventure vehicle. We do alot of camping and I fabricate a rack to hold our mtn bikes as well as our 13′ Zodiac boat. It fits into the bed sides at the 4 openings at each corner of the top of the badsides. It is adjustable as well. It’s great, and allows us to store all our gear underneth it. I’m also looking for a truss to go on top of my differencial. I love you products and your little sayings that you put in when you dicuss your parts, it’s a great touch, especialy the one on how to position the Heims horizontaly as apposed to verticaly, thats Awesome!! I wish you I could have met you at KOH this year, I am a small part of, Team Fab-10 Offroad/Italy’s, Crew. I think I saw you talking to Fabio the day before the race. Thanks for all your help out at KOH this year!! I’m sure it was Greatly appreciated. See you at the Races,
Pete Rose