For Street, I like 80/90 non-synthetic oil. Lucas is my personal favorite. For Strip, 85/140 non-synthetic. My go-to is Swepco 210.
First, don’t dry shift your new unit, you’ll damage it. All new transaxles come dry, so the first thing to do it to put oil in it.
After you reinstall the trans and motor, just adjust the clutch. Start your car and go for a little drive. It’ll oil and loosen up right away. The more you drive and shift, the smoother it gets. All BENCO boxes are built with tight tolerances. This helps ensure it’s longevity and trouble-free operation.
After about 300 miles, it’s good practice to change the oil just in case there was any minor debris left during assembly.
Unfortunately no. There are only a few parts in a pre-67 trans are reusable on a quality rebuild. We will accept 6volt cores as a return, but only for partial credit. Please call for current prices.
If the bell housing has been ground, it’s a dead give-away it originally was 6volt. If not, look at the outside diameter where the starter bushing is pressed into the case. If the outer diameter is 5/8″ hole, it’s 6volt. if it’s 3/8″, it’s a 12volt.
Also, all IRS are 12volt.
Yes, for the street, change it after 100 miles on a new transaxle [some metal shavings on the magnet is totally normal]. After that, every 15,000 miles should do. You could probably go double that without any issues but changing it more often keeps if fresh, well lubricated and gives you the opportunity to check levels and inspect everything.
As for off-road, change it after the first trip, after that, I personally change it after ever 100 gallons of fuel or once a season. That’ll keep it happy.
Racing, after every race. Better safe than sorry.