Do any of you believe in additive for Oil, Tranny Fluid, Gear oil and such?

I have an OLD motor that is in it's original build but is leaking a little oil out of the rear seal. And I'm sure the Tranny, T-case and axles would like some fresh oil as well. But are all those expensive additives really worth it?

20/50 oil and 2 bottles of no smoke worked well n my criser engine when it leaked ot the side cover plate. :D jiMMy

I got good results from a climbing oil additive in shutting up the gear whine in my TC

So do you have any brand names to suggest?

The climbing oil additave is called Power Punch There are three different ones. There is one for ATF, gear oil, motor oil. There only 3.95 ea!