So I’ve used Valvoline Dexron-3...
Can anyone tell me if the Dexron III is appropriate (good and bad experiences) and if it’s not recommended, what should I use?
I've never used transmission fluid in forks. I mean why? There are so many dedicated fork oils available?
I'm a Bel-Ray fan too OWD.
Other than that, I guess the real question is, how do they feel with that oil when riding? The weight of the oil will change the way your forks respond, which also depends on riding style, bike, and rider weight, etc. That's why it's advisable to use a dedicated fork oil that you know the weight of as a starting point.
As for 'pegaxs'... if you cant find the info in a manual, then bleed the forks and measure what comes out of each tube. As accurate as you can. Then use that information as a guide, not a guarantee, but consider it a starting point concerning measurement.
Remember the response of the forks can not only be tweaked by the weight of the oil, but also the amount of oil you use.
Keep the level of each fork tube exactly the same, as best you can.
Use one of those horse-like syringes to add and subtract.
Ride, test, and tweak...