If the blue stuff is swepco, I can accurately report that the Valvoline 80W90 is definately an improvement in synchro operation. What I can't report is exactly what ailes my trans and therefore WHY it improved the operation.

Still a good data point for people looking to test different methods to improve shifting. If I have learned anything in life (especially related to mechanical and eleectonic issues) it is that there are fewer absolutes than you would think. Because we don't know why a certain oil type or viscosity works for someones application, we can't assume that it will be good for every application. My lesson learned here was try different things and measure the result. This cost me one hour and $25. Well worth it in my case.

Good luck to all.

Larry

JW, I love your twist !

I have never liked swepco, and I know I am in the minority. I just did my gear box, and refilled it with 80W90 stuff from Valvoline. Works great.

I have the same hesitation from first to second - currently have Red Line synthetic, but will try the valvoline dino oil to see if it gets better...

Great. I just spent $60 on synthetic oil and now everyone says to use the cheap crap.

And yes, I opened it to check the color. :(