Hotrod, I ran RT125-13s in the 70's, RT14609s in the 80's and 90's and now run FR and FRO 16210. Nothing ever happens to the FR and FRO's with the synthetic oil we have these days. I bought a very low mile wreck a couple of years ago with a RTLO16139A in it and one my drivers just had to have the 13 speed. They put a worn out shift lever in it that allowed the straight through gear to go half way into gear and chewed the teeth right out of it. I figured I knew all about twin counter shafts until I got into that thing. Never again. I think I got it timed right on about the 5th attempt.
