Originally Posted by
themage21
Mine is a '00 GU - part of the bunch that had the crappy 5th gear from factory. It had towed camper trailers in the previous owners usage, not sure what it did in owners before then. It lasted 260k - not bad for a second rate part. But if you have to take out the gbox one way or another, I'd always vote reco, unless you know that the replacement box is from outside of the affected year range.
Additives aren't going to help, because it's not a heat/wear thing, the splines actually tear and round over from mechanical overload/fatigue. I've got my old layshaft and gear and you can see where the shoddy gear never engaged with the end of the spline. Outside of that, the shaft and gears all look like they're brand new, because of regular oil changes.