My 88 v6 with a 5 spd trans gets kinda sticky at times, especially from 2nd to 3rd. It doesn't happen all the time. Mostly when hot. Clutch adjustment and free play feels right. I don't think it's the syncro rings because it doesn't grind, just sticky at times. I've replaced the fluid with ATF as specified by my Haynes manual. Is there a good additive I can add?

 

assuming you have an aluminum housing there is no additive i know of that will do what your wanting it to do. the case being at hand is ... does your ATF have enough weight to insure proper lubrication. this question has been pondered every since they started using ATF in manual trannys. the fact of the matter is tranny fluid is 10w most gear oil is 80 w. ATF has a tendency to deteriate plastic parts faster than regular gear oil. i don't care what any service manual tells me. i use gear oil. have never had a problem using gear oil in any tranny specified for ATF. in cold weather it takes a while for the gear oil to loosen up but, you are assured of better lubrication. if your problem persist i would think about trying gear oil on make next change. just my opinion. Sick