[QUOTE=Steinkrunk;4624282]The reason that you need gl4 is because of the brass synchros our transmissions have. The additives in gl5 will eat these away and make them take a shit. If you have a tranny that runs good with gl5, just give it a couple months of some repeated hard use and you'll wish you had used gl4 from the beginning.
OP, you sound like you have a pilot bushing problem. It's the little bushing that goes between the end of your crank and the trans input shaft. Once it starts to go it makes a whine, and eventually it'll make a whine in all gears. Also you could check your tranny mount, if it's worn it could be stressing the pilot bushing/input shaft and causing the whine.[/QUOTE
i don`t intend to argue, but todays gl5 will not harm brass synchros or anything in the transmission for that matter. the factory rec. gl4 because back then there was no gl5. gl5 is a superior lubricant to gl4. gl5 has additives that gl4 does not have. you can use gl5 on any transmission that uses gl4, but you cannot use gl4 on a transmission that requires gl5. i wanted to make sure that i`m not sabotaging myself by using gl5, so i did some research and now i know i`m not. so there, gl5 will not damage our transmissions. you want to use something better, use full synthetic 75-90. it will shift smoother even when cold. AGAIN, i don`t want to argue, just researched to make sure i`m not wrong.
