I ran Amsoil synthetic ATF in it for the winter & then switched to Amsoil GL-4 80W90 synthetic gear oil when the weather warmed up in the spring. I still have a bit of notchiness going into 2nd unless I shift very slow & deliberate, but it doesn't grind like a bad syncro. Porsche enthusiasts who use the Swepco 201 80W90 petroleum GL-5 gear oil in the Getrag G50 5-spd trans consider the Swepco a wonder fluid for smoothing out the gearbox so I'm considering trying it. Normally one should only use a GL-4 spec fluid & not use a GL-5 spec in a manual trans that has bronze syncros since there are corrosion issues, but Swepco claims to have anti-corrosive additives to resolve that issue.
My gut feel is the synthetics I've been running are too slippery for the syncros to do their job properly so I'd like to see what a good quality petroleum product does for it.
gale
92 735i 5-spd, turbo project finally underway!
Don, I'm running Redline MT-90 in the Getrag 6-speed and also have that notchiness that you describe...not a bad synchro (grinding)...just stiff. I was going to try some Mobil 1 Synth ATF for the next winter season based on what some of the E34 M5 crowd was saying...we'll see hoe that goes. I too think that too much lubricity is making the #2 a bit hard...although the Redline is good for the rest of the lube, no doubt. I hadn't heard about Swepco but I'll ask my indy (and his fave Lipstick Red 944) what he thinks of it. I'm looking for the smooth shifting grail as well...
Cheers,
Duey
1995 540i/6 Sport Pkg w/E.A.T. chip and Nikasil injection Duey's Gallery