"transaxle" gear lube.

[TurboElk]

I got my '05 Aveo w/manual trans. a couple months ago, the previous owner had a list of services done at 3,000 mi. ago... one being "transaxle lube" (I'm thinking he means transmission gear lube) he has written down GL5-75/90... I see it calls for GL4 (?)... the guy at the parts store said the GL5 "is caustic to the synchros" ??? I've never heard of this, but I've realy only delt with Muncie manual transmissions.... So how can gear oil be caustic?
Thanks for any help.

[avguy]

There is a fair amount of information on the web saying that the sulfur content in GL5 will eat away at the brass synchros. Like with many of these things, those of us who are not closely connected with the auto industry can't know for certain how valid this is. I will say I decided to use Redline GL4 to top off the gear oil in my '05 when I replace the CV axles last year. But I'm guessing I didn't need to do this, and that GL5 would have been perfectly ok, especially for just a small amount. Your Aveo will probably be just fine with GL5, but if it keeps you awake nights, you can change it out for GL4. However, be advised that refilling is a fairly tedious job, unless you have access to a lift.

[TurboElk]

Thanks avguy... I didn't think about looking that up on the Internet.