chadzeilenga
Active member
Hi All,
I'm finishing up the fluid change in my 89. I have GL-5 80W-90 on hand have have read up on the differences between GL-4 and GL-5 and that GL-5 may not be the best for yellow metals within a transfer case, but I'm confused by the statement in the FSM stating "API Classification GL-4 or higher". What has me confused is the "or higher" statement. I searched within the forums and couldn't really find any recent discussions on the topic. While not wanting to start another oil war, does anyone have some input?
I'm finishing up the fluid change in my 89. I have GL-5 80W-90 on hand have have read up on the differences between GL-4 and GL-5 and that GL-5 may not be the best for yellow metals within a transfer case, but I'm confused by the statement in the FSM stating "API Classification GL-4 or higher". What has me confused is the "or higher" statement. I searched within the forums and couldn't really find any recent discussions on the topic. While not wanting to start another oil war, does anyone have some input?