lightshine 0 Report post Posted March 26, 2013 What oil should I use in a daily driver e30 diff (non lsd) Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2122 Report post Posted March 27, 2013 good ol manual gearbox oil. your one of the few RWD drivers that actually bother to do the diff lol Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 27, 2013 You don't use gearbox oil. The correct oil is hypoid full synthetic 75w90 which is not suitable for gearboxes, only diffs. Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2122 Report post Posted March 28, 2013 You don't use gearbox oil. The correct oil is hypoid full synthetic 75w90 which is not suitable for gearboxes, only diffs. just checked my stash. this is the manual gearbox fluid i use and was reffering to. surely, like engine oil, next to no difference between 75 and 80?? or is my manual gearbox fluid wrong? but have used this stuff in all the diffs and manual gearboxes of my E30s never had any issues. Quote Share this post Link to post Share on other sites
Allanw 1051 Report post Posted March 28, 2013 Depending on the actual specs of the particular oils; 75W90 can be quite a bit thinner than the 80W90 when cold, giving better gear changes while cold. Once warm they the same 75W is about the same viscosity as a 10weight (or some of the thinner 20weight) engine oil, and 80 is more like a thicker 20 weight or a 30weight. I wouldn't rush out and change it, but I'd look for the 75W90 next time The thing with the diff, is that it MUST be hypoid, where you can get gearbox oil that isn't hypoid, though it's not that common on the shelves. Quote Share this post Link to post Share on other sites
