What's the best (efficient) manual gear oil for a Corolla (89)? I'm leaning towards Pennzoil Synchromesh after reading this thread:
http://ecomodder.com/forum/showthrea...wners-128.html, especially the last post (on p2) by AndyH.
But synchromesh isn't rated for the Corolla? If I found the right manual, I should be using 75W90 GL4 or GL5. I don't know how the synchromesh is different, but it doesn't have a weight or GL4 rating. But it is for a manual transmission, so won't it protect my gears adequately? The only evidence I've been able to find of Corolla owners using synchromesh indicates they mix it with more conventional 75W90 gear oil.
Background: I think the generic 75W90 I (and others) put in the gearbox is too viscous. Evidence?
- I've had a 'high rolling resistance' when cold problem with this car for at least a year. It's a bit subtle, most drivers wouldn't notice, but the contours of my driveway make it really obvious to me when I glide out and I'm also very suspicious I can 'feel' it affecting my glides.
- Reading around, oil in the differential seems to be the most critical in viscosity for MPG, some reporting as much ~10% improvement in MPG as a function of oil selection (30% in drivetrain losses for Metro's EV, which is a smaller number than above, although temperature may be a factor). In either case that seems generally consistent with my feel for cold weather drag on my Corolla.
- I know the rolling resistance is in the tranny, jacked up and removed front brake calipers and tested all 4 wheels by hand. (Previously I thought I heard drum brake dragging and did a new spring kit back there, might have helped (and I don't hear dragging now) but it didn't cure.)
- The clutch got rebuilt by a local shop in Feb 2012, most likely they changed the tranny oil. My memory isn't sharp enough to say whether that was exactly when I noticed the resistance, but it's a prime candidate.
- Also about the same time, I think I started noticing the shifting was a bit sticky. It's not grinding, and it's not a big deal, but there's more resistance to getting in and out of some gears when the drivetrain is cold, especially in cold weather.
I've changed the tranny oil twice since Feb 2012, once because I didn't know the shop had most likely changed it and I thought it was due and I had noticed the resistance, and again because I replaced a drive shaft. In both cases it was before I knew that all gear oils are not equal and I grabbed the cheapest 75W90.