redmed wrote:The factory fill was semi-synthetic while MT-90 is synthetic. Don't know if that was a big factor in the difference. I'm hoping so, I'd like to see a improvement with the reverse gear. It is downright embarrassing sometimes and every time it happens I think about chipped gears and metal shavings in the oil.
What I'm referring to is the difference between two synthetics Royal Purple and MT-90 seemed to indicate the the thinner MT-90 was better. True?
It may be a few weeks before I travel that way to get the Redline oil and possibly some rear shocks. Then later in the fall before I change the oil in the transmission and engine, rotate tires and modify or replace the rear shock bumpers.
I still have the Reverse gear engagement issue with MT-90. I just think it's a characteristic of the transmission and it being a little sloppy. I don't think the new fluid will fully cure it and will merely alleviate it if anything. I just find that you have to really throw it back in there and make sure to have a positive engagement or it will grind a bit and not go anywhere.
The RP Max Gear and RL MT-90 were in my Mazda3 that called for 75W-90. I don't recall one feeling significantly better than the other. I used RP Max Gear first mainly because I felt an odd sensation in the clutch pedal when shifting. It was a light vibration. It was shortly after I bought the car with 56K miles. I changed the fluid somewhere around 60K with Max Gear. I chose Max Gear out of convenience; it was sold in my local AutoZone. It immediately remedied the vibration issue permanently and made gear engagement a lot better. I used that fluid until about 100K or so. I then changed to RL MT-90. I do not recall MT-90 offering any memorable improvement over Max Gear. At 109K, I sold the Mazda3 as I already got the Kizashi by then.
The reason I like Red Line's MT-90 and MTL is because these fluids were specifically designed for manual transmissions. That's what the "MT" in the names stand for. RP's Max Gear was great and made an improvement in shift feel and performance, but is more marketed as a gear oil and is merely suitable for some manual transmissions among differentials.
Given the preferred weight of 75W-80 for the Kizashi's MT, I think Red Line's offerings are better than RP's. Max Gear's thinnest weight is 75W-90 and their Synchromax Manual Trans Fluid seems to be a one-weight-for-all product from what I can tell.