07 5 Speed Manual Oil

About a year ago I changed my transmission oil using gl5. The manual states gl4 or gl5. Practically everything I read on the internet or see on YouTube says not to use gl5 in a manual trans. What are your opinions on this? Should I drain and fill with gl4?

 

There's no easy answer to this question. GL5 is typically used in high-stress/high shock load applications as it has more additives than GL4 and is "better" in those situations (high torque, heavy duty, extreme stress). GL4 is typically used in lighter stress applications (passenger manual transmissions). The owner's manual does state SAE

$29 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 GL4 or GL5 for manual transmissions. And unless you have a good reason, I would leave the GL5 in there. Do you notice any difference in shifting? Also, what brand of oil did you use?

 

Probably won't hurt anything although you may get a little better shift quality with a gear oil specifically designed for manual transmissions such as Redline MT90.

 

Thanks, I first used super tech dino as I also changed the differential oil at the same time but was very unhappy as shifting was a lot stiffer. It was intolerable in cold weather as it took at least 5 minutes warm up until it shifted normally. So I changed to super tech synthetic and it made a big difference and shifted normally even cold.

 

My 2015 manual specifies GL3 or 4 (Gear oil type Gear oil API GL-3 (GL-4). I just changed mine again this month and found it near impossible to find a GL4. Both CRC and Redline were out of stock everywhere I looked. CRC told me they were having issues sourcing additives and Redline told me production was down for a while during a move from California to Tennessee.
I ended up ordering Ravenol GL4 from Blauparts in Minnesota. Europeans still love their stick shifts and have the oil.

 

My haynes manual says GL4 or GL5 for manual trans. My toyota manual that came with truck says GL4 only.
Originally had changed to Mobil 1 GL5, but recently switched to Redline GL4 just to be on the safe side. I still have a GL5 in the transfer case and Diffs. Not sure how much it really matters.

Maybe some more info for you here:
https://www.tacomaworld.com/threads/manual-trans.841915/

 

I'm sure you've found lots of info and anecdotes about this, OP, but my experience mirrors the rest of them: Toyota manual trannies don't like GL5 oils. My 1st gen would hate downshifting into 3rd gear when it was warm using Mobil 1. Changing to Redline MT90 made it shift like new again, but even GL4 Valvoline dino oil was better than the expensive synthetics.