The mystery transmission oil

Had some service done the other day, which included changing the manual transmission oil on my 2016 5 speed. For grins I looked up the part number on the invoice, 08885-80306. When I search it

$46 Toyota Genuine Parts 08885-02106 Hypoid API GL-5 75W-90 Gear Lube - 1 Quart

this is one of the first returns. As you can see the can says "GL-5," which we know is not good for manual transmissions with synchronizers. I asked my mechanic about it and he said this is what his supplier has always given him for the OEM manual transmission oil on 3rd gen Tacomas, saying it was safe for transmissions with synchronizers. I'm not buying it. Unless I'm missing something?

 

Appears to be for differentials

 

Thanks. I'm going to change out the oil myself and put in what's for certain the right stuff. I still have to drive the truck for a couple days before I'll be able to change the oil. Will the transmission suffer damage in the short term?

 

That is correct GL-5 trashes yellow metal the Toyota synchronizer pictured below has worn so much it bottoms out and no longer grabs.

 

So can this oil sit in the transmission for a few days without damaging it too much? Would driving it accelerate the damage caused?

 

It will be fine for a few days, change it as soon as you can to a proper MT fluid.

 

Unbelievable OP... your case ONCE AGAIN, reassures my OCD about NOT taking my truck to dealer........

This is why I have been learning how to do my own services.. from rotating tires to replacing injectors (not in my taco).

YouTube first, then service manual, then Tacoma world for constructive advice, then do it.

I may not be able to do mayor servicing on my truck because I am not a mechanic but let’s say... if I do not have to tear down a massive part of engine or tranny I might try to do it myself.

 

There are gear oil formulations that meet the GL-5 performance specs that are meant for synchronized transmissions(Redline 79W90NS for example). That is generally sped'd for transaxles though where you have a differential in with the transmission case.

 

Actually, it was NOT the dealer in this case. But I called a couple dealers in my area and the people I was able to get on the phone were no more knowledgeable about what MT oil they're using in their shops. I went to this particular independent mechanic because he had a good rep and was open with me about all my questions and concerns. Nonetheless, yes I too am now convinced that I have to learn to do as much maintenance as I can myself.

 

Interesting. Maybe this is the case with the oil I was sold. But maybe isn't assurance enough in this case.