MT occasionally locks out 2nd gear

Same issue. Same solution.

 

No, I generally don't rev match when downshifting the truck. But I will try if it happens again and it's safe to be messing with it.

I normally save the rev matching for my spirited runs in the Z28, but I don't even rev match that car most of the time.

 

Im not going to argue that you should from a mechanical standpoint. But just from a fun perspective, getting a rev matched downshift right is quite satisfying.

 

Yeah, this truck is no different than any other manual I've owned, sometimes it doesn't want to go into a gear, typically from neutral to 1st at a stop, but occasionally it happens with other gears. Either releasing the clutch and depressing it again and/or going in and out of other gears is always enough to get it to go into the gear you want. Also works with just holding the clutch in the entire time, i.e. try downshifting to 2nd with clutch in and it won't go, just keep the clutch depressed and go into 3rd or 4th (still clutch in) then go to 2nd and clutch out.

 

To add on as a further explanation, if the teeth are lined up just right that they won't mesh because the input shaft and output shaft is no longer spinning due to being stopped with the clutch disengaged long enough and/or clutch brake being engaged so the input shaft is no longer spinning. And on the rare occasion, the synchro stopping the input shaft just imperfectly perfect where the points that the shifting sleeve uses to engage the gear become perfectly match in a way that keeps the gear from being engaged.

Clutch brakes is more of a thing on heavy duty transmissions, there is no brake inside your tacoma transmission.

Syncros are supposed to alleviate that by speeding up/slowing down the the constant mesh gears so they engage smoothly, but it is not perfect, and never will be as there will always be a points in the gear, despite being initially very fine points, they can meet perfectly in a way that keeps the sleeve from meshing to engage the desired gear.

It is just more of an issue when the input and output shaft speed is null, and using second gear, or any other gear, is a way to find an offset point that the shifting sleeve can use to turn the input shaft ever so slightly so the points of the desired gear where the sleeve engages become offset instead of matched.


Side note, it is good practice go into second, although you can use any gear really, then first on occasion to even out the wear on the syncros instead of using first gear all the time to stop the input shaft from spinning when starting from a stop.

 

The combination of imperfect 1st to 2nd gearing along with the anemic low end power and the vague clutch feel makes this truck interesting at 1st and 2nd gear speeds.

Despite that I'm still happy I opted for the 6MT.

 

Are you still having issues with second gear lockout? I have a 2018 TRD Sport with 70k mi that will lock me out of second gear under certain driving conditions. Rev matching does not help in my situation. This creates a bit of a hazzard as I either have to come to a complete stop in order to shift into a lower gear or I have to shift into third gear and bog the shit out of the truck. Very frustrating especially when going up a hill with traffic behind me...

 

Has your MT gear oil been changed? If yes, do you know if the oil was rated GL4 or GL5. A mistake some people make is using the latest (GL5) rated oil. But our transmissions require GL4 oil. GL4 is safe for copper based synchronizers. GL5 will, very gradually, degrade the brass synchros and eventually hurt out ability to shift smoothly. Not saying this is your issue; but it could be.

 

Yes, I replace every 30,000 miles or so with redline mt90 gl4. Shifts are smooth

 

I replaced my MT fluid with Redline and at 15K miles and noted no improvement. It's still notchy and occasionally crunchy in 2nd and 3rd gears when it's cold. I'm getting close to 30K and will try the Ford fluid next. I've read great things about it from many different enthusiasts driving many different types of vehicle.