Light grind when downshifting from 6th to 5th

2021 v6 with 6spd MT with 57k miles. Just noticed the truck has a very light grind feel in the shift when downshifting from 6th to 5th. There is no noise at all, just feels like an extra friction feeling when shifting down between the two gears. I am pushing the clutch down all the way and this does happen somewhat regardless of how fast I shift. This also really only happen at 65+ mph. below that its almost non existent. Ive recently changed my trans fluid as well with Redline MT90 to Amsoil and no change so far.
The shift feels like a phone vibrating heavily just as its slipping into gear or kinda like digging through sand. Happens so briefly for about a second then slips into gear.

Ive only noticed this because I moved to a more hilly area and have been downshifting more often. 4th to 5th has been a little crunchy from the get go, but so has pretty much every gear in this truck. But this certain downshift feels different from every other gear change.

Truck is lifted also, but im certain if leveling the truck should not warrant any change in the amount of fluid needed in the trans.
Fluid flush interval as follows
OEM 0k > RL MT90 25k > RL MT90 50k > Amsoil 55k

 

Sounds like every MT i've ever driven.

 

How is the redline, I normally like to stick to oem genuine fluid, you think fluid choice might have anything to do with the grind feeling you are getting?

 

I dont have a large basis to compare things off of since ive only come from OEM into redline. This is my second time flushing it into the truck and i say it does fairly well aside from this issue. But im uncertain if it is because of the fluid or its a trans issue.
From what I hear, the ford stuff is god tier. But im not paying that much money to top off a truck.

 

I changed to the Motorcraft fluid at 30K, the improvement in shift quality was immediately noticeable on the first trip around the block.

RockAuto had the best price:

https://www.rockauto.com/en/parts/motorcraft,XTM5QS,transmission+fluid,13630

 

ill try amsoil first since its whats accessible to me. but ill try ford after if that doesnt fix it.

 

I had a 2013 ford focus and that little car had hands down the smoothest 5 speed gearbox I have ever owned. I will be switching to the ford fluid when I get to the 30k mark on my Tacoma.



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Any ideas what it could be though? dont think changing fluids is the permanent solution.

 

My shifting atarted getting notchy about a week ago. Replaced my fluid and found a bunch of brass/bronze flakes.

Ymmv.

https://www.tacomaworld.com/threads/1st-6spd-fluid-change-how-much-metal-is-too-much.835666/

 

it was the same way for me during my first flush at 20k. pretty sure its just break in gunk. my second flush at 50 there wasnt really anything in it

 

Do you rest your hand on the shifter while driving? That puts excessive wear on the synchronisers, the more hand pressure over time the more wear. Holding the shifter while cruising in 6th would cause wear on the 5-6 gear synchroniser.

Worn synchroniser is all I can come up with, or the opposite you are using 5-6 more than you used to so the synchroniser is just now breaking in.
If it ain't screeching at you it's probably fine. This 6 speed may be robust but IMO it's pretty damn crunchy compared to others I have had.


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that’s kinda what i figured. so cross my fingers but it still makes me worry quite a bit

 

Why are u downshifting to 5th ? 5th and 6th are overdrive gears …If u are looking for more power to pass 4th is where u want to be .

 

Resting your hand on the shifter is not going to do any damage …

 

Here we go!!!




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Plenty of places and situations where 5th will get you up a hill that 6th won’t. Trick is to anticipate that and shift before you start climbing. If you make the choice late, you may as well go for 4th.

 

normally because im going uphill or a slight incline where im losing acceleration in 6th.

and i don't rest my hand on the shifter. im pretty it will do some damage seeing as it directly drops into the trans instead of some kind of more complicated linkage.

 

Update; Just swapped the fluid out for Amsoil, grind is still there. Took it to toyota the other day. Their master tech drove it around for quite some time but said he felt what i was talking about but thinks its normal. there goes an hour service charge. not sure what to do at this point

 

Update again; Taking it to a different dealer. Im pretty sure this a synchro issue after having it taken to a few other shops and buddies for consultation.
Basically the trans really only does it when cold between 6th to 5th at 70 mph. Ill try to get the dealer to replicate with a ride along.
Im thinking its pretty weird that I caught it like this so early? Are these transmissions known to have issues or maybe im just a bad driver. This isnt my first manual vehicle by far.

 

Mine was notchy going into 3rd from 2nd when cold from the start. It smoothed out around 5k miles. I changed my fluid recently, shortly before the 25k mark, because it was becoming notchy again. I had a not-insignificant amount of sizeable brass and some aluminum left in my drain pan, which concerned me. So I documented it in case I have future issues. Changing my fluid has smoothed things bsck out, but I think I will be changing all my driveline fluids well before their service intervals here on out.

Hopefully its not an internal issue. If it turns out to be, please ask the tech to document the teardown and post any findings here.