Light grind when downshifting from 6th to 5th

Your truck transmission has a shifter that goes directly into the box. You will fell a lot more than what you would feel in most other vehicles that are cable or external rods connecting the shifter to the trans.

Have you tried double clutching? It sounds like a lot of work but really isn't. You just need a quick partial jab at the clutch pedal to pull it out if gear then a full press of the clutch to put it in the next gear. This worked so well with my 91 toyota I started shifting my 03 WRX this was too.

 

I would check the clutch pedal Freeplay as it could gone out of spec due to clutch wear.

https://www.tacomaworld.com/threads...h-engagement-adjustment.640297/#post-22110291

Edit: I would actually flush and bleed your clutch fluid prior to making any adjustments as any air in the line will throw the adjustment off, ask me how I know. It wouldn't hurt to check the master and slave cylinders for leaks while your working near them.

 

Didnt see anything out of spec for the clutch. May try to flush the fluid after. But I suspect that its not the clutch since no other gear has this feeling shifting except this one gear.
My thinking is maybe a few things could be happening. Synchro is wearing out prematurely or fluid is contaminated. Clutch is slightly touching due to wear and tear/bearing/fluid out of spec. Maybe a bushing/mount is failing.

What I think is most likely happened is that either a bearing inside the trans is failing or clutch is worn. I dont think a synchro would go out this early. Ive also replaced the fluid 4 times to this point at 59k miles. The shift feels like a phone vibrating heavily just as its slipping into gear.

OEM 0k > RL MT90 25k > RL MT90 50k > Amsoil 55k. There was more dust in it then I thought there would be and none of it was magnetic. so wasnt exactly sure what it was in there.


Regardless, I have 500 miles under warranty and ive dropped off the truck at a different dealer last week and will have them replicate the issue.

Image is from the RL MT90 fluid change to amsoil at 55k. 5k old fluid shouldnt really look like this in my opinion.

 

It's too late now, but that would've been a good opportunity to snag a sample for Blackstone to analyze.

 

I went with the RL MT 90 as well after my OEM and it felt a bit more notchy almost immediately (no bits seen when drained). I double clutch almost all the time now and this seems to smooth out all my shifts. Watching thread and wondering if anyone else had notchy-ness (is that a word ) after trans fluid change.

 

Just got back an update from the dealer. said that nothing felt wrong, they took it on a test drive to see if there were any issues and there were none from their end.

regarding the notchiness. that’s something i’ve had with the transmission from day one. i expect that’s normal.

 

I had the "notchi-ness" too along with difficulty getting in to first at a stop and an odd sensation of the syncros working with a faint grind when shifting to second.

A change to the Motorcraft fluid and all that went away immediately.

I did some study about this before purchasing, the product is very popular in Miata circles. Below please find a quote from one such forum.


I am well aware that this is just one unsubstantiated data point, not a full on engineering study. However I felt it was representative of the general consensus I gathered during my reading.

"If you're talking about the Motorcraft, it was designed for use in the Getrag designed for the Focus, not the 'Stang. The Focus(especially the SVT) had a HORRIBLY notchy and hard to shift transmission from the factory and Ford called upon Fuchs to design a transmission fluid that would alleviate these issues. This is where the 'miracle fluid' legacy started as it quite literally made these cars feel like a new transmission was dropped in them. Then people started using it in all sorts of different transmissions with overwhelmingly positive results. I know the Speed3 guys love this stuff almost as much as we do(but we're better because RWD!)."

 

i’ve just ordered 3qts of the ford oil and i’ll try it out. i’ll flush it out in another 5k miles and see what happens.

dealership said nothing wrong the truck and it’s what i suspect they would say. at least it’s more documented. i’ll take legal action if it gets worse.