Don't wanna get hosed by a transmission shop

Driveshaft ujoints and center bearing are good?

 

It's been my experience that Toyota manual trannys don't like synthetic oil. I'm a fan of Redline oils but not in Toyota manual trannys, and especially not if the syncros are showing signs of wear. I agree with everything Bassackwards has stated here. OP came asking for help and I agree that the choice is either try a heavier gear oil for a few bucks and buy some time or replace the tranny. It doesn't make sense the problem will magically go away after a few thousand miles.

 

Do whatever you want. It was a recommendation that solved my issue. Take it or leave it, im not saying my word is gospel

 

Just a note for the wise. The most common enemy and cause for syncro wear is resting your hand on the shift knob while driving.

 

Try shifting without using the clutch to find the "sweet spot" for that particular shift. Hardly ever used the clutch in my Ranger. Sybchros were gone and it never would grind.
Or Double clutch.
Or Skip 5th gear.

 

Yes I was pretty bummed out when I had this same grinding problem and I searched the internet for answers. I was very skeptical after reading the glowing testimonials about MT90. Maybe mine wasn’t as bad as the grinding only happened shifting above 4000 rpms. Being the lazy guy I am took the path of least resistance. I will also admit driving an X encourages me to drive faster than normal, still does and I cannot explain why the situation resolved itself. Looking back I purchased the X used as third owner with 94k miles. I did all the fluid changes not knowing when or if they had ever been done, I went with factory recommendation on fluid types. It was later I decided to try the MT90. As I said I cannot explain why it worked for me but it was cheaper than buying a new box. I also replaced clutch, throw out bearing, pressure plate and pivot arm before the first fluid change. I’ve had the vibration problems which turned out to be universal joints worn out, both cats have gone bad and that’s not a cheap fix, but it’s still a badass truck at 142k miles and running strong. I run mobil1 5w30 and the factory YZZD3 filters.