5th gear grind at higher speeds

I have 2013 mazdaspeed 3 with about 92k miles and today as I was driving down the highway I was doing maybe between 60-70mph and tried shifting to 5th and it just sounded like it grinding so bad and wouldn’t go in. So I went to 6th and tried downshifting to 5th to switch lanes and it just kept grinding pretty bad. I lowered the speed and then it would go in normal but then when I was speeding in 4th gear to switch to 5th it did it again. I noticed that it was only doing this in higher speeds/higher rpms. My question would be is would changing the tranny fluid help at all? Or would my synchro for that gear going out or my clutch/flywheel going out?

 

Check the following:

Clutch Master/Slave for leakage

Motor mounts and Torque mount for excessive movement

Shift cables requiring adjustment or the bushings worn

Transmission fluid level and quality

Anything near the pivot shaft/linkage that could be hitting it or preventing proper engagement

Last would be check the clutch for proper engagement, have an assistant push the pedal down and see if the slave is fully extending.

You only have this issue in 5th? Can you access all other gears without issue?

 

Well I recently put a new Damond pmm and all the bolts are torqued to spec and I rechecked those again today and also for the rear motor mount as well and they still checked out torqued as they should be. I ordered 3qts of the Ford transmission fluid that everybody talks about and I’ll be putting that in tomorrow hoping it’ll help. I checked the cylinder through the interior and exterior and no leaks whatsoever. All other gears go in perfectly fine normal driving or WOT. That 5th gear grind only happened yesterday in highway driving going around 80mph but today it was going in perfectly fine driving in traffic and hitting 60mph as well. I’ll forsure have someone help me check the clutch engagement as well tomorrow.

 

Did you have the issue after the motor mount replacement? If so the cables could need an adjustment.

 

Yes I did have the issue two days after motor mount replacement. And is there a video on YouTube on how to adjust them?

 

Jbr used to have good instructions on his website