Miata nb 6 speed issue

Today i installed a 6 speed gearbox on my 90 miata. Its a blast! Really wake up the weak 1.8 in it.

It shift smooth beside the sloppy shifter and all gears engaged smoothly. 

But, when in 4th and 5th gear, if push the shifter slightly to the right (like resting my hand on its side, the transmission make a grind noise. Only in 4th and 5th, and only to the right, nit the left. 

I searched and didnt not find a yota on this issue.. 

Could it be the loose shifter bushings? Bend shift rod or forks? 

physician said:

Today i installed a 6 speed gearbox on my 90 miata. Its a blast! Really wake up the weak 1.8 in it.

It shift smooth beside the sloppy shifter and all gears engaged smoothly. 

But, when in 4th and 5th gear, if push the shifter slightly to the right (like resting my hand on its side, the transmission make a grind noise. Only in 4th and 5th, and only to the right, nit the left. 

I searched and didnt not find a yota on this issue.. 

Could it be the loose shifter bushings? Bend shift rod or forks? 

 

I don't know if applies for the 6 speeds, but my 5 speed needed a shifter rebuild kit that replaced various parts and it made it a lot better.

In reply to RyanGreener (Forum Supporter) :

it will sure improve the shift feal.. but im wonder if it will solve the side-load grind...
Just asking before i drop 150$ in oil and bushings..

finally solved the issue, there was a missing bolt on the tail shaft, the one that hold the shift rod bearing.. no grind anymore. but i found out why it was opened at the firt time: to remove the speed sensor spiral drive.. so down it will come again... ;)

Thanks for the followup! That might help someone someday.