Shortshifter TRD - Issues

[pack]

Hi everyone...

I have a question that it is bugging me for some time.... When i swaped the 20V in i still had the OEM shifter on my AE86. My gearbox was opened to check for issues and nothing was found, so the gearbox is still mint!

Car shifted OK no issues at all..... Then i found a decent and cheap TRD shortshifter complete with all the parts.... I assembled it... And......
Well, since day 1 on the new shifter i've been strugling with shifting from 4th to 3rd.... It is sometimes really hard to shift down at the tracks and even with the so called heel and toe becomes really hard....

Most of the times, shifting from 4th to 3rd is smooth like butter sometimes it is a pain....

What could be the cause for my problems with the shifter?

Thanks