Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - Strange thud noise from transmission when downshifting

- Issues | Warranty | Recalls / TSB (https://www.ft86club.com/forums/forumdisplay.php?f=72)

- - Strange thud noise from transmission when downshifting (https://www.ft86club.com/forums/showthread.php?t=127070)

Strange thud noise from transmission when downshifting

I’ve only had this happen to me maybe three times since installing my short shifter/changing my transmission fluid back in February, and I’m not sure what’s causing it. Basically, when rev matching down from 4th to 3rd or from 3rd to 2nd, as I shift down gear to gear there is a quite audible thud or thunk sound that sounds like it’s coming from the transmission tunnel. Has anyone else had the same issue?

Some background:
My local shop when swapping out my transmission fluid back in February swapped my factory fill for Motul Competition 75W-140 GL5. I’m planning for my next oil change within the next couple of weeks and will ask them to swap the competition for Gear 300 GL4 in the proper viscosity of 75w-90, as I cannot confirm whether the different fluid is harmful or not... he recommended it to me as he runs it in all their Subaru’s, and me not doing my research beforehand I accepted. However, I don’t think the fluid would be the root cause of this.

As for the short shifter, the FT86SF short shifter has its own host of issues, most notably rattle and a reverse lockout which can’t hold the shift boot properly. Unluckily for me, I cant return it, so I have to wait for a fix from FT86SF. Could the shifter cause the weird thud?

Thanks!

Quote:

Originally Posted by JBezugs (Post 3075619)

I’ve only had this happen to me maybe three times since installing my short shifter/changing my transmission fluid back in February, and I’m not sure what’s causing it. Basically, when rev matching down from 4th to 3rd or from 3rd to 2nd, as I shift down gear to gear there is a quite audible thud or thunk sound that sounds like it’s coming from the transmission tunnel. Has anyone else had the same issue?

Some background:
My local shop when swapping out my transmission fluid back in February swapped my factory fill for Motul Competition 75W-140 GL5. I’m planning for my next oil change within the next couple of weeks and will ask them to swap the competition for Gear 300 GL4 in the proper viscosity of 75w-90, as I cannot confirm whether the different fluid is harmful or not... he recommended it to me as he runs it in all their Subaru’s, and me not doing my research beforehand I accepted. However, I don’t think the fluid would be the root cause of this.

As for the short shifter, the FT86SF short shifter has its own host of issues, most notably rattle and a reverse lockout which can’t hold the shift boot properly. Unluckily for me, I cant return it, so I have to wait for a fix from FT86SF. Could the shifter cause the weird thud?

Thanks!

I'd suggest that you wait till you change the oil back to the recommended type of oil and ask them to check the short shifter linkage at the same time.

:iono:

humfrz

Quote:

Originally Posted by JBezugs (Post 3075619)

did you run the short shifter while on the factory fluids ?
i do wonder if the fluids are a bit low when it got changed over.
or the short shifter link is offset.

Quote:

Originally Posted by Grey86 (Post 3075631)

did you run the short shifter while on the factory fluids ?
i do wonder if the fluids are a bit low when it got changed over.
or the short shifter link is offset.

I ran the new fill with the factory shifter for a month or so, had no such issues (at least I don't think so anyways...); could be the short shifter causing the issues, but I will be swapping the fluid anyways as I'm not comfortable with the "incorrect" fluid in the car currently.