Looking for advice and potential suggestions before I actually pull my trans apart.

The application is a cable YS1 trans, Quaife LSD, Special Projects Motorsports final, GearSpeed carbon Syncros, energy bushings, rest OEM Acura.

During my last race the shifter did not want to go into 4th gear from 3rd during upshifts. All other shifts were fine (including the 5th to 4th downshift). Would not happen every time. Would only happen while cornering (3, 5, silo @ BFR). If I held the shifter longer than normal, that seemed to avoid the problem. Once in 4th gear, it never popped out. A double clutch technique would also avoid the problem.

My thoughts in order of likelihood:
1) Shifter bushings or shifter rods
2) Engine/trans mounts
3) 4th gear syncro

Does anyone have any thoughts for me to focus on when I actually get to looking into the problem or tearing into the box (if needed)? Agree with above ideas/disagree/new suggestions/past experiences/... Thanks.

 

Did you check the condition of the clutch?
What kind of clutch is it? sprung or unsprung?
Sometimes the springs on the plate ... if its a spring clutch will cause the grind.
I have pulled a tranny or two to find the spring wasnt in the race ,and either an upper or lower part of the race broke off.

Id give James at Gearspeed a call. He can guide you in the right direction.

 

Not yet. Exedy stage 1, sprung.

Thanks for the ideas. I will give Gearspeed a call and add clutch to my list to investigate.

 

Give me a call when you get a chance 909-476-7252

 

I had this problem on an S1. I put in new mounts all over the place. It got worse over time, started bouncing out of 4th gear over big bumps. Got in the habit of holding the lever in 4th, which is a real PITA at Nelson Ledges where most of the track is 4th gear.

Eventually the problem fixed itself. Rather, it went BANG and I couldn't select 2/4/R. Tip of the shift fork broke off, went rolling around in the transmission wreaking havoc.

 

Shift fork.......... something new to look hard at!