mark kibort

I cant believe how easy this fix was, once I studied what was really going on in there. I also cant believe no one here thought about it.

those shifter forks have to allow for the gear selector in the transmission to move the slider bars fore and aft to select a gear. If one side vs the other is out of alignment, the transmission will stay in gear as the next gear is selected, but the next gear cant engage, and you cant go back to select the prior gear. so, at that point you are hosed and need to take the top of the transmission cover off. fortunately have the removable hatch to do this while the trans is in the car.

the shift forks are clamped on to the shifte slider shafts. (I don't know what they are really called) via a 13mm bolt. loosen this and you can move the forks to engage earlier or later in the shift movement. I moved it 5mm and made it mirror the other gears appearance. now , its impossible to move it to 4th from 3rd, and have it still be in 3rd when the 4th gear slots align. I love it..... a permanent fix ..................... however, it doesn't solve the 2nd gear pop out problem, but that's minor compared to this issue. Lost a race due to this one time and a lot of track time and qual positions. never again!!

mark kibort

Here are some shots of the changes and reasons why

the first two are 3rd and4th gear selected. you can see that the gap is too small in 3rd gear showing that it will start going into 4th without it being pulled out of 3rd gear.

the second two pics are marked with a magic marker to show how much I moved the forks

the third two pics are the holbert transmission which was used for comparison. 3rd and 4th selected.

mark kibort

I took it for a test drive today, knowing the 3rd gear lock up was fixed and looks like all around better alignment for going into the 1st reverse area.

BUT, Guess what I found????????????????????????

its drivng great. solid going into 4th. no chance of that lock out happening,,,,,,,,,,,,,,BUT.............
I notice its ROCK SOLID in 2nd. no poping out of gear with no load. NONE, NADA!!! PERFECT!!!!!

why didn't you guys think of this? GB was saying its caused by the synchros being worn at the edges, but the sychros for shifting have always been fine. now I know...... it was due to a missalignemt of the shift fork..... It's moved to the same position that the holbert position has it at , and its FIXED!!!!!!!!! shifts better, doesn't lock out in 3rd and no more pop out in 2nd. NO MORE one hand driving in turn 2!!!! cant wait to race it!!

SeanR

Why haven't you picked up a nice Cayman S to race?

mark kibort

why a Cayman S??? actually, it would do well in WCGTS, but very expensive when set up as a capable race car.

Lizard928

I think you must be missing some of the pins.....

There are some pins in the nose of the transmission that prevent you from engaging two gears at once....

Landseer

Mark did you happen to find a service manual for the 85-up trans?

mark kibort

engaging the gears at the same time is not the same as engaging the slider bars at before the 3rd gear is released. you are then still in 3rd gear, the 4th gear bar is engaged and then you are stuck and the gear shifter doesn't move. its normal.... I could do this to any transmission with the cover off.

if you see how you go from 3rd to 4th, you can see that if 3rd doesn't get released, before the 4th gear slider (those silver movable bars that attach to the forks that move and engage the gears) is engaged, you can see you get locked up.
from the pics , top two, you see that moving 3rd gear out, the 4th gear opening opens too quickly, so that 3rd is not fully released. this is because that shift fork. (the bronze part) needs to be moved so that as you push the gear lever to 4th , it pulls it out of 3rd gear completely, before you can engage the 4th gear slider and then push into 4th for engagement.

I moved that bronze fork about 3 to 4mm in the direction that forced 3rd gear release before 4th could be engaged.

not only does that fix the lockout problem from ever happening again, but it solved the 2nd gear pop out problem

mark kibort

I have the big manual, with transmission section

mark kibort

I was out looking at It again, trying to make sure of what I did. It looks like the reason that the lock out problem fixed the pop out of gear problem, because there is a spring loaded keeper pin at the front of the transmission. if the slider bar doesn't move far enough, its between the 2nd and neutral spots. (there are 3 spots under the keeper spring for 2nd, neutral and 3rd). by moving the shift fork by 5mm, it now properly aligned the indentation spots on the slider shaft, so that it cant pop out of 2nd under no load conditions.