There’s a lot of confusion out there when looking for info on a 4 to 5 speed O2O trans swap. With photo bucket crapping the bed there's also a lot of missing picture links out there. Hopefully this will help explain somethings and tell you exactly what is needed.
5 speed trans with proper gear ratios
5 Speed Selector lever
5 Speed Selector Ball
5 Speed Bar linkage (Black Endcaps)
1 - Start with the trans..
It should NOT have a wishbone mount popping out from the rear section. Later O2O’s had this with the Mk2 platform. You need to remove it and replace it with PN 171711586A .
To install this part on a trans that had the mk2 wishbone mount, remove the mount from the trans by taking out the 3 bolts. Then remove the short bolt on the right side of the trans near the top. Use that same bolt to attach the new selector.
There’s a similar one from the 4 speed but it looks a mm or 2 shorter on the longer lever side as seen in the 3rd pic below.
2 – The Large ball end selector
3 – Longer 5 Spd Selector Lever
4 – 5 Spd Bar linkage
Some thing’s worth noting…
Yes. You can use the rest of the linkage from your 4 spd; like from the shift knob all the way up to the ball end under the firewall.
The distance the lock our needs to be from the lever box under the car is 20mm iirc. Tape a 20mm allen key to the box and use it to get yourself near where it should be.
After completing the swap, if 1st is a bit sticky to get to cheat. The bent bar with the black end caps. Put it in a vise and squish it a bit to straighten it out.
Rebuild the 5 spd trans while it’s out. Don’t just trust it good like I did and have a mess to deal with. Us ARP bolts so self machining won’t ever be an issue.
I also have some easy ways to align the shift lever. Set the trans in first gear (second might be easier but I use 1st). Now just push the bottom of the lever against the lockout and slide the other end of the rod into the clip at the front of the vehicle by the firewall. Make sure the bottom of the shift lever stays pressed against the lock out. If you're having issues afterwards it's as simple as loosening the shaft clip and slightly spinning the rod further away from the lockout. I like to mark the shift rod end in relation to the clip so it's easy to tell how far I've spun it. Hope this helps.