SR20DET (S13) gearbox shifting issues in AE86

[heshan]

Guys,

I've done a SR20DET swap into my car and since the swap putting to 1st and reverse on a cold start has been next to impossible with regular gear shifting force.

I need to really push it in hard with god-like force.

So went to my new mechanic and got the entire GB dismantled and guaranteed its the brass cornes that's causing the shifting problems. I didn't think it should cause it but however he was adamant that it was the cause so replace the brass cornes for the 1st, 2nd and 3rd gears. But the problem still persists.

I insisted that he should check the master, slave, clutch and the flywheels but he insists that they are in good working order.

I'm using the S13 prop-shaft coupled to my ae86 diff with a slight slopy-angle where the gb sits about 15-20 degrees above the diff which I don't think is the cause for this but just putting it out there.

I think its the clutch or the master/slave that's causing this but can't explain why its only affecting 1st and reverse. Or the gear oil. I'm using SAE90 again as recommended by my ex-mechanic.

As mentioned before this only happens when the cars on a cold start. Once the car has run around 10 mins the gears shift well so makes me think its a oil mismatch as well. Maybe I should go for 75w90 gear oil to allow the cold start problem to solve but given that those gear oils in my country and expensive I want to ensure that I've explored all other possibilities before moving to a more simpler gear oil change.

What could be the problem? Anyone with this same gearbox able to help me?