Very Wierd Tranny Problem

[Streetsweeper21]

I have a 90 Gsx with a 92 Jdm Galant Vr4 Tranny Switchable Awd<>Fwd. It all started after I swaped out my turbo to put my 16g in. Everytime I go to 3rd gear it lets me go into 3rd than when I let go off the clutch it pops out. If I hold the clutch down it will stay in 3rd but soon as I let go the clutch it pops out. If I try to hold it in 3rd gear and let off the clutch it grinds. Than my 4th started to do the same thing kept poping out of gear everythime I let go off the clutch. 2 days later after driving in 1st, 2nd, and 5th my 3rd gear decided to come back but my 4th gear was still out. That lasted for 2days and now its out again and my 4th is back. So now im startin not to think its the syncros but now sure any advice would be helpful thanks alot

 

[yokotabrat]

I'd check to make sure there isn't anything obstructing the transmission shift arm. Have someone shift gears for you when the car is off and look at the shift arm on the tranny as it goes through each gear and make sure nothing is in the way. Also, make sure the cables are secured to the transmission bracket and that the bracket isn't loose or bent. Also verify that the cables are secured to the shifter base inside the car. Easiest to start with the simple stuff rather than tearing into the tranny. Hope this helps.