I have a question. Reverse is very difficult to get into and 1st has started to act like that too. I have changed the shifter to an MGW, done a brass bushing upgrade, and just changed out the trans fluids (old was cherry red). My old B&M shifter had the same issues near the end before I switched over. I’m gonna do a clutch bleed soon too but I don’t know what else to do. I have an adjustable tick master cylinder in it that the pervious owner installed 2-3 years back and it has an ls6 clutch. It only happens when the car is warm too. Car doesn’t grind in any gear and shifts like butter when the car is off and when the accessories are on too. The car lets me go into R but won’t let me get into gear. Any ideas?

 

1st and reverse are common issues with failing hydraulics/clutch...Most likely hydraulics.. and since you have to pull trans to change slave pull the clutch as well to inspect it.