Not saying they should fall on and off. A light press fit, did mine and my brothers that way years ago. Both cars run T/brakes and no issues. Last time my 60 was apart, I changed gears, beautiful pattern but gears starting to get sharp. I will attribute that to 3500+lbs. and a transbrake on a street gear that was in the car for 10 yrs. The spool bearing surface that had been polished looked just like it did 10 yrs. ago when I did it. As did the pinion shaft. You don't just sand away til the bearing drops on. The way I see it, the gear change was routine maintenance in heavy car with a brake. JMO