I have just rebuilt my Muncie m-21 from a '70 GTO and found a slight rubbing noise while accelerating in 1st gear. I was told that the front idler gear my be walking back and rubbing the 1st speed gear. I removed the trans and removed the side cover. The idler gear and 1st speed gear have plenty of clearance.
But what I did find was with the 1-2 slider pushed back It just touches the front idler gear.
The rear idler gear was replaced because the teeth were a bit chewed up. now if I put the old rear idler gear back in, the front gear and the slider clear by .001"-.002". I would think this is still not enough. There seems to be no end play in the idler gears to shim them back away from the slider.
Dose anyone know what I should be looking at to correct this?
Thanks, JT