1983 245 M46

I posted on here a few months back that I thought the driveshaft was moving a quarter inch due to the rear axle. Thinking it was a rear U-joint lead me to twist only the rear of the driveshaft. Too far from the trans to get the sound. I took another look at it by grabbing the driveshaft on either side of the bearing and twisted. I heard the noise that I thought was coming from the rear axle coming from inside the transmission or OD. Sounded more like the OD.

My OD is working when cold and even then its getting to be just luck if it works. I also have had what seems to be a clutch type slip in 4th gear going up hill and trying to accelerate. I thought at first maybe a tail shaft bushing but from the archives I'm getting the feeling the M46 doesn't have anything like that. Could the OD be the problem. Have I damaged something by driving it for a year like this.

At start I get this metal on metal knock sound coming from the driveshaft. I can tell the driveshaft is moving a bit before it actually moves the rear axle. I marked a spot on the driveshaft where it bolts onto the OD. I measured about a 1/8 inch play and when I turned it fully in one direction I heard that clatter type metal knock I hear when starting out or when there is a release of tension on the driveshaft at a low rpm.

OD? Transmission? Am I on borrowed time and should I be considering a transmission swap rather than a OD rebuild at this time? Thanks.