testing viscus coupling

Have a 94 ZJ 5.2 with 225K miles on it, just rebuilt the front differential and the transmission and am looking at what to do with the transfer case. I don't want VC problems to mess up my new drive train so I was thinking about changing it but wondering if there is a way to bench test it. There was just a little binding feeling when backing out of parking spots in the morning, but allways did well in the parking lot test but I have no way to tell if this has ever been changed and with 225K on it it has to be getting to the end of it's life. The inside of the case looks good from what I can see with the coupling out. The chain is pretty tight and the rear bearing seems pretty good also. There wasen't much fluid in the TC which leads me to think that it's probably original and the seals need changed. My first though was just to change the coupling and seals and run it but would like to get a few more opinions. I had thought about changing the chain and bearings too but they seem to be in pretty good shape. I do like the 249 case, this is a highway driver and it does work well in snow. I had thought about swapping the TC case but don't think the rear end would survive too much spirited driving anyway in 2 WD. Highway MPG has allways been around 19-22 at 55-60 which I think is pretty good for AWD and I don't think a swap would gain much MPG although smokey burn- outs would be a lot of fun.