I have a 56 Victoria with a fordomatic and a 3.22:1 rear end. The rear end now has about 120,000 miles on it. Not long ago, to fix an oil leak I changed the pinion bearing oil seal. I followed shop manual directions and made adjacent punch marks to reestablish the proper preload when putting the universal joint flange back on. I did notice when I removed the universal joint flange nut and washer, that I did not need to use a puller as the shop manual suggested. The flange pulled off easily using only my fingers. There was little if any resistance. I cleaned and lubed the pinion bearing and put on the new seal . I tightened the pinion nut until the punchmarks matched up . By the way. It took considerable touque as the two marks came close to lining up. Now, several months later I hear a humming noise from the rear end when the car is pulling. The noise quits when i let off the accelerator and coast. I have read over the shop manual and have watched several on line videos . I feel I might be able to do the job myself, but I could use some advice. 1. With that many miles should I consider changing the ring  and pinion gears Or should I try to change bearings only. I have a feeling I might get by with only changing pinion bearings.  Also, the fact than the u joint flange nearly fell out makes me wonder if a spacer or crush sleeve is needed. Who sells a good kit for these?