Thanks for your patience and information. I tightened the pinion nut very tight. The drive shaft I ordered came with greased ujoints. They fit perfectly in the axle yoke kit. Like I said, everything I installed fit perfectly. No resistance.

Now we're getting somewhere...do NOT drive the car. As Tom is asking above, we need to know your method of torque on that yoke/pinion nut. Unless you match marked the nut's position relative to the pinion shaft I am afraid you are looking at more education. We also need to know what rear it is..489? 742? 741?

I believe it is a 742, but am not 100% sure. I've driven it twice now with no issue, but am I looking at a catastrophic failure in the near future with those noises? I initially used an air wrench and then tightened it with a wrench

Well, a 742 is MUCH more forgiving given your scenario than a 489... But it still takes a LOT of torque..240lbs if I recall correctly. Not easy to do, but the difference between an undertorqued 742 and a 489 is massive in terms of potential howl/whine. Meaning I don't think your torque on the pinion nut is the issue.

If it's truly a 742 or 741

Chances are the air wrench tightened it to about 50 foot pounds, depending on the air wrench of course, and how big it is. The proper torque is about 200 to 250 if I remember correctly, but I'd have to look it up, been a few years.

Gotchya. How do you differentiate between the 489, 742 and 741. Casting numbers?

Yup, the last 3 digits of the numbers on the side of the case.

A 741 or 742 you can torque.A 489 with the crush collar and a new yoke would be tough to get back to the same spec it was.The noise while coasting,but gone when accelerating I'm thinking pinion bearing.It may be frome the yoke torque being off, but the bearings could also have rust or pitting from sitting a length of time dry.
RT

Stop using the word literally, you don't know what it means.

Well, I just looked and its a 489! (2881489) Now I'm worried from what you said.

Everyone else on here is being helpful with information. I'm trying to learn from the car vets on here. You are absolutely no help being the grammar police or making rude comments.

Thanks to RTSrunner, Pacnorthcuda and amxautox. You guys have been incredibly helpful. Thanks for your patience.

Well, being a 489 means you have a "crush sleeve" on the pinion that determines bearing preload on the pinion. You certainly did not replicate this on the yoke replacement. That's not easy to do even if you know what you are doing.

Do not drive it. Your looking at a pig removal, pinion removal, new sleeve or spacer upgrade and reassembly. A fair amount of work.

I suppose as a last ditch, you could try checking for pinion slop (for/aft) and torquing till that's gone, but that's a pretty shade tree approach!

Thank you so much for your input, advice and information. I sincerely appreciate the time and patience.

Or buy a kit and replace the crush sleeve with a solid sleeve and thin spacers, but that is a lot of work also. Measuring, taking it back apart, putting in another spacer and assembling, and measuring, and doing it again, and again until you get the back lash proper. It's one of those things I'd probably have a shop do. I guess they still have those solid spacer kits for that pumpkin/pig.

or simply call Dr. Diff, bite the bullet, and get one of his ready to bolt in nodular pigs and be done with it.DO NOT SHOP AROUND OR CALL ANYONE ELSE. you will be so much happier!

THANKS GUYS!

I remember the first time I did a rear gear assembly. Reset the ring and pinion on my '67 Mustang after blowing the spider gears. I had to take it all apart in the winter in Illinois. Got it back together and talk about HOWLING!!!

Broke the side gears again, and did a better job the second time.

LITERALLY LITERALLY LITERALLY LITERALLY LITERALLY LITERALLY LITERALLY LITERALLY LITERALLY ......Ooooohhhh......I can't stop.....LITERALLY.....Aargh