Rear End Trouble

[440 challenger]

Hi everyone. Just joined. I have always been a Chevy man, but I bought my first Mopar, 1971 Challenger. It was about 3/4 completed when I bought it. To make a long story short, it has a 8.75 489 case . I bought 3.55 Motive gears, all new bearings etc and had them installed. I removed the case, and had someone install the gears, etc for me. I installed case after rebuild and it made a whining noise when you let off the gas. the mechanic said to drive it and it should quit. I had my doubts. Drove it app 600 miles and removed it and took it back. He checked it and said it was ok . I then took it to another mechanic and bought new pinion bearings etc. He reassembled set all tolerances to Motive specs. I reinstalled. No noise when you let off gas but now it whines all the time except when you let off gas. He says it is because the gears have established a wear pattern. Is this right? Need help. Thanks for any help 

[Moparal]

Sounds like they both smoked ya to me.  One was to tight, the other to loose.  Does the yoke have any play (wiggle) in it when not hooked to the drive shaft?  I wonder what the mesh pattern looks like. If it was in the center, or on one side or the other of the gear.  Pinion depth is a big factor, and also side ring gear contact.  Either one could make it sing

[72rtchallenger]

Sounds like they both smoked ya to me.  One was to tight, the other to loose.  Does the yoke have any play (wiggle) in it when not hooked to the drive shaft?  I wonder what the mesh pattern looks like. If it was in the center, or on one side or the other of the gear.  Pinion depth is a big factor, and also side ring gear contact.  Either one could make it sing

doesnt sound right,I set up my own it takes alittle time and right tools but not that hard,I reused my old gears and replaced all bearings and crush sleeve,,the only whine I have ever heard was when in reverse and from tranny which seems normal to me,,but the rear is quiet and gears are orignal,and no more miles that you have put on it .should be no whine,,it was my first time at doing this so I dont think you should have this problem with someone that does it for a living

[Chryco Psycho]

any gear set that whines is set wrong , no break in period will change that & after the gear pattern has been established it may be impossible to eliminate the whine ever but I agree it is set wrong again now

[440 challenger]

Do you think it would be worth my time to remove and try to find someone to reassemble or get new gears and start over? Also is there any thing I can ck once it is removed to try and locate problem? Thanks

[Chryco Psycho]

for the $$ already spent I would try again to set them up , make sure you have a proper pattern on both sides of the gears

[440 challenger]

With it  making a noise all the time. except when you are coasting, what would be the  most likely problem

[Chryco Psycho]

the load side of the gears is out of alignment

[440 challenger]

How is this corrected? Thanks for your help !

[Chryco Psycho]

probabaly more or less pinion depth , you would have to look at the pattern tured so tell for