4:11 to 3:73 third member swap questions

[cronic]

A little update!
I got Iron pig to send me a rebuilt 3:7x third member with the correct flange and a set of used rear axles and ne axle seals. It came in mid week so I went home from school at my first opportunity and put it all together Friday. The used axles are top notch with the seal area almost perfect. I headed back today after driving around yesterday and am totally pleased with the new gear ratio. I am now turning 2200 rpm at 70mph which is 400 rpm lower than the 4:11. Gas mileage improved as well, but I haven't figured it exactly yet, but it is better. The problem I have is that I still have a slight noise from the rear end when I let off and on the gas. It is not nearly as bad as before, but it is still there none the less. In my experience these noises don't magically get better, and only get worse. I am stumped as what to do next. Is a slight noise ok? Or should it be completely noise free, the rear end that is. I have Valvoline 75w90 synthetic oil in it right now. ??????

 

[sepr2]

Noise has a lot of meanings. Is it a whining, grinding or something else? Sure its not the tranny and the gear swap didnt change the pitch?

 

[cronic]

Noise has a lot of meanings. Is it a whining, grinding or something else? Sure its not the tranny and the gear swap didnt change the pitch?

Same whine as before, just not nearly as loud and a much shorter duration. Maybe a 1/2 second. Sounds like its from the rear end to me?