Well guys I finally got the 3.90s installed by a good buddy of mine who does these regularly. They are almost dead silent. I have a small hint of whine from 55-60 on decel but anything lower than that they're completely silent. I also took it up to 65 and no noise at all until that 55-60 decel range. The only way I could hear the whine was with the windows up and radio off. I know a lot of people have some small whine with the orange box motives due to the harder alloy.

Overall I'm pretty happy, i haven't been able to get on it but it does seem to have a better powerband, and 1st gear doesnt seem that much shorter than the 3.42's.

 

Good choice Redbird!!

 

thanks hio! i like the gear choice it doesnt seem to short but i think 4.10s might have been. should i be worried about the slight decel whine? like i said i have to have the windows up and the radio off to hear it and its only at the above speeds, sounds like a little tire hum noise. from what i have seen a lot of guys 3.90s have a slight noise so i'm not too worried just curious. i havent beaten on it yet obviously because they only have 125 miles on them. backlash and pattern looked awesome when we set them up, so i dont wanna mess with it lol.

 

My stock 3.42's made noise when the car was brand new. I don't know if these rears ever get perfectly silent. My 3.90's don't make anymore noise than my 3.42's did. What oil did you put in it? 90/140 will quiet it up a little if you put 85/90 in it.

 

thanks hio. my stock 3.42's had a hint of whine at speed between 60-65 and 80-90. these just have a small decel whine around 50. above 55 and below 45 are quiet or near quiet. i used the standard 85/90 oil. it really doesnt bother me at all. with the radio on and windows down you cant hear a thing at any time. as i said the pattern looked awesome, backlash was .009 and preload was good, so i really dont want to mess with it. i know motive says that the orange boxes may whine a tad because of the compound so should i be ok?