Need help w/ transmission and rear diff.

[1st-time-Z-owner]

The tech at the nissan dealer told me to change the transmission oil to full synthetic but when I asked him the weight he did not know, so Im kinda doughtfull on his suggestion about the change in transmission fluid to stop the noise it makes. My question to you guys is whats the weight for the transmission fluid and the rear differential. I could use you guys help with this, cause im going to have it change tomorrow. They have told me to go with Royal Purple....What you guys think??? Any sugestion will greatly be appriciated.Thanks.

[evildky]

I'm assuming you have a manual trans? and honestly I don't know the spec for the manual trans I assume it's standard gear oil like the diff, gear oil only comes in a couple of weights, at least most stores only carry one or 2 weights, 80w90 I believe is what you need, napa stocks royal purple and it is good stuff, honestly I find no significant difference in them vs, redline or mobil 1, I just get whatever full synthetic is stocked where I happen to be shopping