Nsg370 box oil change kj 2006 (6 speed)

Hello, I have a NSG370 manual transmission (6 speed) in my KJ 2006. I want to make a change of fluid. What is the correct grade? 5w-30 75w-80 75w-90.
I have knowledge that there Mopar fluid, but do not want to use, and I'm looking for a better quality.

- In service technician told me that Jeep uses 75w-90.
- In Wikimedia claims to use 5W-30.

What is the best for this transmission to improve the smoothness of gear changes?

Thanks for your help and recommendations.

Service Technician is full of it. That trans requires 5W-30.

Ok. is 5w-30.. ¿API GL4 o GL5 ? other chapters?

It's 5w-30 gear oil (not motor oil)... I still don't get why you don't want to use Mopar fluid... It's the easier/better thing you can get...

Cheers!

I have heard that it's synthetic oil Mopar

it requires synchromesch fluid which happens to be of 5w-30 viscosity. penzoil makes it! so do alot of others! the spec is ms-9224

Thanks

I need to investigate whether synthetic Mopar is to be 100% secure.

The transmission uses Nsg370 1.5 lt?