Was wondering what brand of gear oil you guys use in your NV5600 transmission. My friend has a 06 Mega-cab dually with a ho 5.9 and NV5600, he wanted to change over to synetheic gear oil, what brand do you guys recommend? I told him Ams-oil is what i read allot of guys use in their transmission on this site. any input would be great!....also what do you guys think of the transmission cooler fin kit for this transmission? Think he has around 70-80,000 miles on the truck!

 

I run amsoil in my ZF6 and love it. Hell, amsoil is in everything i own now. I've been very impressed with all their products. Best bang for the buck IMO.

 

I believe the oem oil is synthetic.

I switched to Redline Racing MTL - When it was cold, I immediately had a grind when going into third gear. Drove it that way for quite awhile. I dumped it and put in Amsoil and the grind went away immediately.

You need a GL-5 fluid here and it has to be the correct weight (5W10 or 10W30). The Redline was a 80W90 I believe and it was just too thick.

And a tranny cooler sure couldnt hurt. Also a lot of guys add extra fluid through the top shifter plate. The NV-5600 suffers from lack of lubrication.

 

Umm, NV5600 in an 06?? Not from factory...should be a G56.

I've ran SynchroMax, Redline MTL, and Amsoil...each NV5600 reacts differently to each fluid.