Castrol or Valvaline synthetic NV4500

[Blackbumper]

Which do most prefer to to run in their NV4500 Castrol Synthethic 75-90w or the Valvaline Synthetic 75-90W. I can find the Valvaline all over but the Castrol is hard to find.

 

[BigPapa]

The Castrol Syntorq is the "proper" lube. It is a GL-4 gear oil. That's the important part. The GL-5 gear oil will damage the synchronizers. I run the Amsoil MTG found here:

AMSOIL - Synthetic Manual Transmission and Transaxle Gear Lube 75W-90 (MTG)

Scott

 

[tony597fitter]

I was running the Amsoil MTG, and I switched to Royal Purples Max Gear for GL-4 trannys. I have to say that It feels as thought it shifts smoother with the Poyal Purple.
I even had my wife drive the truck and she agreed with me.

Poyal Purple is cheaper and easier to find.

 

[01smoker]

There was a big article in TDR about this same subject last fall. They tested all of the different kinds and brands with drag tests, wear tests and i forgot what else and the Castrol Syntorq beat all of them. Amsoil and Royal Purple were close behind though.

 

[cummins724]

Castrol Syntorq if you are running stock style synchronizers. I switched to brass synchronizers & I'm using Amsoil in mine.

 

[BigPapa]

I switched to brass synchronizers...

This sounds interesting... Hows this working for you? Where'd you get your stuff? I'm looking at rebuilding mine next month.

Thanks,

Scott

 

[cummins724]

This sounds interesting... Hows this working for you? Where'd you get your stuff? I'm looking at rebuilding mine next month.

Thanks,

Scott

I had my tranny rebuilt by Advanced Diesel Technology. He gets his parts from Blumenthal. The brass synchros make shifting tighter until they break in, then they shift like stock. I like them alot.