Does anyone use amsoil 20w50 in 6speed gearbox? I use shockproof on my other ride, wanna try something different this time.

 

Try any 75w140 gear oil. 20w50 shears too fast in a trans.

 

I'm using Amsoil in my tranny, but I think it's the Heavier Blend.

 

+1 on what the others have said. 20w50 is motor oil. Use gear oil in the tranny...

 

Spectro 6 speed. Specially formulated for the HD 6 speed. Works great.

 

Thanks guys! I thought the 20w50 might be a little too thin, seen ppl recommend it here and there, just wanna make sure. I don't know if I should go 75w90 or 75w140, the hottest day we have here is 97f, what do you think?

 

I use a straight 50W fully synthetic for my transmission. I work at an OEM semi truck dealer (forman) and use the transmission gear oil we sell. I believe it IS the best on the market. Made for gearboxs that exceed 300'f and has crazy shear strength. In the trucks it has 300k mile change intervals. It is stupid expensive but at 1qt. Per change I drain/ fill both boxes when I change my oil with Amsoil 20/50.

 

I have read where oil weight and shear strength have less in common than once thought hence new cars using 0w20 for fuel mileage. I say use 20w50, enjoy the benefits of better shifting and change your oil like a normal person and don't abuse it.

 

I use amsoil 20w 50 in tranny. Never a problem for me.

 

I also use Amsoil 20w 50 syn and have had no issues. That's what's in the manual so I figure they know what they're talking about. Different strokes for different folks I guess.