The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - What's the right lubricant for a stock 3-speed transmission?

66K10383 · 07-27-2011, 02:59 PM

I cant find straight 90w these days. im 99% sure thats what the tranny called for. in my SM420 original tranny I used NAPA 85-90w, same as the front and rear differential. My tranny made the same noise you describe, I changed the oil/metalic paint

and it still makes the same noise. Honestly im not worried, these trannys are beasts

07-27-2011, 02:59 PM	#3
66K10383 Registered User Join Date: Jul 2011 Location: Spokane Posts: 42	Re: What's the right lubricant for a stock 3-speed transmission? I cant find straight 90w these days. im 99% sure thats what the tranny called for. in my SM420 original tranny I used NAPA 85-90w, same as the front and rear differential. My tranny made the same noise you describe, I changed the oil/metalic paint and it still makes the same noise. Honestly im not worried, these trannys are beasts