Transmission oil

[Dutch]

I started with Valvoline Synpower 75w-140 in my transmission and transfer case. Seemed to work ok but I thought there was more gear noise that I would like. Shifting was ok too, nothing great but I chalked that up to my getting used to a non syncro transmission. I did some research and decided to give Mobil Delvac 1 Transmission Fluid 50 a try.

https://mobildelvac.com/en/automatic...ssion-fluid-50

WOW! what a difference. Like night and day difference. Gear noise is almost gone or at least much more what I consider normal. Shifting is much smoother too. I don't' know if others would have the same result but I am sold on this oil.

[Pismopowerwagon]

Interesting, you wouldn't think it would like 50wt or the synthetic but nice to know.

[W_A_Watson_II]

I run the Lucas Synthetic 50 WT Transmission Oil to better protect the yellow metals in these old transmisisons.

[defdes]

I started with Valvoline Synpower 75w-140 in my transmission and transfer case. Seemed to work ok but I thought there was more gear noise that I would like. Shifting was ok too, nothing great but I chalked that up to my getting used to a non syncro transmission. I did some research and decided to give Mobil Delvac 1 Transmission Fluid 50 a try.

https://mobildelvac.com/en/automatic...ssion-fluid-50

WOW! what a difference. Like night and day difference. Gear noise is almost gone or at least much more what I consider normal. Shifting is much smoother too. I don't' know if others would have the same result but I am sold on this oil.

That's spendy but likely worth it, I put Royal Purple in my F250 7.3 manual trans and it made a huge difference.
How much capacity to fill our trans and transfer case?

[Dutch]

I bought 2 gallons and have some left, 6-7 quarts maybe for both trans and transfer case

[53Crusher]

Gear Oil

I've been running Sta-Lube 85W90 in my axles, transfer case and transmission. It is a GL-4 which is not supposed to bother our yellow metals.
https://www.amazon.com/Sta-Lube-SL24.../dp/B000M8RYMC

[Dutch]

The Mobil oil is also gl-4. I was just surprised at the difference. I never expected it to be so noticeable. I know that some oils are better than others for wear and such but to make such a noticeable change took me by surprise

[53Crusher]

Gl-4

Thanks Dutch!

Didn't mean to imply that either of the products mentioned weren't GL-4. Was just pointing out that our trucks are happiest with whatever brand/weight you choose as long as it isn't GL-5 or high in sulfur/phosphorous. Some brands will say GL-4 & GL-5 rated which I would personally avoid. Just my $0.02

[Desoto61]

I know Charles Talbert has posted many times that he runs 50 Wt synthetic in all his transfer cases based on conversations with lubricant engineers. No reason the transmission shouldn't be the same if it takes the same lubricant.

Lubricant tech has come a long way in the last 20 years, let alone the last 70!