If you have a G-56 and are wondering about the Delvac swap....do it.

[Northfork]

For any of you new guys or others wondering about this, here is my take.
A week or so ago my pal and I put the truck on the hoist and drained that...that "stuff" out of the trans. The truck only has 40k on it. We installed the Trans-Cool coolers on in place of the PTO covers
and then pumped it full of the Mobil Delvac 50 Synthetic Transmission Fluid. With the coolers it took 7ish quarts to get it to the bottom of the full line, but we got an extra 12 a quart in there.
The Delvac is extremely slippery...to these old hands anyway.

It didn't take but about 3 miles for me to notice the trans was quieter in every gear. I am happy.

 

[seafish]

I have been driving my 2005 with 2 gallons of Delvac 50 in my G56 with TransCoolers for several months now.I also noticed less noise and easier shifting with one exception--

It is MUCH more difficult to take the transmission out of 1st or 2nd and put it into neutral at low speeds going downhill on cold mornings.

Have you experienced that??

 

[Northfork]

No sir I haven't. It would stand to reason that until it is warmed up a bit it would be a bit tighter to shift until it warms up. It has been in the mid 30's here in the am. This stuff is much thicker, the ATF-4+ does not impress me a bit. I will look for an alternative when I do the transfer case as well. My best friend of 40 years owns a transmission shop in our little town and I will follow his advice.
We were going to do it when we did the trans but it was closing time and he was headed for vacation so I waved it off. I can get on one of his hoists with just a day or two notice.

 

[EDankievitch]

I had tried all of the fluids reccomended on here in the 2 G56 units I owned. I found Pensoil Sycnromesh seemed to give the best cold and warm service and wear protection.I even tried the fluid spec'ed out by Mercadies (Sp?) as it's their transmission and found that below 40 degrees I could not shift it in the morning. Way too thick. I just ran accross RoyalPurple brand Syncromesh fluid if I still owned a G56 I'd be running it. I've become a huge fan of the Royal Purple products. Just my 2 cents...... I know the factory fill is +4 ATF and yes that floid is thin.... However how many Auto Slush boxes are out there running ATF with much higher Tourque loads running through them lasting many miles.... It's really not that bad a fluid as long as it's kept cool..... Just sayin...