Manual Transmission (operating fluid?)

[WarEagleDiesel]

My Truck:



2009 – 2500 – 6. 7 – Manual Transmission – Completely Stock



I purchased my truck, brand new. Transmission was extremely tight until about 10,000 miles. I’m approaching 50,000 miles, and the transmission seems a little more loose than I’m comfortable with, having driven a 1995 Dodge Ram 1500 with a 316 engine as my first vehicle. This may prove to be a poor comparison to present day technology, and the fact that my previous truck was a gas burner and I now drive a diesel, but, I changed the transmission gear dope about every 50,000 miles (adding Lucas oil products after 150,000 miles). I sold the truck with 225,000+ miles on it, and the only transmission component I ever replaced was the clutch, 2 times.



I maintained a 50,000 mile transmission interval to check and change the transmission gear dope. So I referenced the owner’s manual of my 2009, and it lists ATF+4 as the operating fluid in present manual transmissions. Is this correct? Just want to be sure. If so, I know with automatic transmissions it is not recommended to change your transmission fluid, only add to it over the life of the vehicle. However, what is the recommended practice, since I have a manual transmission, that is using ATF+4 as the operating fluid? Change the fluid, or just add to it to maintain proper operating levels?



If, in fact, ATF+4 is the correct operating fluid, what is the viscosity comparison to 80W gear dope? If the viscosity of ATF+4 is less than 80W gear dope, could this contribute to the “loose” feeling that I am experiencing?



Thanks for all your input.

 

[TLane]

Both my owner's manual and service manual say to check the manual transmission fluid level at every engine oil change and change the manual transmission fluid every 60k miles. It says ATF+4 is the proper fluid.
I think the ATF is much thinner than 80W gear lube. But I wouldn't change to any thing other than what the factory recommends. There are also warranty implications of using the wrong fluid.
I've never heard of NOT changing the automatic fluid. I've done it on other vehicles I've owned; in at least one case it cured a shift "shudder" problem. In the other cases it was a matter of preventative maintenance.

 

[CKelley1]

the g56 uses atf4+ the 80w gear lube will ruin it. the g56 needs to be filled one quart over full. the type of cut on the gears makes the g56 shift smoother than the old. i do not think you have any wear at all. we have a gauge on our atf4+ lube gun and it is a piece of cake to get the extra quart in. most either drive the truck in a ditch or fill it through the top

 

[AH64ID]

ATF+4 is the popper fluid.

Not changing ATF in an auto trans is a myth, and usually does far more harm than good.

 

[Joseph Donnelly]

Standard Transmission & Gear has rebuilt a lot of G56 six-speed transmissions. They almost always find that the bearings are brown from heat and ATF degradation. They recommend using the Pennzoil Synchromesh that is correct for the NV5600, or similar fluids, especially if towing or heavily loaded.

 

[OBayer]

Standard Transmission & Gear has rebuilt a lot of G56 six-speed transmissions. They almost always find that the bearings are brown from heat and ATF degradation. They recommend using the Pennzoil Synchromesh that is correct for the NV5600, or similar fluids, especially if towing or heavily loaded.

I was just reading about this myself.



Has anyone switched to the Syncromesh fluid and was there any change to the ease of shifting ?

 

[Bob V]

I changed to Royal Purple synchromax and seems to be fine. I wanted a little more viscosity than the ATF

 

[macdaddy]

Manual transmission's requiring ATF usually have some needle bearings. I am not sure if thats the case with the G56. If there is this type of bearing ATF is required.



ATF has a different sheer/film strength for that type of bearing.



Mac

 

[NIsaacs]

I changed to Royal Purple synchromax and seems to be fine. I wanted a little more viscosity than the ATF

I agree and while I don't use synthetic, I do use 15/40 engine oil, the same as the engine. I use it in all three of my trucks with all different manual trannys. I always figured the ATF weight oils were more for fuel savings then transmission longevity. I don't have a G56, but if I did, the same oil would be in it.



Nick

 

[HBarlow]

I'm not invested in the issue but having met and talked with the folks at Standard Transmission, toured their facilities, watched them work, and had them overhaul a NV-5600 for me, I'd trust and follow their recommendation to shift the G-56 to Pennzoil Synchromesh Lube.