aketay

Running the Mobil1 75-90 synthetic gear oil in the trans and rearend. Cheap and quiet, not as much metallic fuzz on the magnet at change interval. Took off rearend cover for insprction @ 250k miles and it still looks like new, no shine on gears yet.

Danderson, watch out with the Valeo clutch kit. Mine only lasted 75k miles before the pilot bearing and throwout bearing destroyed the entire clutch, clutch fork and input cone on the trans. Before that, my factory DMF lasted 171k miles until flywheel springs broke, never slipped.

Danderson

Yeah,thanks. I was going to have a Con OFE installed,but the tranny guy had installed a dozen of these Valeo's mostly to long distance hauler's with great success. He's installed lots of OFE-FE's with the owner's coming back complaining of jumpy performance. The guy's been a tranny guy for 37 yrs.

It's only got 5K on it,so I should be good to go for awhile. I've got the itch to use more of the power,so it'll probably be coming out sooner than later.
My DMF was perfect@ 37K. The installer has seen many input shafts destroyed by the stock dmf's.

SolarExpress

My G56 has gotten really noisy in the past year. It was probably 45K miles since last oil change using the recommended ATF. The change seemed to quieten it up a little but it gets real gravely (perfect description Danderson!) once it starts warming up. I am religous about pushing the clutch in when killing the truck but my wife is not. I thought my clutch might be dieing a slow rattlely death (152K miles). You think a little heavier oil might help it? The clutch still performs flawlessly and no slipping is felt, even at WOT going through the gears.

StealthDiesel

A search on "G56 gear oil" will bring hours of reading! And I thought engine oil discussions could go on forever..


I never did get a response from anyone if the Lazersmith 80W-140 Gorilla Juice gear oil would be suitable in a NV5600.

Many guys are running the Gorilla Juice in there G56 trans with good results. I'm not sure how it would do in a cold Canadian winter start though.

In theory, if 80W-140 Gorilla juice is fine in a G56 which Chryslers specs ATF, then it would be fine in a NV5600 which specs 70W-80 gear fluid.
I'm currently running 75W-90 Redline MT90 in my NV5600. Next fluid change I may consider mixing that 50/50 with Red Line 75W-140NS.
I wouldn't mind trying Gorilla Juice but it would be too expensive with shipping to Canada.


Just to correct my earlier post, Delvac Synthetic 50W trans fluid is approximately 90W on the gear oil index.
IMO this gear oil would not be a good choice for a light truck manual trans with a large temperature operating range.

motox40

how much oil does the g56 hold? thinking of changing mine. everyone says to fill 1 qt over, is this true?

marathon

Yes! I quiets lots of noises.

If you can lift the passenger side of the truck, you can add the additional qt when you change the fluid. Most owners go through the top, giving you a chance to inspect the shift tower boot which is often torn or deteriorated. Costs about $120 for replacement.

Hintonc393

I got up the nerve to try the mobil delvac 50 and it seems to be great. I had six quarts of castrol ATF+4 in it with two bottles of lucas oil additive. I was expecting the oil to be a little thicker when it came out but it looked and felt like plain old ATF. The Delvac 50 seems to work great, the trans loves it, shifts are smoother and the extra thickness of the oil removes some of the rattles at idle. It is a little better with the delay going into gear but not much. Going to look into a Fluid damper soon to try to remove some more of the noise.