Hintonc393

I just installed a valair dual disc clutch in my truck. Now my truck is harder to get in gear when stopped, this is NORMAL. It is caused by the mass of the extra clutch disc spinning on the input shaft. I am 100% sure that my clutch is not dragging with the pedal down. What I want to do to help this is run a very heavy fluid, on cummins forum there is a guy that dug up a application for the g56 in a medium duty truck where 75w90 is used. Anyone doing this? I was also thinking about running two quarts of Lucas oil stabilizer with either five or six quarts of ATF is anyone doing this?

Danderson

I unsuccessfully ran Gorilla Juice which I believe is about that weight. Waaay too stiff for cold/cool weather shifting. A fleet owner has used SAE 50 Delvac blended 50/50 w/Amsoil 5-30 synthetic MTF with great luck.

Standard transmission in Texas is recommending Pennsoil Synchromesh(what I use) or Amsoil 5-30 synthetic MTF.

More gear noise is the real deal without the dmf.

I test drove one of the early SBC 3250 DD's and didn't have any problem getting into any gear. Just too much racket.

C Schomer

I remember a fews yrs back, some guys were mixing Redline syncromesh lube and Redline 75w90 but I don't know the ratio. I think Redline can tell you. Craig

Hintonc393

Wow still to thick in San Diego?

Danderson

Yeah,in my case I thought the shifter was going to break off,literally. I've only read one other post where the owner experienced such extreme stiffness.

I think I'll follow Carl48's suggestion about the 50/50 blend of Delvac SAE synthetic and Amsoil 5-30 synthetic next. He's done a pretty thorough job of documenting his results using tranny heat sensors and longterm miles on his fleet.

Hintonc393

Was the stiffness only when it was cold?

StealthDiesel

Interesting discussion.

While I have a NV5600 6 speed manual, I also have a Southbend 3250 dual disc clutch. It's the early style that rattles with the clutch pedal in.

I am running heavier 75W90 gear oil in it to help longevity & quiet it down when it's hot. I've read about some guys running a partial mixture of 75W-140 in it also.

75W-90 gear oil rating is about 15W-40 in engine oil rating.
Gorilla Juice gear oil is rated at 80W-140. I wonder what that is in engine oil rating?

This is the 1st I've heard of someone running Delvac SAE 50 engine oil in a G56. 50W engine oil has got to be in the 75W-140 range I would think.


Here is the link to Gorilla Juice & G56 info: http://lazarsmith.com/Transmission.html

I wonder if anyone has run Gorilla Juice in their NV5600? Perhaps worth a call to Lazersmith??
It's pricey at $18/quart plus shipping. Red Line 75W-90NS or 75W-140NS gear oil is about $11/quart locally.

Grit Dog

I noticed no difference in shifting ability when I installed my SB OFE (not a dual disk though).
I changed out the factory ATF at about 20k mi for Amsoil ATF with an extra qt of Lucas trans oil stabilizer (1 qt over full as reccomeded by a long haul hot shot driver on here a few years ago). Trans has performed flawlessly.
Just changed the fluid at 100k mi recently and it looked surprisingly clean and no difference in shift quality from old to new oil.
I'd say stick with ATF in it.

Danderson

Beyond stiff when cold. Much stiffer than Pennsoil or ATF when warm. It did an excellent job of gear noise suppression.

Danderson

Mercedes doesn't recommend ATF. Dodge apparently recommends it to cut inventory. With the DMF swapped out for a smf,the G-56 gets pretty gravelly in neutral,clutch out when warm. Standard Transmission began seeing G-56's come in with premature internal wear with ATF. That's why they're recommending something heavier and one xtra qt. They won't warranty a rebuild w/ATF.

I would think Delvac SAE 50 synthetic would be 50 wt. The op feels that is too thick,so he recommends diluting it 50/50 w/5-30 Amsoil MTF. I believe he states they're getting hundreds of thousands of miles out of these G-56's with this formula.

Carl48 is the author I believe on this site.

StealthDiesel

Danderson, what are you now running in your G56?


I've never even heard of Mobile Delvac 50W before....

Amsoil 5W-30 MTF is about 70W-80.
From the Mobile website, Mobile Delvac 50W is equivalent to 90W gear oil.
So a 50/50 mix of the 2 will end up about 75W-85.

Not very different from the Redline 75W-90 I'm running in my NV5600.
I always thought that the Dodge spec'ed Penzoil Synchromesh for the NV5600 was like water.

I'm not scared of running heavier gear oil as I run Red Line 75W-140 in my rear differential. But I do tow a 10k lbs 5th wheel around all summer.

Danderson

I'm running Pennsoil Synchromesh. Shifts nice cold or hot,but I do get the gravelly neutral,pedal out noise when the tranny's warm/hot. I'm going on Standard's recommendation. I think I'll give them a call tomorrow and see what they say currently.
I know of one member running Amsoil MTF. He formally was running GJ.

John Bellmyer

Just had a SBC dual disc installed and am not happy with the noise that is now coming from the G56. Was told that the stock DMF absorbed alot of the trans noise that is now heard with the SBC. I drained the ATF and put in 8qts of Pennsoil manual trans oil. Shifts fine and some of the noise is gone but still to loud for me.

Farmboy_92

I just had a South bend dual disc installed a few weeks ago in my 06. I'm running the Pennzoil syncromesh and the only noise i've noticed is around 1100rpms or lower in 1-4 and 6 but its not very loud. In 5th gear below 1500rpms it will growl pretty loud.

Danderson

Yeah,mine's silent on the freeway,but driving through parking lots,I've got some gear noise. I'm sure the engineers contracting with LUK for a dmf after driving the G-56 with a smf. The addition of amy Fluidamper did nothing towards decreasing the G-56 noise,but it did noticeably smooth my idle.
I've got a Valeo sdf in here which is completely stocklike aside from the tranny noise at idle,pedal out.
The only reason I converted it was that I had a rear main leak. The installer said that the dmf was perfect @ 39K.