Once again, the age-old quandary of what lube to put in the G56 6-speed manual trans in the Dodge Ram diesel.
I have been running AMSoil ATF, which is what they recommend for the application. Chrysler recommends their C+4 ATF fluid. In my opinion, Chrysler really screwed the pooch by recommending ATF in the G56, when in medium duty European trucks, Mobil Trans SHC 50 DC was recommended. There was a wide gulf of viscosity between the Mobil fluid, at 15.7 cSt, and the Chrysler C+4, which was 7.5 cSt. I have read a lot of stuff on the Interweb including some lengthy and colorful threads on BITOG that showed up in Google searches. There never is a resolved outcome of any of the discussions.
Mobil Trans SHC DC is no longer available. Nor is Mobil Trans SHC. Some equivalents from other oil companies are available that claim to be replica fluids (of the SHC, not the DC version). But they're expensive.
Now we're heading into hot weather, and it's time for a fluid change. I want something with higher viscosity, but if I want to respect the Chrysler recommendation, I could find a higher viscosity ATF.
I looked on Redline's site, and they have the High Temp ATF, at 9.5 cSt. 27% higher viscosity is a significant step up from C+4. I e-mailed a question on the Contact page, and got a reply from Dave at Redline. He recommended either the MTL or MT85. MTL is 10.4 cSt. MT85 is 12.0 cSt. I have experience with MT85 on my old truck. It gave the best shifting feel of any fluid I ever ran in the NV4500.
And then there is AMSoil MTG, which I ran in the old Dodge because of the higher viscosity. It was 14.0 cSt.
So there are fluids I have mentioned above ranging in viscosity from 9.5 to 14.0 cSt. Which would you pick?
Which fluid for G56?
- Thread starter A_Harman
- Start date
MolaKule
Staff member
I agree with Dave at Redline and considering this a diesel I would probably use the MT85.
A
For what it's worth, I'm running Redline MTL in the ZF6 in my 7.3L
Powerstroke. I think Ford's recommendation is Mercon ATF. I don't think you can go wrong with either MT85 or Amsoil MTG.
Originally Posted by A_Harman
Now that I've slept on it some, I would rather respect Mercedes' original heavy fluid recommendation. So I'm considering Redline MT85 and AMSoil MTG.
Do these transmissions have a failure mode that you're trying to protect against?
I'd think the Amsoil ATF which IIRC is a PAO based syn would easily be a lifetime fill in a manual.
Originally Posted by nascarnation
Do these transmissions have a failure mode that you're trying to protect against?
I'd think the Amsoil ATF which IIRC is a PAO based syn would easily be a lifetime fill in a manual.
Read this:
If you really tow heavy in hot weather I might try the Delvac SAE50/ Amsoil synchro mesh combo again with out the accidental over fill and see if it shifts better because it kept temps pretty low but was impossible to shift towards the end which might have been airation?
If your just looking for extra protection over ATF I've been happy with the Redline MT90 at $75 a gallon at Cartek in Corona, CA
Mobile Delvac 1 SAE 40 looks interesting too but it was $300 plus and could only get 5 gallon pail at the time so MT90 it was.
www.mobil.com
Now it's $210 at summit:
If someone in so cal is interested in splitting a 5 gallon pail of the SAE40 I might be interested so I can try it.
Mobile Delvac/Synchromesh VS. Amsoil MTG 75/90 for G56
Looking for some educated technical feedback not just who runs what or what they like opinions, please. I have a 2009 Dodge Ram 2500 with the manual G56 made by Mercedes Benz. Chrysler calls for ATF+4 in this trans which the viscosity is 35CsT at 40c/7.5CsT at 100c. I've read all of the...
bobistheoilguy.com
If you really tow heavy in hot weather I might try the Delvac SAE50/ Amsoil synchro mesh combo again with out the accidental over fill and see if it shifts better because it kept temps pretty low but was impossible to shift towards the end which might have been airation?
If your just looking for extra protection over ATF I've been happy with the Redline MT90 at $75 a gallon at Cartek in Corona, CA
Mobile Delvac 1 SAE 40 looks interesting too but it was $300 plus and could only get 5 gallon pail at the time so MT90 it was.
Mobil Delvac 1™ Transmission Fluid 40 | Mobil Delvac™ Transmission Fluids
Learn about Mobil Delvac 1™ Transmission Fluid 40 a full synthetic, manual transmission fluid made to meet demanding extended drains and OEM warranty requirements.
www.mobil.com
Now it's $210 at summit:
If someone in so cal is interested in splitting a 5 gallon pail of the SAE40 I might be interested so I can try it.
Last edited:
I’m bumping this thread up. Has anyone tried the delvac 40 synthetic trans oil in their Cummins g56? I’m also considering Torco rtf but it’s really expensive. I’m in Canada.
I won't say that Mopar screwed the pooch.
Lubricant choice takes weight, driving style, interval, usage, cooling(even simple vehicle airflow)... into account.
If they determined that ATF would last a 'lifetime', then there would be nothing wrong with it. Your lifetime definition might just be a little more demanding then the automakers marketing.
Easy enough to upgrade to a thicker GL4/synchromesh fluid if you think you need it. I doubt that ANY fluid will make up for parts breakage from too much HP/torque or driver abuse/foolishness. If you are overheating the fluid, then step up a grade or 2, or use a fluid cooler, or both.
Don't compare fluid experience with an 'old truck'. For example, the MT90 was by far my favorite Nissans/Mazdas/Toyotas/.... that required a GL4 75w90/sae90/80w90. I even did the 50:50 25:75 33/67 MTL/MT90 for the colder climate since MT85 was a recent product added to the catalog after all those years of diluting the 90 with MTL. But, the MT90 was a horrible winter foolish owner choice for a Toyota that required LV MT.
So, I would stick with ATF+4. If you want to go thicker for whatever reason, then use the MTL/MTF synchromesh type full synthetic fluids. Even the locally available Valvoline MT is a choice. If you tolerate the shifter change from thicker MTF/MTL fluid, then step up to the 85's at your next service.
There are plenty of SAE 50's, some synthetic that you can use:
I wouldn't jump on a straight weight, or a 90, or a conventional, if the vehicle is a cold weather daily driver or if you loan it to limpwristed friends/family/coworkers, especially in a colder climate. I'd wager that its a bit warmer here in KeyWest than in Michagrin.
Nissan/Hyundai/Kia/Ford/Mopar/GM... also have their version of 75w85's, which are definitely options.
Do you monitor transmission temperature?
Is your Cummins making a forsaken amount of power from mods?
Lubricant choice takes weight, driving style, interval, usage, cooling(even simple vehicle airflow)... into account.
If they determined that ATF would last a 'lifetime', then there would be nothing wrong with it. Your lifetime definition might just be a little more demanding then the automakers marketing.
Easy enough to upgrade to a thicker GL4/synchromesh fluid if you think you need it. I doubt that ANY fluid will make up for parts breakage from too much HP/torque or driver abuse/foolishness. If you are overheating the fluid, then step up a grade or 2, or use a fluid cooler, or both.
Don't compare fluid experience with an 'old truck'. For example, the MT90 was by far my favorite Nissans/Mazdas/Toyotas/.... that required a GL4 75w90/sae90/80w90. I even did the 50:50 25:75 33/67 MTL/MT90 for the colder climate since MT85 was a recent product added to the catalog after all those years of diluting the 90 with MTL. But, the MT90 was a horrible winter foolish owner choice for a Toyota that required LV MT.
So, I would stick with ATF+4. If you want to go thicker for whatever reason, then use the MTL/MTF synchromesh type full synthetic fluids. Even the locally available Valvoline MT is a choice. If you tolerate the shifter change from thicker MTF/MTL fluid, then step up to the 85's at your next service.
There are plenty of SAE 50's, some synthetic that you can use:
I wouldn't jump on a straight weight, or a 90, or a conventional, if the vehicle is a cold weather daily driver or if you loan it to limpwristed friends/family/coworkers, especially in a colder climate. I'd wager that its a bit warmer here in KeyWest than in Michagrin.
Nissan/Hyundai/Kia/Ford/Mopar/GM... also have their version of 75w85's, which are definitely options.
Do you monitor transmission temperature?
Is your Cummins making a forsaken amount of power from mods?
I’m in Canada but I don’t drive my truck in the winter. It will see a few weeks of below freezing temps when I’ll be towing with it up north for a moose hunting trip. My truck is stock and I drive it pretty gentle. I just ordered the delvac 40 transmission fluid. I had to order a 5 gallon pail so I’m hoping it shifts good. I bought the tds billet pto cover and I was thinking of throwing a temperature gauge in there at some point. I too used mt90 in my old Tacoma. It was in my list of potential oils to try. I’ll update my findings with the delvac 40 because there isn’t much out there on it.
Here's my opinion of the delvac 40 in the g56. I'm running 6.5 Liters. In the summer months it shift beautifully. This summer when camping on the west coast, the temperature dropped down to 12 celsius. I had difficulty switching from first to second. It comes out of gear fine, but doesn't go in to second unless you are really forceful with the shifter. Once the transmission warms up, it's great. Third gear has always been a little notch in my truck, with the stock atf, and also the delvac 40. I'm thinking there is no miracle fluid for the g56 transmission. If you want to change out your fluid for seasonal changes, you would have the best driving experience, but most of us will not do this. Do i feel Delvac 40 is protecting the transmission better? Yes i do, and i'll continue to use it for a while. I have a 5 gallon pail, so if anyone in western Canada wants to try the fluid, i'll sell you some at what i paid for it.
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