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G56 gear fluid

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Amsoilman, on page 1 of this thread, CKelly1 suggests using a 50/50 mix of SAE5-30W synthetic synchromesh and SAE50 synthetic Synchromesh. I found P/N: MTFQT-EA on AMSOIL's web site. The other straight weight manual transmission fluids listed don't say synchromesh and are not available in less than a 5 gallon pail. Can you recommend something to mix with the SAE5-30W synthetic synchromesh (P/N: MTFQT-EA) that will be compatible? I just need a total of 8 quarts. Thank you.

I can not recommend anything but the (MTF) MANUEL TRANSMISSION FLUID, as this is the fluid that has been designed for the NV-56 Transmissions, and does meet/exceed the specifications of the NV-5600 Transmissions.

I can not recommend or suggest you use two different fluids/viscosities to come up up something that you or C KELLY1 may think is better. One must realize, that when lubricating fluids are formulated for a specific application, all of the ingredients are blended together to make the final product, and then tested in the laboratory and then they are field tested. When one puts differing fluids/viscosities together the outcome could become disastrous, as the chemicals may work against each other. Sometimes a person can get away with it, and sometimes they can't.
 
Amsoilman,



The question about transmission oil is what to use in the G56 since Dodge only recommends ATF+4 which as the previous 6 pages of this thread indicate is not the best choice.

I fully agree that mixing two different oils might not work well due to differences in additives, etc.

View attachment MB Spec_231_2.pdfView attachment MB 235.1 - Gear oils (Specification 235.1) - Mercedes-Benz Specifications for Operating Fluids.pdf

I found a web site, www.bobistheoilguy.com, and was able to find the two attached (hopefully it worked) specifications namely,

MB235. 1 and MB231. 2 which seems to indicate that an 80W oil is what should be used in the G56 and the other spec shows approved manufactures.

The only US manufacturer I see is Mobil.



So the question now is does Amsoil have an oil for the G56 that meets MB231. 2 and MB235. 1?
 
Amsoilman,
Is the product you are referring to # MTGQT-EA? 75-90

(MTGQT-ea) is a 75W-90 API-GL-4 "MANUAL TRANSMISSION & TRANSAXLE GEAR LUBE" that meet/exceeds the specs. for a "NV-4500" transmission, and not the "NV-5600" or the "G-56+ Transmissions.
 
Amsoilman,

The question about transmission oil is what to use in the G56 since Dodge only recommends ATF+4 which as the previous 6 pages of this thread indicate is not the best choice.
I fully agree that mixing two different oils might not work well due to differences in additives, etc.
View attachment 86036View attachment 86037
I found a web site, www.bobistheoilguy.com, and was able to find the two attached (hopefully it worked) specifications namely,
MB235. 1 and MB231. 2 which seems to indicate that an 80W oil is what should be used in the G56 and the other spec shows approved manufactures.
The only US manufacturer I see is Mobil.

So the question now is does Amsoil have an oil for the G56 that meets MB231. 2 and MB235. 1?

The ATF+4 Transmission fluid does not meet the MB231. 2 or the MB235. 1 and was never intended to meet that specification! Dodge recommends the ATF+4 in the G-56 Transmissions, and are warrantied by Dodge, and not Mercedes-Benz If the vehicle is under warranty, and you have problem with the transmission, don't expect to get Dodge to cover it if you have the wrong fluid in it! 80W-90 GEAR LUBE is a GL-5 fluid, and has an (EP) EXTREME PRESSURE additive, where an ATF+4 Fluid does not have those additive in it.
I hope this helps
 
Amsoilman, CKelley1 runs a fleet of G56's and has both versions as well as both engines with hundreds of thousands of miles combined. He mixes it because the 50wt is too thick, and he runs them in cold weather. I originally went with the MB oil and paid $200. 00, only to dump it because it was attacking my syncros. The performance of the CKelley1 oil is a lot better than what was in it. As far as warranty, your right about that, and I don't recommend anyone change to the other oil and should stay with ATF, if still under warranty, but you better overfill it by one qt.
 
Amsoilman, CKelley1 runs a fleet of G56's and has both versions as well as both engines with hundreds of thousands of miles combined. He mixes it because the 50wt is too thick, and he runs them in cold weather. I originally went with the MB oil and paid $200. 00, only to dump it because it was attacking my syncros. The performance of the CKelley1 oil is a lot better than what was in it. As far as warranty, your right about that, and I don't recommend anyone change to the other oil and should stay with ATF, if still under warranty, but you better overfill it by one qt.
Oh and I forgot to add to the fact that those miles are at 40K GCVW in the mountains.



LHirshman below is a quote from CKelley1, when I contacted him asking for advise. I asked him about the noise the G56 makes, when I replaced my DMF with a SMF. You can PM me if you want to talk about why I chose the concoction.





"Steve the aluminum and the oil conducts heat so good that no mater where you place the probes they are going to read the same. all of my g56's sound that way. if you have a heat shield between the cooler and exhaust the air passing between then will keep the heat from entering the cooler. the 50 weight oil i use meets roadrangers specifications for there 700,000 mile warranty with 500,000 mile change interval. one 13 speed of mine has over 4,000,000 miles on it with one change when i lost a seal on the pto. since i live in a cold area i had to blend a lighter oil with the 50 for easer shifting. the oil additives are what makes the oil so good against wear. i spent a lot of time and money checking the additives of the lighter oils to find one that had the same exact additives. blending two oils that have different additives can be bad. interestingly the penzoil has the exact same quantity of the same additives as the 50wt, the only reason i did not use it, it was not synthetic oil base. since temp for you is not a problem just stay with the 50 wt. fill the g56 until it runs out the plug and then add 1 to 1 1/2 quarts more. you must do this to lube and cool the front bearing. here is a paste of the oil spec i use for both, as long as your oil is a equivalent to the dello spec you are good to go. attached is a pix of a truck i bought in north Carolina gvw was 39,600 lbs. 3,200 miles round trip. I regularly have 44,000 lbs gvw in the mountains and no g56 problems. "
 
Amsoilman,



It seems that everyone on this site has their own opinion about which is the correct fluid for the G56.

My truck has 102K miles so I am not concerned about a warrantee.



I have also used ATF and engine oil in manual transmissions in other vehicles I have owned without issue. Of course these were not heavy duty trucks.



I have used in my Mazda Miata, Amsoil Series 2000 75W-90 TGR-QT, in the manual transmission and Amsoil SAE80W-90 AGL-QT in the rear end.

Both are GL-2 to GL-5 spec. These oils have been used for 85K miles with no problems. Warrantee issues aside which one of these non MB/Chrysler recommended fluids would be the better choice for me? I absolve you, your assessors and assigns and AMSOIL, from any responsibility now or in the future with regard to your advise.
 
Amsoilman,

It seems that everyone on this site has their own opinion about which is the correct fluid for the G56.
My truck has 102K miles so I am not concerned about a warrantee.

I have also used ATF and engine oil in manual transmissions in other vehicles I have owned without issue. Of course these were not heavy duty trucks.

I have used in my Mazda Miata, Amsoil Series 2000 75W-90 TGR-QT, in the manual transmission and Amsoil SAE80W-90 AGL-QT in the rear end.
Both are GL-2 to GL-5 spec. These oils have been used for 85K miles with no problems. Warrantee issues aside which one of these non MB/Chrysler recommended fluids would be the better choice for me? I absolve you, your assessors and assigns and AMSOIL, from any responsibility now or in the future with regard to your advise.
You are certainly free to use any fluid you so desire in your vehicles. I am simply stating what the Manufacturer requires for warranty purposes.
 
The ATF+4 Transmission fluid does not meet the MB231. 2 or the MB235. 1 and was never intended to meet that specification! Dodge recommends the ATF+4 in the G-56 Transmissions, and are warrantied by Dodge, and not Mercedes-Benz If the vehicle is under warranty, and you have problem with the transmission, don't expect to get Dodge to cover it if you have the wrong fluid in it! 80W-90 GEAR LUBE is a GL-5 fluid, and has an (EP) EXTREME PRESSURE additive, where an ATF+4 Fluid does not have those additive in it.
I hope this helps

This is true. However, Dodge is only concerned with beating the odds on getting the transmission through (and better yet, slightly through) the warranty period.

I have 103k miles on my '06 G56. I used EXCLUSIVELY the Amsoil ATF fluid, changing on about 25k mile intervals. I have a transmission temperature gauge installed, and have never exceeded 215° F, and rarely over 180° F. That being said, at 103k miles, I lost 4th and 6th gear in my transmission. Of course, it ruined the countershaft as well. I've been saving money now for 2 1/2 years to try to get this transmission fixed, while the truck has sat idle :(. This is the sole reason that I've not hardly frequented this forum in the last couple years in the 3rd Gen section. In researching this issue, I'm finding I am not among the minority, in that I've had a G56 failure shortly after the 100k mile mark.

In the past couple years, I've been doing a lot of reading. While running ATF wasn't the sole contributor to my failure, I do believe it was one of the contributors. There is very little "cushioning" ability of the ATF to prevent metal-on-metal gear tooth impact, like there is with an EP lubricant. I'm looking forward to the TDR information, but I hope it's a lot more in depth that just a condensed reprint of the information that's already been available on the web for the past year or two. Has anyone contacted Mike at Lazarsmith regarding the "concerns" with his oil as stemming from Flopster's oil analysis? I ask this, because a tribilogical analysis is only a small part of the story. Sure, they can look for a handful of certain compounds or chemical species that have commonly been used to provide various desirable properties; however, there are a lot of other emerging technologies that offer MUCH better performance in lube oils than the traditional 75-year-old-well-accepted additives for wear prevention, anti-foaming, lubricity, etc, etc. A run-of-the-mill oil analysis is not going to pick up these compounds at all, and could very well give credence toward one forming a wrong opinion on an oil's performance!! I understand Flopster did what he could with a limited budget... and he did an outstanding job at what he did. I'm glad his work is going to be published in TDR. However, the lube oil and ad-pac industries are one of the most secretive operations in existence. Lubrizol, for example, has developed some incredible formulations that offer anti-wear and lubricity properties like nothing we've ever seen; however, to have this lube tested by Blackstone, etc, one would deem it unsuitable for use based on viscosity and "common" elemental analysis.


Wayne,
Does Amsoil have the ability to perform 4-ball wear tests in house? Or sliding friction wear test? If so, do you have access to this equipment? It would be very interesting to include wear analysis results with the oils in Flopster's research.


I think it's clear that the Daimler-Chrysler merger did nothing in the way of improving the reliablity of our Dodge/Cummins trucks, at least as far as the manual transmissions are concerned. I know these are just rambling thoughts, but I still feel like there is not detailed enough information (at least that I've seen) to make a really good decision on what oil to use in the G56. For every argument, there seems to be a discending experience/opinion.

Has anyone ran Gorilla Juice in a G56 for an extended time (more than 100k miles) and experienced a failure that could be linked to the fluid? (I'm aware some people find the transmission harder to shift, some people find gold flake particles, etc, etc... but these are not failures).

Has anyone ran the Mobil 50 wt fluids for an extended time (more than 100k miles) and experienced a failure that could be linked to the fluid?

Just one more rambling thought... my parents have a 2006 Jeep Liberty with the NSG370 transmission. This is a Daimler inspired transmission that they began putting into Chrysler vehicles after the merger, very similar to our G56s. My parent's transmission just got rebuilt last week (out of warranty) at 72k miles. This is not an uncommon occurance for these transmissions either :(

--Eric
 
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I just had the flywheel, clutch, pressure plate, etc. , replaced with a single disk SBC unit. After making this appointment I received the Email about what's in Issue 81. Of particular interest was the G56 fluid article. I would like to thank Robbin Patton and Bob Pinkowski for Emailing me a copy of the article. Getting the article allowed me to order the Mobil Delvac Synthetic Transmission fluid 50 in time for the SBC clutch installation.

Auto Wurks Diesel in Caldwell, New Jersey, performed the installation. They are methodical and test drove my truck after the clutch installation but before changing the fluid. Once they were satisfied they then changed out the ATF and put in the Mobil Delvac. They were very impressed with the difference the Mobil Delvac made to the sound of the transmission. Other threads indicate the new sounds one can expect when replacing the DMF with the SBC system. I drove the truck home (about 63 miles) and I have to say the transmission was quiet, shifted smoothly and felt like it did when it was brand new 102Kmiles ago.

My opinion is, this is the correct fluid to use if you are not under warranty. We'll see over time and as the temperatures cool down if any issues arise from using the Mobil Delvac. I'll keep you all posted.
 
Glad to hear your truck is doing great, and mobil delvac oil is a good choice. When the cold temperatures of NY start, you might find the need to thin it out with the Royal Purple. What I do when warming up my truck, is shift the transfer case into neutral and let it idle in forth gear. If your truck doesn't have the high idle feature like my 04. 5, I fabricated an adjustable rod and saddle for the throttle pedal and used that. You don't want to idle a 5. 9 Cummins for extended periods.
 
If you read the just out TDR there is an article about this very subject and it tells just how RAM/Chriysler came to use ATF in the G56. The manufacture does not recommend it. It is a very good article. I currently use Penz Syncromesh in mine. Just changed it last yr. Ck out the TDR article and get your answer.

DClark
 
Sorry guys, My mistake. It is an article about engine oil changes, but I did read a thread about this with tests by a testing lab on the various transmission fluids and it is not ATF that is recommended. I don't knnow where the thread is at this time.
DClark
 
Well well well, now that the transmission has been inspected and the DMF has been replaced with a SMF with a SBC DDS 3250 clutch and I have 600 miles on the Mobil trans SHC DC, MB recommended oil, I dumped it and saw light gold flakes in the oil which should indicate that the synchronizer's didn't like it. So I'm going to go with member CKelley1 recommendation, which he has been running for a very long time and heavy towing miles. His oil blend is the Mobil delvac transmission 50 sae fluid and Royal Purple synchromesh, at a 50/50 blend. The trans runs close to the same temperature with the SHC DC or Pennzoil synchromesh in it, at @ 200*. The pennzoil synchromesh seems too thin and is not a synthetic oil, and at the high temperature the G56 seems to run at, that have been reported, have a wide range from 180* to 250* should require a synthetic. Knowing that CKelley1 has lots of miles on his blend, it will be the last oil my trans will see, I'm going to stick with it for the long haul.
http://www.carbonitecummins.com/Documents/Trans Oil Comparison.pdf



Read this before you spend your hard earned money, I love the comparisons but spent my hard earned money and dumped the oil.
 
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