Well,according to Blackstone it's nearly identical. I thinned mine out per CKelley's suggestion with 5-30 Amsoil synchromesh. After a couple of blocks it shifts pretty well here in our climate. Excellent after warming up a bit. Now this winter maybe another matter. I believe all this speculation came about after owner's couldn't stand the racket these transmission's make after the smf conversion using ATF. Mine never shifted better than with Amsoil ATF and the stock clutch. I drained it at 21K one time and the magnet had a dab of fuzz on it and the fluid was pink as new.
I too don't see how Mercedes can specify any fluid this thick for worldwide cold climates.
On Mobil's site they say that the Mobiltrans SHC DC is discontinued has been replaced with the Mobil Delvac 50 wt. CKelly 1 who makes the Synchromax fluid? That sounds like it would be a better match as the synthetic 50 wt is really had shifting when cold... .
Correct, but the Delvac was the nearest identical to the SHC DC and as posted above "On Mobil's site they say that the Mobiltrans SHC DC is discontinued has been replaced with the Mobil Delvac 50 ".
Once I got it hot it was fine, but that's not acceptable, no way I could leave my driveway when it's 20F out. Probably work fine in the southern US, but that's about it.
Let me try to answer these points as were posted above (bearing in mind I am not a tribologist):
Let's start with what we know to be fact.
1. The G56 Transmission has only two specified fluids in the US.
A). The first specified fluid for the G56 in the Dodge Ram and Ram trucks is specified by Chrysler/Dodge/Ram. This fluid is ATF+4. Dodge specifies only 5 quarts of ATF+4 in the transmission, not 6 quarts as many say. Chrysler/Dodge/Ram also is the warranty provider for this transmission. Using any other transmission fluid or more than is specified is not recommended.
B). The second specified fluid per Mercedes Benz (MB) Specification is MobilTrans SHC DC. It is available product - we sell it. Mercedes Benz does not warranty your transmission - Chrysler/Dodge/Ram does. The MobilTrans SHC DC meets MB Spec
http://bevo.mercedes-benz.com/bevolisten/235.13_en.html. The specification is cited on the products labeling (on the MobilTrans SHC DC label) and is the only product currently sold in the US that carries this rating.
2. Delvac 50 is not a substitute for the MobilTrans SHC DC as per my conversations with ExxonMobil engineering technical support. It does not meet the MB specification, nor does it say anywhere on the product packaging that it does, nor does ExxonMobil say or imply that it meets MB specification per my conversations with their engineering technical support.
3. The Blackstone tests that were done are an excellent starting point for making your own decision if you decide to stray from the two recommended fluids. The tests, however, are not comprehensive nor complete. The cost associated with a four ball, bouncing ball, pin on disc, etc. type of test is expensive. The Blackstone tests do not measure for the others chemicals / properties of these tests and serve as a starting point only. It's adds a scientific starting point with which to begin comparisons, but is not definitive in the least.
4. On page 16 of the report by Flopster843, he concludes by saying, "But this is your truck and your bill if it breaks. Use the information here and draw your own conclusion. As for me, the only fluid going in my transmission from this point forward is MobilTrans SHC DC. "
That sums up all we can say that we truly know is fact based on published information. Please let me know if I've missed anything.
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In addressing the other issues as relating to what's above I can relate to you what I do have direct experience with. I do use MobilTrans SHC DC and I have operated my vehicle in temperatures down to 15 degrees Fahrenheit. The answer to the shifting while cold for me is to warm up the transmission while I let the engine warm up.
I would like to take credit for this idea, but IIRC, AH64ID first posted this a long time ago. I make sure my parking brake is set and will hold. I start the engine, put the transfer case in neutral, and shift into sixth gear. I slowly release the clutch and the transmission will be running at the speed my engine is idling. I warm up my truck typically five or so minutes when it's under 45 degrees Fahrenheit. When I pull away my trans shifts normally. I do shift at around 1850 to 2000 RPMs though. I have found that if I shift at a lower rpm, it does shift a little slower.
In regard to custom blended transmission fluids, it's all an individual choice. If you have questions I didn't answer here, please post here or PM me and I'll try to help as best I can.
As a sidenote - An excellent resource as a starting point is "Bob is the Oil Guy". Here's a link to "Basic Lubrication Design" and I highly recommend "Motor Oil University" that is on that site as well. It helps explain a lot of information, and helps you make a better informed decision.
http://www.bobistheoilguy.com/basic-lubrication-design/
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