dnewton3
Staff member
I'll throw in my $.02 here ...
Per the reference page near the top, the Ram trucks have two applications:
Auto T-case
The Mobile LT is a tractor-hydraulic fluid; it's good quality stuff. This is a typical universal tractor fluid that can be used in shared-sump systems that use the fluid for both the transionssion and the hyrdraulics. This is a very common thing in tractors and has been for decades. This is the fluid for the t-case the OP has, and I would say any good quality UTHF will work for this application.
Part-time t-case
The part-time t-cases apparently use the Shell Spirax A389 stuff; that "389" reference is a nod to the Allison "TES-389" fluid spec, which is essentially a nod to the old GM Dexron III-h stuff ( they are red-colored ATFs and the Shell product even has "ATF" in it's title). Meaning that this is essentially a lessor cost alternative (read as non-synthetic) option as a traditional automotive ATF. The Allison TES-295 is their high-end synthetic ATF spec, and the TES-389 is their common-man non-syn ATF spec. In these applicaitons (which does not include the OPs truck), just about any decent Dex/Merc fluid will suffice. A cautionary note is that GM and Ford don't license those old fluid specs and haven't for a while, and so if you use a "Dex/Merc" variant, you'll want to assure yourself it's a good product from a reputable company. For example, Mobil's "D/M' is actually an approved and licensed Allison fluid, even though "Dexron III-h" and "Mercon" are not licensed by GM and Ford. But Allision keeps the spec alive for a non-syn choice in their fluid spec line-up. Reputable companies like Mobil, Shell, Castrol, Valvoline, etc are going to make their Dex/Merc fluids to a good quality level despite a lack of the GM and Ford licenses being issued.
I am not convinced that the Amsoil look-up tool is spec'ing the right fluid for the OPs application, I think they are being generic and not realizing that there are two fluids in play here. Amsoil's site shows the same two ATF products for all three t-case applications. To me, that does not seem correct; they are ignoring the UTHF stuff. Maybe it's their opinion that the ATFs will suffice for the UTHF application? I do see that Amsoil has an agricultural section, and in there they have a "hydrostatic" trans fluid, but it's not really marketed as a UTHF; it's more of a hydrostat fluid like is used in zero-turn mowers, but it is in their "agricultural" section ... for what that's worth. Might be worth a try to reach out to Pablo for his opinon here.
I would use any decent quality UTHF. I would recommend getting a synthetic one and not having to change it as often.
Per the reference page near the top, the Ram trucks have two applications:
Auto T-case
The Mobile LT is a tractor-hydraulic fluid; it's good quality stuff. This is a typical universal tractor fluid that can be used in shared-sump systems that use the fluid for both the transionssion and the hyrdraulics. This is a very common thing in tractors and has been for decades. This is the fluid for the t-case the OP has, and I would say any good quality UTHF will work for this application.
Products
Mobilfluid LT is an extra high performance multipurpose tractor lubricant engineered to meet or exceed tractor transmission, drivetrain, and hydraulic fluid requirements
www.mobil.com
Part-time t-case
The part-time t-cases apparently use the Shell Spirax A389 stuff; that "389" reference is a nod to the Allison "TES-389" fluid spec, which is essentially a nod to the old GM Dexron III-h stuff ( they are red-colored ATFs and the Shell product even has "ATF" in it's title). Meaning that this is essentially a lessor cost alternative (read as non-synthetic) option as a traditional automotive ATF. The Allison TES-295 is their high-end synthetic ATF spec, and the TES-389 is their common-man non-syn ATF spec. In these applicaitons (which does not include the OPs truck), just about any decent Dex/Merc fluid will suffice. A cautionary note is that GM and Ford don't license those old fluid specs and haven't for a while, and so if you use a "Dex/Merc" variant, you'll want to assure yourself it's a good product from a reputable company. For example, Mobil's "D/M' is actually an approved and licensed Allison fluid, even though "Dexron III-h" and "Mercon" are not licensed by GM and Ford. But Allision keeps the spec alive for a non-syn choice in their fluid spec line-up. Reputable companies like Mobil, Shell, Castrol, Valvoline, etc are going to make their Dex/Merc fluids to a good quality level despite a lack of the GM and Ford licenses being issued.
On-Highway Fluids
Allison Transmission approved fluids are tested to meet our stringent requirements, which ensure maximum transmission durability with minimal downtime.
allisontransmission.com
I am not convinced that the Amsoil look-up tool is spec'ing the right fluid for the OPs application, I think they are being generic and not realizing that there are two fluids in play here. Amsoil's site shows the same two ATF products for all three t-case applications. To me, that does not seem correct; they are ignoring the UTHF stuff. Maybe it's their opinion that the ATFs will suffice for the UTHF application? I do see that Amsoil has an agricultural section, and in there they have a "hydrostatic" trans fluid, but it's not really marketed as a UTHF; it's more of a hydrostat fluid like is used in zero-turn mowers, but it is in their "agricultural" section ... for what that's worth. Might be worth a try to reach out to Pablo for his opinon here.
I would use any decent quality UTHF. I would recommend getting a synthetic one and not having to change it as often.
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