Allison Trans Fluid vs DT 12

[Wombat63]

Sorry if this has been asked and answered, but does anyone know if I can use the Allison recommended Trans fluid Castrol Transyn 668 in My 2016 DT12 auto trans?

 

[wwillson]

The data I found said the 2016 and older DT12 (automated manual) transmission requires MB 235.11, which is 75w-90. Allison TES 668 is an automatic transmission fluid that has a much lower viscosity. No you can't use TES 668 fluid in your very expensive DT12 transmission. You should use a MB 235.11 spec fluid.

 

[Wombat63]

Thanks for your reply I guess after 40 years of trucking and finally succumbing to the ease of an auto trans I'm not up on fluids, I thought that if its 75W 90 then it was the same viscosity? but I appreciate the reply

 

[Wombat63]

I thought the TES 668 was 75W but I just realized the site that said it was is probably wrong! gotta love the internet

 

[Wombat63]

So how does a 75W 90 gear oil differ from transmission oil?

 

[Duckless]

Thanks for your reply I guess after 40 years of trucking and finally succumbing to the ease of an auto trans I'm not up on fluids, I thought that if its 75W 90 then it was the same viscosity? but I appreciate the reply

It's not an "auto" in the traditional sense of transmissions. What you have is an auto shifting manual transmission. Essentially the same transmission you shifted for 40 years, with a mechanism and computer on top of it clutching and shifting for you.

 

[Wombat63]

so is it natural to assume that gear oil as long as it is 75W 90 would be acceptable to run?

 

[Duckless]

so is it natural to assume that gear oil as long as it is 75W 90 would be acceptable to run?

Provided that's what the DT12 of your trucks year calls for and it meets the specs it asks for, yep.

 

[Wombat63]

It calls for full synthetic 75W 90

 

[Wombat63]

The closest I can find is 75W 80 used in Volvo IDrives would that work?

 

[dfarr67]

Isn't there a TES 663?

 

[nascarnation]

Isn't there a TES 663?

Yes there is, but it is a specification that applies to telematics (communication between electronic devices).

https://www.allisontransmission.com/docs/default-source/supplier-quality/procurement/f11097-engineering-specification-revision-listing.pdf?sfvrsn=dcca91d_21

 

[Kantaro]

so is it natural to assume that gear oil as long as it is 75W 90 would be acceptable to run?

As explained above, you need a fluid that meets MB 235.11. Here's a list:

Mercedes-Benz Trucks Operating Fluids

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bevo.mercedes-benz-trucks.com