Forum Discussion
ShinerBock
Sep 09, 2019Explorer
If you had an Duramax with an Allison, then you might be disappointed going to the Aisin or 68RFE. The Aisin is a slow shifting and clunky trans, and the shift logic is not as good as the Allison. However, it is a more stout trans with a PTO. The 68RFE shifts quicker and much smoother than the AIsin, but still not as good as the Allison in its shift logic. The most that can be towed with the 68RFE is 22k.
The other major difference between the two is compression ratio of the engine each comes with which will effect fuel economy. The Cummins with the Aisin has a lower 16.2: compression ratio which is needed to attain higher 400 hp and remain emissions compliant, but will have less fuel mileage in comparison. The Cummins with the 68RFE has a compression ratio of 19.0:1 and makes 370 hp, but will have better fuel economy. It just depends on which is more important to you.
The other major difference between the two is compression ratio of the engine each comes with which will effect fuel economy. The Cummins with the Aisin has a lower 16.2: compression ratio which is needed to attain higher 400 hp and remain emissions compliant, but will have less fuel mileage in comparison. The Cummins with the 68RFE has a compression ratio of 19.0:1 and makes 370 hp, but will have better fuel economy. It just depends on which is more important to you.
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