Originally Posted by dodgetank
Hello! This is my first post here. I just bought a 2013 ram sport 8spd with the "3.55" rear end. After reading about a bunch of trucks getting shipped with 3.21's, I crawled underneath and sure enough, i've been screwed.
I was just wondering if the 3.21 rear end is weaker than the 3.55 or 3.92? Or maybe towing heavy with the 3.21 would put too much stress on the tranny?? From what you posted, it really seems like they shouldn't have downgraded the tow rating for this combo.
Before I attempt to get the stealership to give me what I paid for, I just want to make sure it's the best move. I like the 1400-1500 RPM on the highway, but I don't like the idea of over taxing my tranny or causing damage to a weak rear end.
I don't see why the 3.21 would be any weaker than the 3.55 or 3.92, but I don't know that for a fact. I don't see how it would stress the tranny out more than the 3.55 since the ratios actually favor the 8sp/3.21 combo over the 6sp/3.92 combo on the lower gears.
They may have downgraded the 8sp/3.21 combo because in the top gear (8th) it will be way down out of the power band around 1200 RPM or it might be just pure marketing. I'm guessing the rational is the same as for the 6sp/3.21 combo or 6sp/3.55 combo.
For towing you can just drop down to 7th and be at the same happy place as the 6sp/3.92 combo.
Unfortunately Chrysler isn't helping any of you make the decision and they are the ones that are setting the recommended tow ratings. If it were me I would be demanding some kinda satisfaction from the dealer. It's one thing to change how something is built as long as it is meeting the same design requirement but this change up doesn't do that.