Join Date: Jun 2012
Location: Central Pennsylvania
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Re: 255/80R17s With Automatic Transmission
Thanks for the extra info esenfaust, and thanks for being kind to this new newbie, who is trying hard to pick up the jargon! What you said cements the understanding I have been gleaning from the usage context of these terms.
So what you and others have been saying about this 'hunting' of gears is really just a matter of degree then, because the phenonomen you describe occurs with pure stock setups with 265/70R17s and automatics too, right? I mean, as one approaches a hill, and tries to maintain, say, 60 mph, at some point, depending on the steepness of the hill, even the stock setup will automatically downshift? And unlike with a manual, where one has the option of lugging it to the extent one can stand it, with an automatic, one has no choice in the matter; its going to downshift whenever its internal logic tells it to? Its just more pronounced with the 255/80s due to the higher gearing caused by them, and the 'hunting' might start on a 4% grade with the 255s, whereas with the stock setup maybe not until a 5% or 6% grade?
Would not about the same thing occur with pulling a load, as Pale Rider suggested? It sounds like in his case there is a double whammy involved, as one has then the loss of power involved in the higher gearing, plus the extra load of a trailer?
The whole point of my reason for starting this thread was to inquire whether anyone thought this powerband shift and tendency to 'hunt' gears was injurious to the automatic transmission in any way, and no one has been able to address that point head on, and the conclusion I have come to is that the only 'bad' effect of the slight increase in gear ratios is this downshifting as you and Pale Rider described, and as I said, that's really a matter of degree. I've also gathered it could be helped by regearing, and I have no idea what that would cost, but it sounds expensive. Being a matter of degree, it seems folks don't get into it too much until they go a lot bigger, such as with 35s.