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Automatic transmission


Quickshift
09-21-2006, 07:16 PM
I have heard that "shifting" an automatic by using the L 2 etc. gear selectors is bad. Is this true?

If so why?

Arn't you just giving the tranny permission to shift when you go from L to 2 or 2 to D.

GreyGoose006
09-21-2006, 11:22 PM
i think it *Can* be bad on older, or weak trannies.
something about the trans locking up and it isnt designed to.
i really dont know, but thats what i have heard.

i dont think it will hurt it to put it in low or 2 if you are using it as a way of downshifting, but if you are using it for racing, it may do some damage.

again, i could be completly wrong, so dont take this for gospel LOL.

mazdatech177
09-23-2006, 09:59 AM
id say your engine is in more danger than your trans. just dont over-rev it.
if it was really bad for the trans, you wouldnt be able to manually shift your ATX

beef_bourito
09-23-2006, 01:41 PM
it's probably better for it than what a friend of mine does, he puts it in D, then when it's about to shift he quickly shifts it into neutral to let the revs go up, then shifts it back into D. I doubt his car will last more than a year or two more.

curtis73
09-25-2006, 01:10 AM
In general, trannys shift when they need to based on a few hundred inputs from the computer. (or a few inputs from cables, vacuum sources, and speed in the case of older trannys) You are correct when you say that holding the tranny in a lower gear only permits it to shift up to the selected gear. Some trannys will go ahead and shift beyond what you have selected if the engine reaches a certain RPM.

As a rule of thumb, most automatics will operate normally in whatever gear you put them in, its just that they stop shifting up at the gear you've selected. There is probably no damage being done unless the engine is suffering from spinning at too high an RPM.

Most modern computer controlled trannys also have fail-safe stuff built in, so while shifting manually might add a bit more stress I wouldn't worry about it. Additional wear might be noticed at the CV joints or U-joints, but the tranny itself should be fine.

Quickshift
09-25-2006, 07:08 PM
As Soon as I saw Curtis had answered I knew my question would be totally answered. Thanks for all the responses

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