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We don't have a transmission and drivetrain forum, so I'll post here.

Some people are arguing manually downshifting (in my case, I tip my lever left and right for -/+) is very bad for the tranny on the highway. I do it all the time for quicker response.

Is this bad?
 

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I guess stepping on the gas until it kicks down is bad too. :hammer:

Ask them, why isn't flooring the gas pedal until it kicks down considered "bad" but manual downshifting to get the motor into its sweet spot is?

I want to hear their reasoning. The load (stress) is at the highest when the motor is outside of it's sweet spot (struggling in low rpms) and also vulnerable to ping/detonation. You invoking a manual downshift into the sweet spot actually reduces the stress on the drivetrain components. The transmission should be engineered to accept manual downshifts without any issue. It's the dumb things that will kill it (brake stands, revving in neutral then dropping into gear, etc).
 

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Actually manually downshifting is very bad on some cars. On my Buick with the 4L60, it's very easy to fry the overrun clutches which control the downshifts. So with that car I rev matched my downshifts and the original tranny lasted 78k miles (that's considered ALOT with the way I drove it). It would have gone longer if I didn't implode the tranny on a hard 1-2 shift (broke the shaft and the gears ate themselves up).

With the MB, I drive it like a stick anyway, but it rev matches on its own so I don't bother.

Stepping on the gas and having the car downshift works differently and doesn't stress the clutches like manually downshifting does.
 

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Roupin said:
Stepping on the gas and having the car downshift works differently and doesn't stress the clutches like manually downshifting does.
I hate when it does that in steptronic mode :wall:
 

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Downshifting manually per say is no different than downshifting by flooring the car. It is all about your technique. Also, keep in mind that these cars have TQ converters, so there is a lag anyway.
As long as you are downshifting and rev matching, then I see no difference in that and overall flooring. Sure, spirited driving is more stressfull on the car, but that isn't the argument, is it?
 

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Jangy, I meant downshifting cold without a rev match is bad for the car. If you can properly match the revs, drop as many gears as you like.

I occasionally just drop it in 1st at 30mph just to see what rpm I'll be running at. We all like to play around, and that's why we're here, right? :D :thumbup:
 

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i have a auto transmission, but if i use the manual mode. and leave it on first gear, and keep pressing the gas pedel. will it blow up the engine. or is there a cutoff that the car just refuse to go any faster?
 

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It will shift up at redline, in all gears forward gears.

Now I'm suspecting that I have 2 reverse gears in my car, but haven't really had a reason to run a WOT run in reverse....yet :evil:
 

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If the tranny is in Manual (M) mode it will NOT upshift automatically. Hitting the rev limiter isn't bad if you do it once in a while accidentally but doing it frequently and intentionally is another story.
 

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SDSilverM3 said:
If the tranny is in Manual (M) mode it will NOT upshift automatically. Hitting the rev limiter isn't bad if you do it once in a while accidentally but doing it frequently and intentionally is another story.
There is no such thing as a true manual mode on the non-AMG (but computer controlled) cars. You can hold lower gears manually, but it will shift up on its own at redline anyway. Trust me, I do it all day long.

As for bouncing off the rev limiter, a few miles of that on another car pretty much destroyed my flexplate. It fractured and fell apart.

The only way to get the MB to hit the rev limiter is to hold the shifter in the downshift position during a WOT run. Even then though, after about 1-2 seconds of bouncing around, it shifts up anyway.
 

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SDSilverM3 said:
If the tranny is in Manual (M) mode it will NOT upshift automatically. Hitting the rev limiter isn't bad if you do it once in a while accidentally but doing it frequently and intentionally is another story.
on my C32, when i hit redline, it'll upshift automatically.
 

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Not on my car or any of the other 55's. Once you're in a certain gear in M mode you're stuck there until a) you manually upshift or b) your shit blows up.
 

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SDSilverM3 said:
Not on my car or any of the other 55's. Once you're in a certain gear in M mode you're stuck there until a) you manually upshift or b) your shit blows up.
:clap: :eek:hnoes: :drive:
 

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SDSilverM3 said:
Not on my car or any of the other 55's. Once you're in a certain gear in M mode you're stuck there until a) you manually upshift or b) your shit blows up.
I wish my car was like that. I'm going to ask for the auto upshift to be disabled at Powerchip if they can do it.
 

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If it's a lease, do anything you want to it.

If you plan on keeping it for a while, don't do it as much...UNLESS you know what rev matching means.
 

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I am happy and impressed with my car and I do got that urge to play around sometimes, I have stopped doing the whole "Manual shifting" thing because I drive it daily and don't wanna put stress but if a fool rolls up only then will I have to go into battle mode, but other then that I use it when I need to pass people up during traffic hour at the on-ramp lights. :thumbup:

quick question, the heck is "rev matching?"
 
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