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Using 'Slap' Shifter


acebass

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Probably won't cause you any problems, however, you are most likely over-revving (passing the automatic's computer generated shift points) which will lead to wear and tear and probably lower fuel efficiency and at higher speeds, I'm not sure of the effect on the torque convertor lockup system. The car's transmission is computer controlled and takes into account the vehicle's dynamics; load, temperature, throttle position and even AWD status. That control is programmed to provide the maximum efficiency at the highest fuel efficiency.

I'll probably start something here...it isn't my intention. I do, however, find it curious that after all the engineering put into today's highly efficient automatic transmissions that there are still folks that want to manually shift. It isn't just the DJ either, I belong to numerous RV forums and am amazed at the number of folks that complain about fuel mileage in one post and then brag about how they manually shift their automatics to keep the rpms high in the next. Today's automatic's are not your father's automatics. They have far more gears, locking torque convertors for several gears, not just one, a computer to control loading, driveshaft speed, shift points, fluid temperature and torque convertor lockup to maximize efficiency of both fuel and drivetrain action and transmission life; all without the driver doing anything. Yet, for some reason, some drivers feel that they can "out think" or "out perform" the vehicle's computer system. Most modern transmissions have the "manual" option, but, it wasn't intended for everyday driving; it is there for those special instances where you might need finer control of shift points where the torque is more important than efficiency or wear and tear. I've used the manual option in both the DJ and my RAM where I wanted to keep the rpm and torque high for pulling, in special circumstances, but, as soon as possible, I went back to the automatic mode. I'm old, I guess, and the rowing of gears has lost its glamor for me...I can't out think or out perform the computer manually, so, I let it do as it was designed. Like I said, I'm not trying to start anything...if you like rowing gears, by all means continue, but, it still makes me scratch my head at times.

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AS far as wear and tear, yes you will get that if used the manuel shifing for long periods of time(especially leaving it in higher RPM's). Using it here or there not so much. Other than using it for passing, towing, or acceleration onto highway, i personally do not use it. Like said above the modern automatics are far supior then they used to, but if used or abused regularly then somethings bound to happen.

There is a guy here who was saying his DJ will only shift into 6th gear if using Manuel shifting, no matter the speed on the highway it would stay in 5th. That i think needs to go back to the dealer to check it out, but i do see where that guy is coming from using Manuel til they "fix" his issue. MY R/T shifts just fine on the hwy, and it was the same year as his. Rob, i see you have a 14' so drive it liike you stole it enjoy because you have the warrenty. If anything may arrise...

Does any one know the break in period on the DJ RT? i like when VVT opens up when @ WOT...

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I assume you are talking about the "auto-shift" tranny. While I don't use it much, I do use second gear to start in the snow at times, and will use it to downshift when exiting the highway at times (saves on the crappy brake system ;) ). Accorcing to my owners manual, the computer will not allow you to shift into a gear that will damage the car. Of course you can shift from 3 to 1, but the car won't react until rpms are safe, so I am told....

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As far as the Autostick feature is concerned - try not to worry about excess wear on the components. That was figured into the design of the transmission itself. One thing that remains a relative constant with regards to the transmission's operation is something called the Clutch Volume Index (CVI). In very basic terms, the CVI value represents the volume and pressure of the transmission fluid as applied to a clutch pack in order to execute an up- or downshift. When Autostick is used, the Transmission Control Module calculates the CVI necessary to execute the selected gearshift the moment the driver selects the given gear, as opposed to the TCM performing that operation when it schedules the shift rather than the driver. Simply stated, the forces applied to the clutch packs are essentially the same regardless of whether the TCM or the driver selects the gear.

I rarely use the Autostick in my Journey due to the ergonomics of the gear lever. It is not a natural feel for me and requires a bit more effort than I care for. Plus, the extra gears in the transmission kind of negate the need - there always seems to be a gear suitable for the speed. My 300M is another story. The gear lever falls easily to my hand, and it is only a four speed. I like shifting that car manually around town - it makes it more responsive coming out of turns and cruising at lower speeds. I don't use it all the time, but quite often. The car has 289,000 miles on it and shifts perfectly to this day. Granted, I've changed the transmission fluid and filter a bunch of times over those miles, but Autostick use has had no effect on its reliability thus far.

Edited by Journeyman425
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quote:

the ergonomics are just perfect for my needs.

The problem with the ergonomics is me - I'm not very tall and sit closer to the wheel than most others. This forces my arm position somewhat backwards in order to grip the shifter comfortably. It would be perfect for me if I could move the seat back a few inches. The shifter in my 300M is further forward relative to the seat so it falls naturally to my hand. With the seat all the way back in the Journey the lever is perfect in my hand, but then I'd need blocks on the pedals!!

Edited by Journeyman425
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The problem with the ergonomics is me - I'm not very tall and sit closer to the wheel than most others. This forces my arm position somewhat backwards in order to grip the shifter comfortably. It would be perfect for me if I could move the seat back a few inches. The shifter in my 300M is further forward relative to the seat so it falls naturally to my hand. With the seat all the way back in the Journey the lever is perfect in my hand, but then I'd need blocks on the pedals!!

You stand tall on this forum!!!

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Sorry for all the duplicates on this page - I replied to a post earlier on my iPhone and messed something up! Can one of the moderators delete the blanks? Can I do that? I tried to delete them using the editor but did not find a way.

I don't have the ability to delete posts. It's only a couple. No worries.

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Hey, folks!

Thanks for the replies to my question. This is really my first automatic tranny, so I miss the stick. I have been using it to downshift, rather than hit the brakes, and on the highway when I need a little more acceleration. It is true that I rev the engine higher when I'm shifting manually.

I guess I can have faith in the auto tranny and try to let it do the work. Thanks again for your help.

Rob

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