Auto Transmission, manual downshifting hard on trans?
09-01-2003 | 09:06 PM
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Auto Transmission, manual downshifting hard on trans?
Is there a downside to frequent manual down shifting with the 3 or 4 speed?
Are the internals going to take it?
I recall that the first years of the GM Turbo Hydramatic 400 showed premature wear if downshifted manually. There was a running change which fixed the problem.
Is the 'Benz trans built for it?
Are the internals going to take it?
I recall that the first years of the GM Turbo Hydramatic 400 showed premature wear if downshifted manually. There was a running change which fixed the problem.
Is the 'Benz trans built for it?
09-01-2003 | 10:47 PM
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Excerpt from Vic Elford "Porsche High Performance Driving" on shifting with Tiptronic. I am going to assume that it applies to automatic transmissions.
"You already know that when changing up you can do so at full throttle with just a "tip" forward on the gear lever so that there is no lost time in acceleration. When you are changing down you will find that you can actually feel the electronic contact as you "tip" the gear lever backward. The "blip" should be done at precisely that moment to balance engine and transmission speeds. It might take a little time to develop the feel that electronic contact because it is very delicate, but it is there."
I find this to be true of the 4 speed MB automatic. You can, at the right moment, speed up the engine to match the transmission speed when downshifting to ease the load on the tranny. Also if you practice braking with the left foot, you can effectively recreate the heel and toe effect while trail braking. Takes some practice, which I ain't perfected myself as the left foot isn't near as smart as the right.
"You already know that when changing up you can do so at full throttle with just a "tip" forward on the gear lever so that there is no lost time in acceleration. When you are changing down you will find that you can actually feel the electronic contact as you "tip" the gear lever backward. The "blip" should be done at precisely that moment to balance engine and transmission speeds. It might take a little time to develop the feel that electronic contact because it is very delicate, but it is there."
I find this to be true of the 4 speed MB automatic. You can, at the right moment, speed up the engine to match the transmission speed when downshifting to ease the load on the tranny. Also if you practice braking with the left foot, you can effectively recreate the heel and toe effect while trail braking. Takes some practice, which I ain't perfected myself as the left foot isn't near as smart as the right.
09-01-2003 | 11:57 PM
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GT Jackson is right with that quote. With a bit of practice you can get downshifts in the automatic 928 to rival those of a competant 5-speed jockey. 
Made a few passengers blink too, I want you to know!!
Made a few passengers blink too, I want you to know!!
09-02-2003 | 01:28 AM
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Just for comparison...
From the '81 glovebox manual for the 3-speed transmission:
Position 2 should only be used to 95 mph... only shift down into driving range "2" when the speed is below 80 mph. It is not necessary to let up on the accelerator.
Position 1... should only be used up to 65 mph... Only shift down into "1" when the car speed is below 45 mph.
I've only recently braved keeping it in first gear - where I know I won't be going faster than 60 - it's a rush! Incredible reponse and superfast deceleration.
From the '81 glovebox manual for the 3-speed transmission:
Position 2 should only be used to 95 mph... only shift down into driving range "2" when the speed is below 80 mph. It is not necessary to let up on the accelerator.
Position 1... should only be used up to 65 mph... Only shift down into "1" when the car speed is below 45 mph.
I've only recently braved keeping it in first gear - where I know I won't be going faster than 60 - it's a rush! Incredible reponse and superfast deceleration.
