AT shifting methods

[stringsattached]

I just read a post in another thread, and it reminded me of something I've always wanted to ask, but never remember to.

I know more than one person (w/an automatic transmission) who fires up their car, backs it out of their driveway, and while the car IS STILL ROLLING BACKWARDS, throws it into drive. The car usually does one of those "rubber band" launches (that's the best way I can descibe it) and off they go.

I always cringe when they do this, but I have no real reason to tell them not to, other than I can't imagine it's doing the car any good. Am I nuts?

P.S. an "official sounding" reason why they shouldn't do this would be best if there is one...

 

[ARB1977]

I feel you pain man thats why i dont do it in my truck but ive got in some cars or trucks and the transmission doesnt do what you described, i dont know.

 

[MolaKule]

IN order to reduce drivline shock, I recommend they go from reverse to neutral then to drive.

Shops just love replacing U-joints and CV joints.

 

[Tosh]

I'm hesitant to admit this, but on my car when I slip it into D while still rolling slowly backward, it feels like the transmission is coping alright. I don't believe I'm doing any damage, but then I'm doing this very slowly and deliberately and also not giving it any gas. I think my experience is no help in answering this question, right?

 

[JHZR2]

I would think it would be harsher on a MT t do this than on an auto... doesnt the torque onverter take up the 'slack' in the driveline due to rolling the wrong way?

In a rental car I once shifted to reverse while going forward at ~5mph to see what would happen... the car kept going forward for a while, then went backwards. No odd behavior except for mine for doing the test.

JMH

 

[Tom300M]

Some auto's seem to not mind the shifting to drive while still rolling back just a bit (Crown Vic/Grand Marquis come to mind, at least from the way it feels). My 300M is one that does not like it, if I do have to do it ever (like backing onto a busy road from a driveway, etc) it gives me a sort of bump which really feels detrimental to the car. I usually try to let it hang in neutral for a second or two though after having fully stopped when going from reverse to drive or vise versa.
One thing I've noticed though is that of all the different owners manuals I've read, in the automatic transmission section, the wording always seems to stress comming to a complete stop when shifting from drive to reverse, more than when shifting reverse to drive.
Still I always see friends and family members not comming to complete stops before shifting their auto trans. I've brought it up with some of them, but no one ever listens. However I haven't known anyone who ever needed a re-build or had some other type of problems, so maybe it doesn't matter that much.

 

[ikeepmychevytoo]

I did this a couple of times accidentally, nothing happened, I also think like Tosh. You may engage it while rolling, isnt it the relative speed that important for trans.? However, I prefer it rolling slightly in-direction, I use the inclination at N, especially in the mornings at high idle.

 

[porcupine73]

Given the choice, I would think that having the vehicle stopped when shifting from R to D would be preferrable to rolling backward. I've noticed in some cars the auto trans won't shift into D if it is moving more than 5 mph or so backward.

Normally on auto trans when switching from R to D after I step on the brake to stop I stay in N for a second until the vehicle has completely stopped then switch to D and wait a second or two until I am sure it has fully shifted.

I had a friend in high school who would frequently get his '91 Cavalier going about 15-20mph in reverse and then put it into neutral and floor it and then put it into drive to get the tire to squeal.