Transmission Shifting Best Practices

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mbacfp

mbacfp

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Hello all,

A few years before I joined here, I read a post about shifting with automatic transmissions. My Mazda CX-9 would shift hard (at times) when going from Reverse to Drive. Since reading that post where the recommendation is to go into neutral before going into drive has really smoothed the shifting (when going from R-N-D or D-N-R. Want to say thanks for that advice.

Question, is that standard best practices with shifting in automatic transmissions? I know in my 2003 Dodge Durango the transmission pump doesn’t run while in P, thus shifting to Neutral before shifting to R or D helps get the oil going. Curious if I have been missing something all these years.

Thanks,
 
When I was driving my parent electra225 C Body with the turboHydramatic 400 in the mid 70's, the main advice was don't put it in reverse if you are going forward faster than 40mPH or you would wear out your rear tires prematurely.


ALWAYS: Footbrake> parking brake> park. And don't shift from D into N at a stop.
 
"ALWAYS: Footbrake> parking brake> park. And don't shift from D into N at a stop."

Okay I'll ask. Why? I do it all the time at long stops. Many modern transmissions do it automatically now.
 
Originally Posted By: ARCOgraphite
When I was driving my parent electra225 C Body with the turboHydramatic 400 in the mid 70's, the main advice was don't put it in reverse if you are going forward faster than 40mPH or you would wear out your rear tires prematurely.


ALWAYS: Footbrake> parking brake> park.


Maybe on hills it might have benefit but I never use the parking brake when it's fairly flat. I know my wife has never touched the parking brake on her Rav4.

I think the AT is smart enough that you don't need to touch it at red lights to put it in neutral.
 
Modern automatic transmissions are fully computer controlled. The shift handle is just a means for the driver to offer suggestions.
 
I come to a full stop before changing direction. When selecting a direction, from park or when changing from Drive to Reverse (or vice versa) I try to wait until the trans actually is in gear before hitting the gas (my Camry seems a bit slow first thing, so I need to pay more attention now). In both cases, no sudden slamming of parts.

Underway, I sometimes will force a downshift before climbing a hill, so as to prevent a downshift under power. Some cars have good communication between engine and trans, and will cut power for this event; those vehicles don't need to do this. I don't believe my Tundra has that feature, quite certain my Camry does not.

Often I will select a low-ish gear and prevent upshifts if I know I won't stay in that upper gear for long. Limiting number of shifts.

But really, I suspect all of it is over the top in anything made in what, the last few years? Too much computer control. For me it's mostly a holdover from driving manuals.
 
Originally Posted By: mbacfp
Question, is that standard best practices with shifting in automatic transmissions?

On every vehicle with an automatic transmission I've simply put my foot on the brake, put it in gear, and then moved my foot from the brake to the throttle.

Don't overthink it.
 
In wife's Q5, the first 1->2 shift of the day is rather abrupt/violent. It'll get up to fairly high rpms in 1st and then slam/snap into 2nd. The car has to sit overnight for this to happen. Then, every subsequent 1>2 shift is smooth, even if executed only 10 seconds after the previous one. This is irrelevant of ambient temp.

Still not sure why this is happening, but it seems many other Q5 owners experience it, too. I keep forgetting to bring this up with the service advisor. It's difficult to replicate since the car would have to sit overnight first.

Maybe the trans fluid did not have a chance to circulate yet? Or maybe it's programming. Not sure.
 
Originally Posted By: Pop_Rivit
Originally Posted By: mbacfp
Question, is that standard best practices with shifting in automatic transmissions?

On every vehicle with an automatic transmission I've simply put my foot on the brake, put it in gear, and then moved my foot from the brake to the throttle.

Don't overthink it.


What pop said.
 
supton, be careful. I think it was a owner's manual I read that you should come to a halt before using the shifter. Even if the transmission is in first and the shifter is in Drive STILL do not shift into first- come to a complete stop.


If you want to force a gear, I suggest you use your right foot to gear down- then move the shifter.


I know its not perfect- but neither are automatics.
 
As mentioned already, today's modern automatics only require action from your right foot. The computers do all the thinking, mainly for fuel economy. Each vehicle has its own quirks. Many have a manual mode that you can use in certain situations like going over mountain passes. Sometimes transmissions gear hunt in these situations.
 
The TH400 is both mine and my dad's trucks ('85 GMC C3500 and '86 Chevy K20) commonly hit reverse very hard once warm. Dad's would hit it so hard sometimes you could hear the driveshaft ring from the jolt. That truck has 361,000 miles on it with one trans. rebuild, no rear end service. I've never made the correlation between that hard engagement and going directly from D>R, but it's possible.

As many automatics last hundreds of thousands of miles with so many different shifting techniques, I'm not sure there's any technique - within sensible limitations - that's worse than another.

I only set the parking brake on steep hills, or on increasingly gentler inclines the heavier it's loaded.
 
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tHE Nissan HAS AN OVERDRIVE OFF trigger button just at thumb position with your hand on the fat gear selector horn. This comes in handy if you are light throttle cruesing and come to a hill and you don't want to lug it at 1100 rpm. Just a lil push and the engine is at 2700 - 3000 rpm. Same if you just want a lil boost to get through a situation. Push gas and go. OTHERWISE with the CVT it would take maybe 1/4 throttle for the trans to move the engine into the fat torque range. Seems like just using the gas to modulate trans speed would waste the gas. And I'm sire it does the cars get a terrible 23 MPG ave. Pitiful. Wife gets over 32 in the Forester with a 6MT. So much for fuel efficient CVT! 17% effeciency loss through belt and pully losses!
Cant beat a planetary trans efficiency with 1:1 straight through top gear and lockup converter.
 
The Jatco CVT8 uses not only throttle position but the speed of throttle pedal depression to speed up the downshift process. I was impressed with this as before like mentioned, there is a lag with the cvt which gets scary in busy urban traffic.
 
Originally Posted By: Alex_V
The TH400 is both mine and my dad's trucks ('85 GMC C3500 and '86 Chevy K20) commonly hit reverse very hard once warm. Dad's would hit it so hard sometimes you could hear the driveshaft ring from the jolt. That truck has 361,000 miles on it with one trans. rebuild, no rear end service. I've never made the correlation between that hard engagement and going directly from D>R, but it's possible.


I have to wonder if it's worn U-joints or worn ring&pinion. Slack in the drivetrain. Something has to move in order to make the driveshaft ring--and I'm guessing with those kinds of miles it's the ring&pinion. Just a guess.

I have read of some transmissions using full line pressure when in reverse (it's modulated for shift quality, less pressure at low throttle, smoother shifts).
 
Originally Posted By: PimTac
"ALWAYS: Footbrake> parking brake> park. And don't shift from D into N at a stop."

Okay I'll ask. Why? I do it all the time at long stops. Many modern transmissions do it automatically now.


You hit the nail on the head: "Why?"
 
Originally Posted By: supton
Originally Posted By: Alex_V
The TH400 is both mine and my dad's trucks ('85 GMC C3500 and '86 Chevy K20) commonly hit reverse very hard once warm. Dad's would hit it so hard sometimes you could hear the driveshaft ring from the jolt. That truck has 361,000 miles on it with one trans. rebuild, no rear end service. I've never made the correlation between that hard engagement and going directly from D>R, but it's possible.


I have to wonder if it's worn U-joints or worn ring&pinion. Slack in the drivetrain. Something has to move in order to make the driveshaft ring--and I'm guessing with those kinds of miles it's the ring&pinion. Just a guess.

I have read of some transmissions using full line pressure when in reverse (it's modulated for shift quality, less pressure at low throttle, smoother shifts).


Possibly R&P in dad's (though the rear end never showed any signs of excessive wear) but I've checked mine in the last <3,000 mi. and it's all fine, including gear slack. Mine has a 2 piece driveshaft whereas his doesn't so that alone may change the likelihood of resonance. I seem to remember reading that hard R shifts in a Turbo can be due to slight misadjustment of a band or something.
 
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