What is good for the automatic transmission?

[mjoekingz28]

The question is for your everyday average street car/truck.


Would a fast and firm shift lead to reduced transmission failure and prolonged service or a slow and cushy shift?


I have ridden in a few vehicles that would just jam the next gear. It was nice how direct it was, but I have always worried it was about to fail.

 

[hypervish]

If the shifts are cushy and slow then it won't last as long as a transmission with firm and hard shifts. When the transmissions shifts slowly, it works the clutch bands to give you a nice even shift.

I wouldn't worry about it though, I gotten over 300,000 miles from all of my automatics and they all provide smooth shifts, you can't even tell that it shifted into a different gear. All of my cars were Japanese though. All of the domestic cars I've owned never shifted all that smoothly, and one of them still lost it's transmission at 30k miles, and then again at 80k miles.

In the end it really depends on the design.

 

[mechtech2]

Faster firmer shifts should result in longer band/clutch life from a trans.

 

[Chris142]

Originally Posted By: mechtech2
Faster firmer shifts should result in longer band/clutch life from a trans.
With the expense of U-Joints and rear end gears. I just had to RNR the rear driveshaft on my boss's K5 blazer because the yokes in the driveshaft were oblonged due to the rough shifting 700r4.

 

[HM12460]

For your average street car/truck, the best thing you can do is keep the transmission from over heating and keep it serviced as per the manufacture recommendations.

 

[The_Jeff]

And cut the power during the shift. Drive by wire cars are good for this but even in the 90s they'd retard timing for a split second.

 

[Kiwi_ME]

Even though the shift kit makers have always told us that fast shifts = less wear, I'm sceptical. Is not the energy transfer through the clutch or band to change the speed of the rotating mass (engine, TC, etc.) the same, whether fast or slow?

 

[The_Jeff]

^ true, but the time spent with the clutch half applied, or two clutches/bands applied at the same time, or both, can be cut down. Rode a city bus that surely had a "shift kit" from the get-go and was nice and firm.

 

[cchase]

Most of the torque management in new cars, I can't imagine much wear occurs even on soft full-throttle shifts. On many newer cars you can really feel the car back off during the shift - feels great. Probably not the greatest for 0-60 though.

 

[morris]

i put a hard shifting shift kit in a 727 once. well the under size rear end split the spiders at 112,xxx miles. so yes you CAN make it shift TO hard. for race MEANS RACE ONLY

 

[stranger706]

Originally Posted By: cchase
Most of the torque management in new cars, I can't imagine much wear occurs even on soft full-throttle shifts. On many newer cars you can really feel the car back off during the shift - feels great. Probably not the greatest for 0-60 though.


Haha my Fusion really does this. During normal driving it shifts like an old lady driving a manual: accelerate...pause...shift, accelerate...pause...shift.

However under full throttle it shifts completely different. No pausing at all just smooth, quick shifts with no break in acceleration. Crazy...

Our Explorer seems to shift the same regardless of the situation.

 

[SteveSRT8]

Originally Posted By: cchase
Most of the torque management in new cars, I can't imagine much wear occurs even on soft full-throttle shifts. On many newer cars you can really feel the car back off during the shift - feels great. Probably not the greatest for 0-60 though.


On some platforms, like one of my Silverados, it can make a huge difference. On others, like the SRT8, virtually no difference.

Depends on the makers strategies.

 

[CBR.worm]

There has to be a balance, but as was mentioned before, with modern torque management the wear on driveline parts is significantly reduced - so they can use smaller/ligher parts and have the same failure rate.

I would say the quicker and smoother the shift, the better. It's not like the old days where the bands and clutches were cooking during a shift with full engine power.

 

[lexus114]

Too harsh of a shift isnt good for the rest of the drive train.

 

[mechtech2]

Originally Posted By: Chris142
Originally Posted By: mechtech2
Faster firmer shifts should result in longer band/clutch life from a trans.
With the expense of U-Joints and rear end gears. I just had to RNR the rear driveshaft on my boss's K5 blazer because the yokes in the driveshaft were oblonged due to the rough shifting 700r4.


But is that for sure the cause? It is not a known problem with hard shifting transmissions. C'mon... rear ends going out?