forgive me if this is a silly question, but ....

is it inherently bad for an automatic transmission when it makes a gear change? I understand that shifting gears is what they do and why we have them, and I understand that shifting gears makes heat. What i'm wondering is, assuming that the frequency of shifting (any frequency) doesn't create a heat problem, is the shifting bad?

I've always been of the opinion that a transmission that shifts often, such as the 6r80, is needlessly "wearing itself out". that is to say, a transmission that never had to shift gears would last longer than one that did.

that being said, i'm trying to learn.

perhaps excess shifting will always create a heat problem, and one just needs to watch the temperature to know if it is shifting too much? is it possible to have enough cooling to where frequent shifting won't create too much heat?

part of my questions comes from growing up with the early generations of overdrive transmissions (AOD's) and then driving a f150 with the 6r80. the f150 shifts a lot, far more than i was used to, but it never seems to have problems with getting too hot, leaving me to think that maybe the shifting by itself isn't really a problem, but only the heat.

 

as a general rule there is some slipping that goes on during a gear change.if there was none at all,then the trans would bang into each gear and be miserable to drive.the small slippage does produce a little heat.
to help combat this little bit extra,you can install a shift kit to reduce the amount of slipping during the shifts.however it's very miniscule.this isn't anything the trans cooling system doesn't take care of.
a shift kit is good to help reduce the slipping between gear changes to help increase longevity much more so than reduce heat.

the big thing you want to watch out for with an auto trans is gear hunting.if it's shifting back and forth then your reducing trans clutch life and generating needles heat.simply lock out od,reduce or increase your speed for the load and terrain so it doesn't happen.

 

Yes, shifting is bad. The same way that running an engine is bad. Wear happens.

As clutches or bands apply and release there is some slippage. That's unavoidable. It does create heat and wear. If the trans was designed properly the cooling system will remove the heat and the wear will be manageable so that the trans has a long life.

If the trans is shifting too frequently the cooling system can't get the heat out of the friction material fast enough and the clutch burns.

Shift kits are becoming outdated technology. Back when the transmission was hydraulically controlled they were the only way to firm up shifts. Now many transmissions don't even have a valve body, so there is nowhere to install a shift kit. It's all done electronically.

 

so is the temperature a good way to gauge when it is shifting too much?

 

Yes and no.
Temperature will rise on a long pull uphill or carrying a load, into a headwind produces extra heat.

But a good cooling system should look after it.

 

It's an indicator, but not always a good one. If it shifts very frequently the clutch/band can burn up before the total trans temp gets very hot.

 

so how does one know that the transmission is shifting too much? that is to say, how frequent is too frequent?

 

That's very subjective. I consider twice a minute if my speed isn't changing to be shifting too often.

Shifting too often isn't as big of a problem as it used to be. One of my friends invented some software that prevents it. He (and Ford) hold a US patent on this software. It's been very effective.

It looks at the current throttle, speed, engine speed, acceleration, and gear, and predicts what would happen if the trans upshifts. If it predicts there will not be at least as much acceleration in the higher gear it won't upshift.

 

that's partly what I was driving at by asking the question. I've always considered "every little hill" as too often, but I have no basis for that other than what you read on the interwebs and a gut feeling. I felt comfortable with that, but after driving my 2010 at work and having no control over the shifting what-so-ever, it made me question "how much shifting is too much" because the 6r80 shifts quite a bit.



interesting to know. I wish, however, that there was a way that it could look at how many shifts the vehicle made over the last "x" minutes and determine if an upshift is
really warranted, or whether a downshift shortly thereafter is to be expected.


My experience, again with the 6r80, is that it rolling terrain will upshift to 6th on every downhill, and downshift to 4th on every uphill while towing, where if it would stay in 5th, a shift wouldn't likely be required on most of the hills.


that being said, what I also find interesting, is that it will hold 5th at 55-65mph if you drive with your foot, but the second you set the cruise it will upshift to 6th and begin the 6-5-4-5-6 shuffle on the short hills. Again, In 2009-2010 there is no provision to lock out any gears, other than holding 1st, 2nd, or 3rd, which doesn't work well at highway speeds.


but, I'm not nearly smart enough to write a program to make that happen, so I guess I have no room to complain.


"a couple times a minute" is a better guideline than I have ever heard before, so thanks for your opinion on that.

 

I can put my 2013 F150 FX4 into manual mode and force it to stay in a gear.

 

Select Shift became available in the F-150's in Model Year 2011 with the introduction of the new engine lineup, but was not available in 2009-2010.

if you have a 2011-2014 F150 and got one of the two factory towing packages, then you have select shift. unfortunately, if you weren't paying attention and picked a truck without the factory tow package .... no select shift, and no ability to control the gears what-so-ever (which really stinks, i think).

 

Ok...mine has the factory max tow package. I didn't know it was part of that option.