Talking Trucks Tuesday: Why So Many Transmission Gears?

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By G.R. Whale

Readers of a certain generation may fondly remember "10-speeds" — the upgrade bicycle from their single-speed kid's model. Those of us who know about semi-trucks know they've been using 10-speed transmissions for quite a while. And now you can get a 10-speed in a pickup truck (thank you 2017 Ford F-150), which raises the question: How many gears are too many?

Modern pickups offer five, six, seven, eight or 10 speeds while many cars and SUVs sport nine-speed transmissions. Usually trumpeted as gas-saving technology, these transmissions more often help maintain mileage while increasing performance. Interestingly, Ford's jump from a six-speed (2016) to 10-speed (2017) earned the F-150 all of a 1 mpg EPA-estimated fuel-economy increase for combined and city driving.

We think some gears seem to be simply too tall for many legal speeds or the computers aren't smart enough to figure things out. I usually can't get a Chrysler or Jeep nine-speed into top gear at anything less than 70 mph, yet I can get a Ford 10-speed into top gear in the low-40-mph range (and that's with a 4.10:1 axle gear in the new Raptor). Also, when comparing 1st gear to top gear ratios, there doesn't seem to be much difference (maybe a percentage point or two) whether you're looking at a 10-speed, eight-speed (Ram) or seven-speed (Nissan Titan).

How many gears do you think are necessary to make your pickup work the way you need it to? And where do we reach diminishing returns against added cost or lost longevity, serviceability, mileage and torque management? How many gears are too many? Does anyone still need to shift through the gears anyway? Let us know in the comments section below.

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Comments

Big rigs have more gears then these pickups. In big rigs more gears doesnt necessarily mean less longevity. Just means there are right gears for almost every situation

my guess is it is ok. Likely there is a strategy to skip un-needed gears during certain driving situations.

But if the tallest gear is still the on 6 speed vs 10 speed then why bother.

Give the high horsepower and the low rear end ratio I would expect that the Raptor would be shifting into a higher gear at a lower vehicle speed than one would see in a car. Most cars/light SUVs are going to have a steep differential gear and a lower HP/weight ratio than a Raptor.
The greater your weight to power ratio the more of a difference the number of gear ratios is going to make to you. It allows you to better keep the engine in its power band when needed and still be able to run it at its most efficient speed when full power is not needed. This is why semis often run 18 speed transmissions-and have for a long time.
“when comparing 1st gear to top gear ratios, there doesn't seem to be much difference (maybe a percentage point or two) whether you're looking at a 10-speed, eight-speed (Ram) or seven-speed (Nissan Titan).” This sentence is confusing to me. Perhaps you were trying to talk about ratio spread? The Raptor 10 speed has a nearly 11% greater spread. That’s pretty significant. It allows you to have a lower first overall ratio, run lower differential gears, keep the engine closer to its power peak and run the engine at a lower, more efficient speed while cruising.
It worth keeping in mind that in addition to increased fuel economy you also get more power from the same engine size (ability to keep engine closer to peak power), lower cruising engine speed, smoother power delivery and better take-off (lower gear ratio).
To answer the question though, I think your returns depend on the vehicle dynamics but for a truck, I would guess after 10 speeds your return on investment is pretty small. Honestly, for most ½ tons, I’d guess much over 8 is going to be pretty insignificant.

"Interestingly, Ford's jump from a six-speed (2016) to 10-speed (2017) earned the F-150 all of a 1 mpg EPA-estimated fuel-economy increase for combined and city driving."

Wow, a whopping 1 mpg increase! Whoopdiedoo!

As an owner with a 15' GMC six speed it gets better or equal mpg than some of the current trucks with more speeds than six. Now if a 10 speed truck got 30 mpg (gasser not diesel), that would garner my attention otherwise it's a waste in dollars and even more of a hassle regarding repair costs. Also will add some manufactures are still struggling with programming these transmissions to shift smoothly. J

I'm a fan of the 6 speed my Tundra has, sometimes I wish there was a gear between 3rd and 4th, but for the most part the 6 speed is perfect. Usually when towing it sits in 3rd or 4th gear and tows perfectly fine. Sometimes on steep hills it'll drop into 2nd and on flat surfaces it'll go into 5th.

Personally, I think an 8 speed is the perfect amount of gears for a pickup, 10 seems like a lot of excessive shifting. 8 speed trans would allow for a really deep 1st gear for better take off acceleration, but from what I've seen the top gear in the 6 speed/8 speed/10 speed seem to be very similar ratio wise.

I have the 8 speed in a Silverado. It takes a little getting use to when accelerating lightly. Because of the extra gears and closer spacing, the trans up shifts earlier than we have been conditioned to expect from previous 4 and 6 speed transmissions. The extra cogs certainly contributes to improved economy but the real advantage is when hauling or pulling. The transmission quickly finds where the engines peak torque is to help you get over the next hill.

As counter-intuitive as it seems, reliability and complexity are unrelated. In spite of being quite complex, the Prius is perhaps the most trouble free vehicle on the road, and is over represented among vehicles still operating beyond 200,000 miles.

On the other hand, the main failure with the Tundra was the corrosion proofing of the steel in the frame, which is pretty inexcusable considering they had the same problem with the first generation. If the design is good, the parts are high quality and the assembly is correct, a vehicle will not have excessive failures.

On the other hand, the most stone ax simple machine will fail if any of those three areas are compromised. Which maybe explains why my old 1.6 liter Tercel burned less oil in 300,000 miles than my 302 equipped Explorer did in 100,000.

I personally think a 10spd is the perfect transmission assuming the spacing are evenly spaced out. What I would like to see is a 10spd transmission that has the ability to run 5spd in normal and 10spd in tow/haul mode. A tow/haul mode that when not selected, the transmission shifts and uses only 2,4,6,8,10 and when you do tow or haul heavy loads, select tow/haul mode and the transmission will go through 1-10 for more efficient towing or hauling. A light or empty truck don't really need to start off with a super low 1st gear and go through all those closely spaced gears. 2,4,6,8,10 is plenty to move a empty truck along just fine.

Probably pointless to go beyond 10, 6 is probably fine for most people, unless hauling/towing heavy all the time.

Big rigs also have double-digit transmission gears because the rev range of the engine is so limited. When your engine redlines at just 2100, you need all those gears to reach any speed above a crawl, considering the load they're usually hauling. When you put a 10-speed with a high-rev turbo gasoline engine, the benefit is greatly reduced because the engine will likely never reach its power peak (these days, usually in the 5000 rpm neighborhood). Or, as G.R. writes, if you use the rev range of the engine, the 8/9/10-speed won't upshift when you feel you need it.

I have four speed automatic in 08 Silvy and get 26 mpg,,plenty good for my needs

I wouldnt mind having more gears only IF there was a way to hold it in any gear one wants

The More gears the better just so long as it doesn't compromise the longevity of the transmission(from heat due to constant shifting or lighter gears) and the transmission is a practical size for a pickup. More gears means closer spacing between gears so smoother shifting which contributes to being easier on the rest of the drive train and also staying in the peak torque range in the rpms

Also, doesnt most modern automatics start our in 2nd or 3rd unless you floor it? I know the 545rfe and 66rfe does. And I think the zf 8 speed ram 1500 uses will lockout some gears In tow/haul for longer spacing between gears to reduce constant shifting to prevent overheating.

I wouldnt mind having more gears only IF there was a way to hold it in any gear one wants

Posted by: Chevrolet builds a better way to see the USA | Dec 20, 2016 5:22:23 PM

GM's 6L80 and Ford's 6R80 lets you do that. It'll force a downshift when you drop below 1000 rpm or so but holds any gear you select otherwise. I'm sure any transmissions they develop together has that ability.

When will they learn and install 2 speed differentials in a pickup?

"Interestingly, Ford's jump from a six-speed (2016) to 10-speed (2017) earned the F-150 all of a 1 mpg EPA-estimated fuel-economy increase for combined and city driving."

This is pathetic. All that expensive R&D with GM, and all they come up with is a measly 1-mpg increase? Please. Will that massive economic benefit be negated by paying for additional repairs on the 10-speed?

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"How many gears do you think are necessary to make your pickup work the way you need it to?"

Five (5). Start with "three on the tree", and add one below for easy start-up and towing; and then add one up above (beyond the 1:1 ratio) for highway cruising and fuel mileage. Done.
(Six (6) would be OK too, but anything beyond that is marketing one-upsmanship baloney, IMO.) Keep it simple!

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"And where do we reach diminishing returns against added cost or lost longevity, serviceability, mileage and torque management?"

Any pickup with seven (7) gears or beyond has already reached that point, IMO. Would like to see what's left of that 10-speed after 15 years, 150,000 miles, and frequent uphill towing of 8,000 lbs or more in the summer heat.

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"How many gears are too many?"

Seven (7) or more.

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"Does anyone still need to shift through the gears anyway?"

Since all five of my vehicles have manual transmissions, it would be difficult to operate them properly with shifting through the gears (^_^).

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CORRECTION - - -

"..it would be difficult to operate them properly with shifting through the gears (^_^)."

Should be...

"it would be difficult to operate them properly WITHOUT shifting through the gears (^_^)."

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In a ram with the zf 8 speed, the first 4 gears are for 0-108 mph. 7 is overdrive city, 8 is overdrive highway. But what is 5 and 6 you ask? These are the added gears that aren't really needed imo. 5 and 6 are light throttle downshifts say when you hit a hill, unloaded. Instead of going from 1600 rpm to 3000 rpm you may only go up to 2000 rpm. In other words, more gears allow more engine rpm control, which allows the ecu to better manipulate the engine.

Here in sc I rarely hit hills so I rarely hit 5th and 6th gear. I don't think it even goes through 5th and 6th in upshifting. I'll pay attention next time I drive.

There is more to a transmission than just gears. Example, torque converter lockup, transmission fluid temperature, torque capacity, case material, manufacturer, country of origin, rear axle ratio, etc. A lot of things to consider when picking a transmission. If chrysler would have put the 66rfe in the 1500 instead of turning the 545rfe into the 65rfe I would prefer the 66rfe over the 8hp70 because it is chrysler and it is American and it can handle a lot torque. I had a 2013 65rfe and I hated the gaps between gears which were noticeable even with a regular cab short bed 2wd hemi 3.92 anti spin diff.

according to motortrend fuel economy increased from 16.8 combined to 18.7 combined with a significant power increase too. their fuel economy ratings are based on real world driving. 18.7 is pretty dang good. in the city it jumped from 14.8 to 17.1. that is an excellent improvement.

Adding cogs to the tranny is an easy and cheap way to address CAFE concerns. As usual the feds are trying to make the rest of us, the taxpayers, do something that they refuse to do themselves.

Obama pushed hard for tougher CAFE numbers, but he and his pals in Washington ride around in huge bulletproof cars and SUVs. His vacations have become famous for costing millions of dollars each, and he takes a LOT of them.

The CAFE standards need to be scrapped. Allow car makers and their customers to decide whether they want FE or not.

More gears means average Joes are going to see better average combined fuel economy numbers with improved driveability.

My 6spd F150 is programmed pretty well to lug high gears around town, but that means that sometimes when I need it to move a little quicker I have to really get on the gas to get it to kick down or manually move the select to the lower gear. With more gears and smaller gaps between gears the transmission has more flexibility to balance desired power/acceleration with maximizing efficiency at a given engine speed.

I imagine the transmission will also spend less time hunting when pulling trailers. It can find the right gear and just settle in whereas with the old 4 speed trucks you were constantly going between lugging in OD and then kicking down to 4k RPMs in 3rd and then back to OD every time you hit the slightest incline.

The only problem I have with the 8-9-10 gears transmissions is where the direct gear (1:1) is. Most of the time it's on the 5th or 6th gear. That leaves you with 2 or 3 gears of overdrive. On the Jeep Cheerokee, the 9th gear barely ever comes on... The 1:1 gear is the best to tow. So if it's on the 5th gear, what are the other 3-4 gears for then ? assuming you don't tow on overdrive...

"Interestingly, Ford's jump from a six-speed (2016) to 10-speed (2017) earned the F-150 all of a 1 mpg EPA-estimated fuel-economy increase for combined and city driving."

That may not seem like a lot, but scale those numbers and it starts to become clear why ANY measurable increase in efficiency is important:

Assume 18mpg vs 19mpg, 15k miles per year and 500K trucks per year. On average, one barrel of oil yields 19 gals of gasoline and 1 gal of gasoline produces 20lbs of CO2. Do the math and you realize that IF that 1mpg increase is real, that equates to a year over year difference of:

21,929,825 fewer gallons of gas

1,154,201 fewer barrels of oil

219,298 fewer tons of CO2

For reference, the US consumes about 19 million barrels of oil per day. This level of improvement certainly won't break our dependency on oil, but if you apply that same sort of analysis across every vehicle sold, you begin to see that even small, incremental increases in fuel economy can have a very large impact on both the amount of fuel we consume and emissions we produce as a nation.

A Ford engineer told The Fast Lane Truck that they did lots of research and testing, and found that 10 speeds is the maximum before you cross into the point of diminishing returns. So, don't look for the number of gears to keep climbing.

I personally don't think 10 speeds will achieve better mileage than 6 speeds in the real world.

C'mon we won't be happy until we get a 20 and 30 speed transmission.

The Ford-GM 10 speed automatic doesn't have much ratio spread, for how many gears it has.
1st-8th has less spread than 1st-6th of the GM 6 speed automatics & the ZF 6 speed automatic that Ford uses.
1st-9th has less spread than 1st-8th of GM's own 8 speed auto.
2nd-9th has less than the OLD GM 4 speed automatic.

The 2nd generation ZF 8 speed automatic, has more ratio spread than 1st-10th; and Chrysler should be using that in the 2018 Ram 1500.

This level of improvement certainly won't break our dependency on oil, but if you apply that same sort of analysis across every vehicle sold, you begin to see that even small, incremental increases in fuel economy can have a very large impact on both the amount of fuel we consume and emissions we produce as a nation.

@Chris

You need to get out more often! You're reciting the platitudes of the 1970s without apparently realizing that oil and coal are abundant and advances in emissions technology has plateaued.

The huge price of achieving incremental gains does not come without cost. People are forced to pay that cost.

Why do they need more Gears for MPG to gain 1 Mile is a joke . Just more cost and weight in the Trans !! In the Bigger Diesels it makes sense with 1500 Ft Lbs of TQ you can roll along at 1000 RPMS at 62 MPH. A Real Allison Guy would tell you 6 is all you need in most applications.

QUIT PISSING WITH GEARS

CVT Type Of transmission would be much more efficient

5 or 6 gears is enough in a pickup, more than that seems overkill. Now in a big truck, 10 kinda sucks, I have 18 speeds in mine and it works good.

7 sp 8 sp 10 sp doesn't matter
the ratios are what counts
1 ovr drive at .63 :1 is much better than 3 over drive rations with the top one at .75:1

There is so much more to it than just how many gear ratios - you have to consider the gear spread, percent changes gear-to-gear, final-drive selection, torque converter behavior and in-gear response, shift behavior along with engine torque profile - many of these have improved vastly with successive transmission designs (along with adding gears) due to better engineering and materials science, and improved computer control.

The 10R/10L90 seems to be a pretty great compromise on all fronts and a worthy followup to the 6R (ZF 6HP) and 6LXX/8LXX designs, especially when considering that the engine and final drive pairings are not being changed. Looking to the future, the tight-ratio 10-speed will be a good match to downspeeding that is almost certain to occur (and already occuring) in both gas and diesel engines.



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