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Excellent spreadsheet, thank you!

The dark window box is the area that I'm typically operating in, and my experience is that the transmission does not like to stay in 6th gear, and the 500-530 rpm difference between 5th and 6th hurts the gas mileage. Getting it to drop down into 6th is hard, and it will pop up into 5th if you breathe wrong.

Engine & tranny seem to really settle in a 65-66 mph = 2450 rpm / 5th gear, which holds firm even on a slight grade. Produces best 29+ MPG vs wind resistance vs grade conditions.
WOW, your van operates 2 gears LOWER than mine! Going 75 MPH on flat roads I was complaining that it prefers 7th gear (1971 RPM) over eighth gear (1633 RPM). But you are reporting 5th (2815 RPM) and 6th (2280 RPM) gears at that speed. That is really going to take a toll on your engine life turning those RPMs all the time.

Eighth gear is hard to find when going over 61 MPH, 61 and under it shifts into eighth gear with ease. All this may be due to the way the tranny "learned" my driving habits. YMMV
 

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WOW, your van operates 2 gears LOWER than mine! Going 75 MPH on flat roads I was complaining that it prefers 7th gear (1971 RPM) over eighth gear (1633 RPM). But you are reporting 5th (2815 RPM) and 6th (2280 RPM) gears at that speed. That is really going to take a toll on your engine life turning those RPMs all the time.

Eighth gear is hard to find when going over 61 MPH, 61 and under it shifts into eighth gear with ease. All this may be due to the way the tranny "learned" my driving habits. YMMV
I better go back, review my numbers, and report back :surprise:
 

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I find that I can maintain 8th gear 70mph on a flat road if I drive manually and ease off the gas slightly when going over the overpasses. Once I put the cruise control on the acceleration is too aggressive over the overpasses and the car kicks back down into 7th gear and it's almost impossible to get it back up into 8th gear unless you have a downhill grade to help you.

I don't understand why this car can't maintain 8th gear on it's own with the cruise control on if it's possible to do while driving manually on a flat road?
 

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What's the point of the 9th gear if it's never used? It seems to me that using that 9th gear at higher speeds (75+) would really help with fuel economy.
 

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I find that I can maintain 8th gear 70mph on a flat road if I drive manually and ease off the gas slightly when going over the overpasses. Once I put the cruise control on the acceleration is too aggressive over the overpasses and the car kicks back down into 7th gear and it's almost impossible to get it back up into 8th gear unless you have a downhill grade to help you.

I don't understand why this car can't maintain 8th gear on it's own with the cruise control on if it's possible to do while driving manually on a flat road?
I agree, over 61 MPH I get the same results as you, a long downhill is need to shift into 8th when traveling 62 MPH of higher. But, it will shift into 8th easily if your traveling less than 61 MPH, you don't even need to be going "downhill". So the roads with 55 MPH limit I'm in 8th gear but on expressways with 65 MPH speed limit I'm usually in 7th gear, doesn't make sense.

What makes 61 MPH the deciding factor when selecting a gear? Something is definitely wonky in their gear selection algorithm. :surprise:
 

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I agree, over 61 MPH I get the same results as you, a long downhill is need to shift into 8th when traveling 62 MPH of higher. But, it will shift into 8th easily if your traveling less than 61 MPH, you don't even need to be going "downhill". So the roads with 55 MPH limit I'm in 8th gear but on expressways with 65 MPH speed limit I'm usually in 7th gear, doesn't make sense.

What makes 61 MPH the deciding factor when selecting a gear? Something is definitely wonky in their gear selection algorithm. :surprise:
Thanks for confirming that for me. 0:) I was starting to think I was doing something wrong, since I read of a lot of these post about people using the cruise control at speeds over 60mph and everything is fine. I did another test run last week on a 50 mile straight flat stretch of road. The road is flat with the exception of a few overpasses. I started out from a dead stop and merged onto that highway slowly and watched as the Pac got into 8th gear around 55mph. I slowly eased onto the gas to get to 70mph and was able to drive for the next 30 miles without the cruise control on between 70-75mph in 8th gear. I decided to switch on the cruise control (Non ACC) at 70mph. It went ok for about a mile then an over pass came and it down shifted back into 7th gear cruising at 70mph. It would not go back up into 8th gear until I kicked off the cruise control just before another over pass and on the way down the over pass I was able to get it to shift back up into 8th gear and finished driving that route around 70-75mph.

It seems to me the shift logic on the 8th gear and higher seems messed up somehow.
 

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Correction to my previous #40 post, as I originally drew the RPM box in the wrong place.

Attached is Pappa60's spreadsheet, where I've added Black box showing the MPG sweet spot that Pappa60, Ed_Wong, and I have been discussing. The Black box shows sweet spot 8th gear RPM's at 70-75 mph. This is a very difficult spot to stay in with the cruise control engaged. Once van shifts into 7th gear shown by the Red box with the cruise engaged, it takes an act of Congress to get back into 8th.

Disengage the cruise, feather the throttle appropriately on slight upgrades, and you can stay in 8th. Too much effort in my book!

Do your own testing, and see for yourself.

I agree, over 61 MPH I get the same results as you, a long downhill is need to shift into 8th when traveling 62 MPH of higher. But, it will shift into 8th easily if your traveling less than 61 MPH, you don't even need to be going "downhill". So the roads with 55 MPH limit I'm in 8th gear but on expressways with 65 MPH speed limit I'm usually in 7th gear, doesn't make sense.

What makes 61 MPH the deciding factor when selecting a gear? Something is definitely wonky in their gear selection algorithm. :surprise:
I find that I can maintain 8th gear 70mph on a flat road if I drive manually and ease off the gas slightly when going over the overpasses. Once I put the cruise control on the acceleration is too aggressive over the overpasses and the car kicks back down into 7th gear and it's almost impossible to get it back up into 8th gear unless you have a downhill grade to help you.

I don't understand why this car can't maintain 8th gear on it's own with the cruise control on if it's possible to do while driving manually on a flat road?
I better go back, review my numbers, and report back :surprise:
WOW, your van operates 2 gears LOWER than mine! Going 75 MPH on flat roads I was complaining that it prefers 7th gear (1971 RPM) over eighth gear (1633 RPM). But you are reporting 5th (2815 RPM) and 6th (2280 RPM) gears at that speed. That is really going to take a toll on your engine life turning those RPMs all the time.

Eighth gear is hard to find when going over 61 MPH, 61 and under it shifts into eighth gear with ease. All this may be due to the way the tranny "learned" my driving habits. YMMV
 

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You know ZF was having a lot of problems when their 9 speed came out. I wonder if this not shifting to the highest gear is a response to the complaints. I mean, all they did was a software upgrade, not really anything mechanical. Maybe 9th gear isn't very strong and can't handle the torque?

On our Honda Ody, the 6 speed had all kinds of problems, with hard shifts and slipping. They updated the software and it fixed it mostly, but the mileage went down by a noticeable margin. It shifted later, higher in rpm, and didn't shift the the highest gear until you where on the highway at higher speed.
 

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What's the point of the 9th gear if it's never used?
So they can say it has a 9 speed transmission.

You know ZF was having a lot of problems when their 9 speed came out. I wonder if this not shifting to the highest gear is a response to the complaints.
It's not. I had the first version of this transmission in my Cherokee and I have never seen 9th gear. This is not new behavior.
 

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You know ZF was having a lot of problems when their 9 speed came out. I wonder if this not shifting to the highest gear is a response to the complaints. I mean, all they did was a software upgrade, not really anything mechanical. Maybe 9th gear isn't very strong and can't handle the torque?

On our Honda Ody, the 6 speed had all kinds of problems, with hard shifts and slipping. They updated the software and it fixed it mostly, but the mileage went down by a noticeable margin. It shifted later, higher in rpm, and didn't shift the the highest gear until you where on the highway at higher speed.
The last dog clutch does not want to shift from 7th to 8th gear over 61 MPH unless going downhill.

"To save space and increase efficiency, the 9HP uses two multi-plate clutch elements, two friction brakes and two electronically synchronized dog clutches. (The 8HP uses two brakes and three multi-plate clutches.) The way the gearsets are arranged inside the case, shifts from 1-2, 2-3, and 3-4 involve only the traditional friction brake and clutch elements. As you would expect, aside from 1st being fairly low and somewhat distant from 2nd, these shifts feel perfectly “normal.” Under hard acceleration there is a momentary reduction in engine torque (courtesy of the computer to reduce clutch wear) and the shift occurs quickly and smoothly. The shift from 4-5 however is different. The transmission has to disengage dog clutch “A” in addition to engaging a friction clutch. This shift takes slightly longer than the 3-4 shift and the car’s computer makes a drastic reduction in torque to prevent wear of the dog teeth. Shifts 5-6 and 6-7 again happen with the only the friction elements at which point we need to disconnect the final dog clutch for gears 8 and 9 so we get the same kind of torque reduction in those shifts. The result is a transmission that has two distinct “feels” to its shifts, one that has only a slight torque reduction (1-2, 2-3, 3-4, 5-6, 6-7, 8-9) and one that has a more “manual transmission” feel where torque is cut severely (4-5 and 7-8).
Because of the positioning of the two dog clutches in the shift pattern, the torque reduction isn’t objectionable in upshifts. Hard acceleration from a stop didn’t involve 5th gear even in the 1/4 mile. However, once you let off the gas the transmission will shift upwards rapidly for fuel economy settling in 6th or 7th in the 60-65 MPH range and 8th in the 70-75 MPH range." I don't agree with the last sentence since I reach 8th gear at 50MPH

Taken from this article: ZF's 9-Speed 9HP Transmission Puts Dog Clutches On The Leash
 

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Wish I had this chart on my recent trip from Pittsburgh to DC. 95% highway with the ACC set at 74 most of the time and I ended up with 25mpg. I kept an eye on the RPMs because I knew this chart existed, just didn't have a it handy. Don't think i ever saw it drop below 1500 RPM so I doubt I ever saw 9th. The trip isn't the flattest but I think it stayed in 7th and 8th most of time.
 

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Yes, as mentioned before in this thread, none of us so far have seen 9th gear. To have the transmission stay in 8th gear with the cruise control on you have to be on a flat road with no hills or overpasses. The cruise control likes to accelerate aggressively on any hill or grade which will cause the transmission to downshift to 7th gear and it usually won't upshift back into 8th gear unless you have a downhill portion to help it.
 

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9th gear does work on Pacificas :)

I was finally able to confirm the Pacifica does have a 9th gear that works. On a trip home from San Francisco last night on I-280 which has a lot longer up and downhill sections, I was able to get 9th gear to kick in multiple times.

I set the cruise control on level section of the road at 70 mph. engine rpm's were about 1600 rpm. On a uphill run, the transmission shifts to 6th gear, engine rpm's at 2200 rpm. On the way down the hill the transmission shifts back into 8th gear, engine rpm's at 1600 rpm's, then transmission shifts again into 9th gear, engine rpm's at 1300 rpm. Once the road levels out, it shifts back down to 8th gear, engine rpm's at 1600 rpm's. I was able to do this multiple times on the 50 mile trip.

So 9th gear does work on the Pacifica but, it's such a high of a gear, it's not likely you will be able to cruise in that gear for any extended distance.
 

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I was finally able to confirm the Pacifica does have a 9th gear that works. On a trip home from San Francisco last night on I-280 which has a lot longer up and downhill sections, I was able to get 9th gear to kick in multiple times.

I set the cruise control on level section of the road at 70 mph. engine rpm's were about 1600 rpm. On a uphill run, the transmission shifts to 6th gear, engine rpm's at 2200 rpm. On the way down the hill the transmission shifts back into 8th gear, engine rpm's at 1600 rpm's, then transmission shifts again into 9th gear, engine rpm's at 1300 rpm. Once the road levels out, it shifts back down to 8th gear, engine rpm's at 1600 rpm's. I was able to do this multiple times on the 50 mile trip.

So 9th gear does work on the Pacifica but, it's such a high of a gear, it's not likely you will be able to cruise in that gear for any extended distance.
Paddle shifter would be nice to lock 9 in as long as the computer doesn't sense lugging and autoshift to 8.
 

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We just need the engine to have an additional 200 foot pounds of torque at 1200 rpm and that should take car of any lugging issues :smile2:
 

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This tranny in different versions is used in vehicles from other manufacturers, in other parts of the world.
Other forums and articles state that 9th is there and often engages above 80mph in areas where speed limits are higher. On the Autobahn and New Jersey for example. Even then, if conditions dictate, it will drop into a lower gear very easily with winds or grades according to the write-ups.
Acura TLX, Chrysler 200, Chrysler Pacifica, Fiat Doblò, Fiat 500X, Honda CR-V (2015-), Honda Pilot, Jeep Cherokee (KL), Jeep Renegade, Ram ProMaster City, Range Rover Evoque, Land Rover Discovery Sport might have a variant of the 9-speed.
 

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Other forums and articles state that 9th is there and often engages above 80mph in areas where speed limits are higher. On the Autobahn and New Jersey for example.
Why would New Jersey be compared to the Autobahn? Isn’t the NJ speed limit still 65?
 

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I might be guilty of teasing how NJ drivers drive on their freeways...
Gotcha. Throw in a smiley or something next time so we know it’s a joke :smile2:
 
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