[Dogs 2C]

Bought a new 2017 RTL-E 6 speed (early VIN 9XXX) in Aug 2016, 42K trouble free miles (including quite a bit of towing). I traded it in for a 2022 RTL-E in 9 speed Dec 2021 (also quite a bit of towing). This fits into "life/vehicles could be perfect, but unfortunately isn't" conondrum...

• 6 speed wins: super easy ATF level checks & fills, easy going, and always unobtrusive & capable shifting
• 6 speed loses: higher than average failure rate (didn't affect me though)

• 9 speed wins: paddle shifting, more gears, better reliability
• 9 speed loses: abysmal maintenance provisions (no dip stick, expensive dealer-only ATF change), weird 8-7 and 5-4 dog-clutch downshifts (speeds up before slowing down)

Verdict: the 9 speed wins, but really, come-on ZF/Honda ... how hard would it be to put a dipstick on the 9 speed, and make user ATF changes possible (then we could overlook the weird dog-clutch stuff)

 

[GreginJaxFL]

The paddle shifter are great but using the engine for braking is pitiful.

i still love my 9 speed for it’s smoothness.

 

[Salish Seagull]

Bought a new 2017 RTL-E 6 speed...
...

• 9 speed loses: abysmal maintenance provisions (no dip stick, expensive dealer-only ATF change), weird 8-7 and 5-4 dog-clutch downshifts (speeds up before slowing down)

Verdict: the 9 speed wins, but really, come-on ZF/Honda ... how hard would it be to put a dipstick on the 9 speed, and make user ATF changes possible (then we could overlook the weird dog-clutch stuff)

I read somewhere (can't find it now, of course) that the reason the ZF-9 has no dipstick and is a pain to fill is because the factory fill was supposed to last the lifetime of the vehicle. Unfortunately, ZF defines "lifetime" as 100,000 miles. While this may be true of German vehicles, Hondas are just getting broken in at this point, so Honda had to schedule a fluid change at roughly every 60K miles.

 

[Apex]

Your SotP dyno needs recalibrating.

According to Car and Driver instrumented testing:

2017
0-60 = 6.6 seconds
1/4-mile = 15.2 seconds @ 93 MPH

2021
0-60 = 6.2 seconds
1/4-mile = 15.0 seconds @ 93 MPH

A 2020-2023 Ridgeline with the 9-speed launches much harder than the 2017-2019 with the 6-speed. A 6-speed Ridgeline will never catch up with a 9-speed Ridgeline.

Well since its subjective, maybe not. At max effort, I 100% agree. 9sp from a full lunch in 1st is actually somewhat impressive. However, for partially aggressive acceleration, roll on to 75% throttle, the 6sp 1st gear seems slightly better. What I am saying is if you are not using 1st in the 9spd, it is very comparable to the 6at.

However overall, I am really liking the ZF9. For regular driving its super smooth and always seems to have the right gear. For aggressive driving it has the deep 1st gear. But even coming off the line in 2nd, there is plenty of power. My only real complaint is the response of the paddles. However slow paddles are still better than no paddles.

Reliability aside, I say the ZF9 is a modest overall improvement compared to the 6AT. Factor in reliability and its not so close.

 

[HistorianX]

9 speed wins: paddle shifting, more gears, better reliability
9 speed loses: abysmal maintenance provisions (no dip stick, expensive dealer-only ATF change), weird 8-7 and 5-4 dog-clutch downshifts (speeds up before slowing down)

You forgot full manual control over every gear, which is great for towing, and that the first gear in the 9 speed is taller that first in the 6. And those "weird" dog clutches have a purpose: to match engine speed with road speed for downshifting, much like track drivers use heel-toe shifting with manual trannys for the same results.

 

[14v6]

9 speed is more like a 7 speed for me because 1 and 9 don't get used much.

Lets say you are on a small incline stopped at a red light and you want to make a left turn. When green, you have to give it some more gas than usual to get moving you make your turn and then let off the gas to finish the turn and it shifts to 3rd. When it's pointing straight, you give it gas again to accelerate and there's a noticeable dead spot there where it can't pull that gear. With a 9 speed with all those ratios to choose from that should never happen. My Accord with the 6 speed did the same thing but it had the power to pull the gear.

With downshifting when descending hills, don't bother downshifting from 5-4 because it will accelerate and you will have to use the brakes anyway. If it's a steep hill I'll hit the brakes, deal with the 5-4 and grab 3 and then it really takes hold and you can hear the engine scream it's beautiful melody. All of this amounts to something ineffective akin to the 6 speed with using d4 and L. If you live on the flats, 9 speed works well and it shifts consistently the same regardless of throttle. I found the 6 speed could be mushy upshifting at light throttle but with some more input, it shifted well.

There's a really hilly section of back roads when I drop off my daughter at college and I've experimented. Using S and having full control with the paddles works but it's far from smooth. At best, I use S and just use the brakes. This is where CVT's shine and with a hybrid you don't have to worry about saving brakes on steep hills just hit them and watch your battery fill up with zero brake pad wear.

The 6 speed had compromises, the 9 speed has compromises the 10 speed I hope doesn't.

When the time comes I'm gong to do a spill and fill on the 9 speed. Just buy the fluid and those expensive drain plugs and add 3.5 qts.

 

[lbjgh]

Your SotP dyno needs recalibrating.

According to Car and Driver instrumented testing:

2017
0-60 = 6.6 seconds
1/4-mile = 15.2 seconds @ 93 MPH

2021
0-60 = 6.2 seconds
1/4-mile = 15.0 seconds @ 93 MPH

A 2020-2023 Ridgeline with the 9-speed launches much harder than the 2017-2019 with the 6-speed. A 6-speed Ridgeline will never catch up with a 9-speed Ridgeline.

Haha, now with 700kms i haven't really beaten 'er. I guess I'm getting use to the 2 gear launches.

 

[Dogs 2C]

I read somewhere (can't find it now, of course) that the reason the ZF-9 has no dipstick and is a pain to fill is because the factory fill was supposed to last the lifetime of the vehicle. ...

Yes, I've read that too. Someone (@zroger73 ?) said that Stellantis models using the 8 speed ZF variant stated it was a "lifetime" sealed unit. We all know that critical fluids like oil, ATF, etc. need to be changed out. For cars / trucks / tractors, I'll never buy any "lifetime" sealed AT vehicles. I don't agree with the concept of "throw away" (non- serviceable key parts or fluids) vehicles. It's bad enough with "throw away" appliances and electronics. Yes I know that "throw away" means recycled, but it's still far less environmental impact (and $ cost to us) to service or repair what you have, than to replace it.

... And those "weird" dog clutches have a purpose: to match engine speed with road speed for downshifting, much like track drivers use heel-toe shifting with manual trannys for the same results.

Agreed. I've read that dog clutches are used by ZF to package all 9 gears into a small package. It's a clever design. The point I was trying to make is that all other ZF paddle downshifts (except 8>7 and 5>4) don't require them. I believe traditional planetary AT's (like Honda's 10 speed) can do all their manual paddle downshifts without dog clutches.

.... With downshifting when descending hills, don't bother downshifting from 5>4 because it will accelerate and you will have to use the brakes anyway. If it's a steep hill I'll hit the brakes, deal with the 5>4 and grab 3 and then it really takes hold and you can hear the engine scream it's beautiful melody. ...

Here in the mid-west, we have a lot of towns nestled in river valleys. As you descend into town, speed limits often quickly goes from 50+ to 40 to 30 to 25. So like you I have to hit the brakes when doing the 5>4 downshift (to avoid hitting the car in front of me in heavy traffic, when the dog clutch does the rev-match speed-up thing), then 4-3 (perfect for 25 mph hills). The whole point is that this negates the purpose of manual downshifting on hills to avoid applying brakes. ZF users in mountains don't see this (with miles long grades), but here we need immediate downshifts, or forget engine braking

.... The 6 speed had compromises, the 9 speed has compromises the 10 speed I hope doesn't.

When the time comes I'm gong to do a spill and fill on the 9 speed. Just buy the fluid and those expensive drain plugs and add 3.5 qts.

Yep - don't know if my budget will allow another new vehicle when my 2022 grows old. But I'd certainly like to see how Honda's 10 speed will do. Seems like a traditional planetary AT (no dog clutches), that's also serviceable (and hopefully reliable) should be a winner.

 

[zroger73]

Yes, I've read that too. Someone (@zroger73 ?) said that Stellantis models using the 8 speed ZF variant stated it was a "lifetime" sealed unit.

From the owner's manual of a recent Jeep Cherokee that uses the ZF 9-speed:

Fluid And Filter Changes
Under normal operating conditions, the fluid installed at the factory will provide satisfactory lubrication for the life of the vehicle.

Routine fluid and filter changes are not required. However, change the fluid and filter if the fluid becomes contaminated (with water, etc.), or if the transmission is disassembled for any reason.

Agreed. I've read that dog clutches are used by ZF to package all 9 gears into a small package. It's a clever design. The point I was trying to make is that all other ZF paddle downshifts (except 8>7 and 5>4) don't require them. I believe traditional planetary AT's (like Honda's 10 speed) can do all their manual paddle downshifts without dog clutches.

Here in the mid-west, we have a lot of towns nestled in river valleys. As you descend into town, speed limits often quickly goes from 50+ to 40 to 30 to 25. So like you I have to hit the brakes when doing the 5>4 downshift (to avoid hitting the car in front of me in heavy traffic, when the dog clutch does the rev-match speed-up thing), then 4-3 (perfect for 25 mph hills). The whole point is that this negates the purpose of manual downshifting on hills to avoid applying brakes. ZF users in mountains don't see this (with miles long grades), but here we need immediate downshifts, or forget engine braking.

ZF had some tough decisions to make when deciding which gears would use dog clutches and which would use friction clutches. On the surface, it appears they chose to use dog clutches where they would interfere least for the greatest variety of driving conditions. As to why they use dog clutches in a 9-speed when Honda and others were able to avoid them even with 10-speed transaxles, it is my understanding that the use of a couple of dog clutches, which themselves are strong, allowed other components to be more robust. For example, the gears in the 10-speed may have a lower torque limit in order to get them to fit inside the same package as the 9-speed (I don't know this - I'm just speculating because it seems logical).

 

[14v6]

[/QUOTE]

Here in the mid-west, we have a lot of towns nestled in river valleys. As you descend into town, speed limits often quickly goes from 50+ to 40 to 30 to 25. So like you I have to hit the brakes when doing the 5>4 downshift (to avoid hitting the car in front of me in heavy traffic, when the dog clutch does the rev-match speed-up thing), then 4-3 (perfect for 25 mph hills). The whole point is that this negates the purpose of manual downshifting on hills to avoid applying brakes. ZF users in mountains don't see this (with miles long grades), but here we need immediate downshifts, or forget engine braking.

Thank you sir!! I've been trying to articulate this. With my Accord V6 these situations were an absolute blast, just pop it in S and compression braking was pretty good and just hammer the gas to go back to 55 mph, fun. Hybrid pretty fun doing this too.

 

[longboat]

From the owner's manual of a recent Jeep Cherokee that uses the ZF 9-speed:

Fluid And Filter Changes
Under normal operating conditions, the fluid installed at the factory will provide satisfactory lubrication for the life of the vehicle.

Routine fluid and filter changes are not required. However, change the fluid and filter if the fluid becomes contaminated (with water, etc.), or if the transmission is disassembled for any reason.



ZF had some tough decisions to make when deciding which gears would use dog clutches and which would use friction clutches. On the surface, it appears they chose to use dog clutches where they would interfere least for the greatest variety of driving conditions. As to why they use dog clutches in a 9-speed when Honda and others were able to avoid them even with 10-speed transaxles, it is my understanding that the use of a couple of dog clutches, which themselves are strong, allowed other components to be more robust. For example, the gears in the 10-speed may have a lower torque limit in order to get them to fit inside the same package as the 9-speed (I don't know this - I'm just speculating because it seems logical).

I would like to see the ZF9 and Honda's AT10 side by side. At one point, it was mentioned that the AT10 wouldn't fit with the V6 and the transfer case in the current platform, which is why we got the ZF9 instead. It's possible the AT10 is significantly larger, or just shaped differently.

I'm even more curious about the weight and torque load specs between the two.

 

[Dogs 2C]

From the owner's manual of a recent Jeep Cherokee that uses the ZF 9-speed:

Fluid And Filter Changes
Under normal operating conditions, the fluid installed at the factory will provide satisfactory lubrication for the life of the vehicle.

Routine fluid and filter changes are not required. However, change the fluid and filter if the fluid becomes contaminated (with water, etc.), or if the transmission is disassembled for any reason.
....

Thanks for clarifying it's the Jeep's ZF 9 speed flavor that has a "life of the vehicle" service interval (but still references non "routine" changing ATF & filter). So means Jeep's ZF9 flavor must still have ATF drain and fill plugs - I'm guessing in the same configuration as Honda's ZF9? So technically it's not a "sealed" AT.

In looking at Honda's ZF9 speed ATF replacement and level check procedure (on Service Express - it's complicated), it appears (to me at least) that ZF designed the transmission to normally do ATF fill & check usually by the factory (i.e. - on the assembly line). Then it appears ZF adapted the factory procedure to allow for drain/fill/check in the field. If you follow their procedure, then it's impossible for the average Honda ZF 9 speed owner to do the "official" ATF drain/fill/check procedure DIY (because it specifies a lift, and Honda HDS test system).

Edit: many forum posts and YouTube videos with "unofficial" (i.e. - non Honda specified) DIY drain & fill alternative procedures (disclaimer: proceed at your own risk), some sketchy, others seemingly well thought out. Me, to avoid any risk of AT damage & warranty denial (on my $43K vehicle), I'll probably wait until after my OEM warranty runs out to consider them.

 

[HistorianX]

The paddle shifter are great but using the engine for braking is pitiful. i still love my 9 speed for it’s smoothness.

I drive high passes in the Rocky Mountains a regular basis and find that the 9 speed does very well for manual engine braking--once you get over that eerie feeling of the 5>4 downshift and the momentary hesitation as the ZF matches engine to road speed.

 

[GreginJaxFL]

I drive high passes in the Rocky Mountains a regular basis and find that the 9 speed does very well for manual engine braking--once you get over that eerie feeling of the 5>4 downshift and the momentary hesitation as the ZF matches engine to road speed.

‘I have not got over that “eerie“ feeling. Living in Florida which is flatter than a pancake, I seldom need it. Love the mountains, I miss them, used to live on Beach Mountain.

 

[zroger73]

Lightly applying the brakes until the 5-4 downshift completes helped reduce the "eerie" feeling for me.

 

[wjfyfe]

Lightly applying the brakes until the 5-4 downshift completes helped reduce the "eerie" feeling.

No first gear braking with the 6-speed, braking while downshifting with the 9-speed, Honda do like ya to use them brakes, don't they?
Bill

 

[longboat]

No first gear braking with the 6-speed, braking while downshifting with the 9-speed, Honda do like ya to use them brakes, don't they?
Bill

I have yet to drive any Honda that has strong brakes, but I've never driven the S2000 or NSX.

The brakes in my '19 RTL are adequate, but I would not call them strong.

 

[Kevo]

The brakes in my '19 RTL are adequate, but I would not call them strong.

I've had a couple of situations now where I've had to stomp on the brakes to the point where the anti-lock kicks in. They performed as well as any other vehicle I've had. The limit in my mind on this truck and my previous two Tundras was the friction of the tires with the road surface.

 

[Salish Seagull]

From the owner's manual of a recent Jeep Cherokee that uses the ZF 9-speed:

.... For example, the gears in the 10-speed may have a lower torque limit in order to get them to fit inside the same package as the 9-speed (I don't know this - I'm just speculating because it seems logical).

According to PRL Motorsports, the 10AT starts to slip at about 420 ft/lb torque. PRL Blog.See 4th paragraph.

Due to the nature of the DynaPack's increased load capability during a power curve test, torque needed to be limited in the midrange, as some transmission slip was detected when more than 420ft/lbs was made at earlier engine speeds (possibly when available transmission line pressure is lower).

I'll see if I can find something on the ZF-9.

 

[zroger73]

I'll see if I can find something on the ZF-9.

The ZF 9HP is rated to handle 354 lb-ft.

The 6AT was introduced with a torque capacity of 295 ft-lbs.

The 10AT was introduced with a torque capacity of 275 ft-lbs "with some degree of headroom designed in". It is currently used in applications producing up to 354 lb-ft of torque after being upgraded for those applications (TLX Type S and MDX Type S).