makes you wonder if they do much actual over the road testing before manufacture/sale
GM's new 9 speed 9T50
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Originally Posted By: B320i
9 speeds is too many speeds.
After 100K of going up and down through all those gears, it will be completely knackered and the lower gears in particular will get quite rough. With this many gears, you'd be better with a CVT.
What I would LIKE to see in transmissions for normal automotive applications is programming that detects hills and automatically kicks down (like Voith and ZF transmissions on buses do). The other aspect of this feature is hill descents, where autos have a nasty tendency of racing ahead - the hill sensing would then hold a lower gear, with locked torque converter for engine braking.
On that note, a hydraulic retarder device would be nice, too!
In most autos, I manually go through the gears anyway, particularly in situations where varying acceleration can cause too much up & down shifting. I also prefer to use engine brake over standing on the brakes in an auto. I've noticed on some vehicles that the torque-converter locks up in the lower gears in manual mode, whereas it won't when left in "D."
My other gripe is my overtaking technique; in a manual such as my E36, I drop (a) gear and floor it - but keep 3-4K RPM. In an auto, the trans will assume you want to rev out to line - making such a maneuver very awkward, particularly as you wait for the transmission to figure out how many gears to (roughly) shift through...
I ride my bike in the hills near my house quite a bit, and I usually hear Voith-equipped buses kickdown to 2nd or 3rd gear and the whine of the retarder for quite a while. Allisons now do this, the newest ones will restrict themselves to 4th gear on inclines.
Toyota and Mercedes did implement some kind of "grade logic" - the W126 S-Class and the Lexus LS400 used a barometric sensor to sense if the car's climbing or descending a hill and it will attempt to shift accordingly. I still shift manually for hills, some cars like Subarus can't tell if you're going up a hill.
9 speeds is too many speeds.
After 100K of going up and down through all those gears, it will be completely knackered and the lower gears in particular will get quite rough. With this many gears, you'd be better with a CVT.
What I would LIKE to see in transmissions for normal automotive applications is programming that detects hills and automatically kicks down (like Voith and ZF transmissions on buses do). The other aspect of this feature is hill descents, where autos have a nasty tendency of racing ahead - the hill sensing would then hold a lower gear, with locked torque converter for engine braking.
On that note, a hydraulic retarder device would be nice, too!
In most autos, I manually go through the gears anyway, particularly in situations where varying acceleration can cause too much up & down shifting. I also prefer to use engine brake over standing on the brakes in an auto. I've noticed on some vehicles that the torque-converter locks up in the lower gears in manual mode, whereas it won't when left in "D."
My other gripe is my overtaking technique; in a manual such as my E36, I drop (a) gear and floor it - but keep 3-4K RPM. In an auto, the trans will assume you want to rev out to line - making such a maneuver very awkward, particularly as you wait for the transmission to figure out how many gears to (roughly) shift through...
I ride my bike in the hills near my house quite a bit, and I usually hear Voith-equipped buses kickdown to 2nd or 3rd gear and the whine of the retarder for quite a while. Allisons now do this, the newest ones will restrict themselves to 4th gear on inclines.
Toyota and Mercedes did implement some kind of "grade logic" - the W126 S-Class and the Lexus LS400 used a barometric sensor to sense if the car's climbing or descending a hill and it will attempt to shift accordingly. I still shift manually for hills, some cars like Subarus can't tell if you're going up a hill.
Originally Posted By: edwardh1
makes you wonder if they do much actual over the road testing before manufacture/sale
Yeah they do, a lot actually. Problem is that you can do so much testing in certain period of time. They have time limit, and while they do a lot of miles, that does not resemble long period of time use in city etc.
makes you wonder if they do much actual over the road testing before manufacture/sale
Yeah they do, a lot actually. Problem is that you can do so much testing in certain period of time. They have time limit, and while they do a lot of miles, that does not resemble long period of time use in city etc.
Originally Posted By: edyvw
They keep price. But, that is ZF fluid. Now, you can use fluids that also meet ZF requirements, and for example Valvoline Maxlife Full Synthetic meets it, Castrols, Mobil1, Redline etc. I decided to use ZF6 since I am not going to do flush, of course. So do not want to mix fluids.
As for change interval, this is tricky. Each car manufacturer has its own recommendation. BMW claims it is life fluid. If to be changed, they recommend on 100K. ZF on other hand recommends change between 60K and 75K. I am going with ZF in this case!
I'd stick with the ZF fluid. While those companies might claim to meet the fluid spec I wonder what would happen in the event of a problem. I wouldn't want to find out, nor would I trust the mfg of the fluid to back me up. I'd pony up for the ZF fluid, in time the price will come down.
Now if my vehicle was out of warranty and I read some good reviews of alternate ATF's that other people have tried I might take a shot.
They keep price. But, that is ZF fluid. Now, you can use fluids that also meet ZF requirements, and for example Valvoline Maxlife Full Synthetic meets it, Castrols, Mobil1, Redline etc. I decided to use ZF6 since I am not going to do flush, of course. So do not want to mix fluids.
As for change interval, this is tricky. Each car manufacturer has its own recommendation. BMW claims it is life fluid. If to be changed, they recommend on 100K. ZF on other hand recommends change between 60K and 75K. I am going with ZF in this case!
I'd stick with the ZF fluid. While those companies might claim to meet the fluid spec I wonder what would happen in the event of a problem. I wouldn't want to find out, nor would I trust the mfg of the fluid to back me up. I'd pony up for the ZF fluid, in time the price will come down.
Now if my vehicle was out of warranty and I read some good reviews of alternate ATF's that other people have tried I might take a shot.
Originally Posted By: demarpaint
Originally Posted By: edyvw
They keep price. But, that is ZF fluid. Now, you can use fluids that also meet ZF requirements, and for example Valvoline Maxlife Full Synthetic meets it, Castrols, Mobil1, Redline etc. I decided to use ZF6 since I am not going to do flush, of course. So do not want to mix fluids.
As for change interval, this is tricky. Each car manufacturer has its own recommendation. BMW claims it is life fluid. If to be changed, they recommend on 100K. ZF on other hand recommends change between 60K and 75K. I am going with ZF in this case!
I'd stick with the ZF fluid. While those companies might claim to meet the fluid spec I wonder what would happen in the event of a problem. I wouldn't want to find out, nor would I trust the mfg of the fluid to back me up. I'd pony up for the ZF fluid, in time the price will come down.
Now if my vehicle was out of warranty and I read some good reviews of alternate ATF's that other people have tried I might take a shot.
Nah, even if it was out of warranty I would stick to ZF. It is not like one would do fluid changes every 5K.
Originally Posted By: edyvw
They keep price. But, that is ZF fluid. Now, you can use fluids that also meet ZF requirements, and for example Valvoline Maxlife Full Synthetic meets it, Castrols, Mobil1, Redline etc. I decided to use ZF6 since I am not going to do flush, of course. So do not want to mix fluids.
As for change interval, this is tricky. Each car manufacturer has its own recommendation. BMW claims it is life fluid. If to be changed, they recommend on 100K. ZF on other hand recommends change between 60K and 75K. I am going with ZF in this case!
I'd stick with the ZF fluid. While those companies might claim to meet the fluid spec I wonder what would happen in the event of a problem. I wouldn't want to find out, nor would I trust the mfg of the fluid to back me up. I'd pony up for the ZF fluid, in time the price will come down.
Now if my vehicle was out of warranty and I read some good reviews of alternate ATF's that other people have tried I might take a shot.
Nah, even if it was out of warranty I would stick to ZF. It is not like one would do fluid changes every 5K.
Originally Posted By: edyvw
Originally Posted By: demarpaint
Originally Posted By: edyvw
They keep price. But, that is ZF fluid. Now, you can use fluids that also meet ZF requirements, and for example Valvoline Maxlife Full Synthetic meets it, Castrols, Mobil1, Redline etc. I decided to use ZF6 since I am not going to do flush, of course. So do not want to mix fluids.
As for change interval, this is tricky. Each car manufacturer has its own recommendation. BMW claims it is life fluid. If to be changed, they recommend on 100K. ZF on other hand recommends change between 60K and 75K. I am going with ZF in this case!
I'd stick with the ZF fluid. While those companies might claim to meet the fluid spec I wonder what would happen in the event of a problem. I wouldn't want to find out, nor would I trust the mfg of the fluid to back me up. I'd pony up for the ZF fluid, in time the price will come down.
Now if my vehicle was out of warranty and I read some good reviews of alternate ATF's that other people have tried I might take a shot.
Nah, even if it was out of warranty I would stick to ZF. It is not like one would do fluid changes every 5K.
That's why I used the word might. I took a shot at Maxlife in a 00 Century, but there was years of people with positive results, and a good friend/mechanic used it with great results. I was pleased. But an 8 or 9 speed ZF transmission is big money to replace. I'd probably use the ZF fluid too.
Originally Posted By: demarpaint
Originally Posted By: edyvw
They keep price. But, that is ZF fluid. Now, you can use fluids that also meet ZF requirements, and for example Valvoline Maxlife Full Synthetic meets it, Castrols, Mobil1, Redline etc. I decided to use ZF6 since I am not going to do flush, of course. So do not want to mix fluids.
As for change interval, this is tricky. Each car manufacturer has its own recommendation. BMW claims it is life fluid. If to be changed, they recommend on 100K. ZF on other hand recommends change between 60K and 75K. I am going with ZF in this case!
I'd stick with the ZF fluid. While those companies might claim to meet the fluid spec I wonder what would happen in the event of a problem. I wouldn't want to find out, nor would I trust the mfg of the fluid to back me up. I'd pony up for the ZF fluid, in time the price will come down.
Now if my vehicle was out of warranty and I read some good reviews of alternate ATF's that other people have tried I might take a shot.
Nah, even if it was out of warranty I would stick to ZF. It is not like one would do fluid changes every 5K.
That's why I used the word might. I took a shot at Maxlife in a 00 Century, but there was years of people with positive results, and a good friend/mechanic used it with great results. I was pleased. But an 8 or 9 speed ZF transmission is big money to replace. I'd probably use the ZF fluid too.
Since the ZF 8HP/9HP found it's way to rental fleets by way of Chrysler, I wouldn't be surprised if Lubrizol or Afton rented out a fleet to test out a new add pack which might make its way to a AMAM ATF like MaxLife. The problem is that they might spread things out too thin - MaxLife already meets DexVI/Mercon LV specs, and Toyota/Nissan/Honda specs(JASO 1A) but unofficially.
The Germans have Shell or XOM formulate their fluids and who knows what they spec for kinematics or frictional specs or even the add pack maker - it might be Lubrizol, it might be BASF, or even Shell. I think Lubrizol said they already meet Mercedes's ATF spec for their recent but not brand-new trannies.
/edit, it was Afton who met the 7-speed Mercedes specs. http://www.aftonchemical.com/SBU/DrivelineAdditives/AutomaticTransmission/HiTEC-4031
The Germans have Shell or XOM formulate their fluids and who knows what they spec for kinematics or frictional specs or even the add pack maker - it might be Lubrizol, it might be BASF, or even Shell. I think Lubrizol said they already meet Mercedes's ATF spec for their recent but not brand-new trannies.
/edit, it was Afton who met the 7-speed Mercedes specs. http://www.aftonchemical.com/SBU/DrivelineAdditives/AutomaticTransmission/HiTEC-4031
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