Originally Posted By: 440Magnum
I don't know, I would think that any advantage an engine picks up from a manual trans not loading it at idle would be more than offset by the impulsive loads during shifting and the constant banging of the throttle open and closed. Yes, a good driver can avoid most of that during shifting (I consider myself a pretty decent stick driver, my passengers don't bob their heads every shift anyway) but an automatic is still 10 times smoother. And the throttle just stays open and the engine sees a nice constant load. Of course the newest computer controlled automagic transmission controllers actually do throttle the engine back during shifts and wait until the sensors indicate that the RPMs are pre-matched before engaging the next gear, which is the smoothest method imaginable short of a CVT.
Another issue is the transmission system ITSELF. Manual transmissions rarely outright fail, although synchronizers tend to get iffy beyond 150k miles or so, but they always need clutches well before an automatic will need an overhaul. In my experience automatics always last well to the high side of 150k miles unless the automatic has some defect. A manual trans clutch replacement is a pretty big deal since the transmission (or engine, depending of the drivetrain layout) will have to be removed to replace the clutch. A neighbor just sold her Mazda 626 with only 124k miles on it because the clutch was gone, the front end was getting bad, and it was going to be a $700+ job for the clutch alone.
Odd, I've yet to need a clutch replacement, and I've had at least 3 high mileage cars, all with their factory clutches. I owned an 81 Rabbit diesel probably with 300K+ miles and the original clutch. (The odometer failed at 129K) Owned a Plymouth Horizon with over 100K miles and original clutch, and currently I have a '94 Geo Prizm with 235K miles and the original clutch.
So I don't buy that clutches fail before an automatic transmission. I've fixed or rebuilt more sub 100K automatics than I've replaced clutches (zero)
So my experience has been automatics are far more problematic than manuals, clutch included.
Originally Posted By: 440Magnum
All that plus the fact that the vehicles I've run out the absolute highest mileages (300k, 250k, and over 400k miles) have all been American v6 or v8 engines mated to automatics leads me to believe that automatic-transmission cars probably have the longevity edge.
Besides, there's something positively stone-age about rubbing a piece of un-lubricated friction material on a spinning metal plate to get a car moving... even though I wouldn't trade my stick Jeep for an automatic for anything.
I don't know, I would think that any advantage an engine picks up from a manual trans not loading it at idle would be more than offset by the impulsive loads during shifting and the constant banging of the throttle open and closed. Yes, a good driver can avoid most of that during shifting (I consider myself a pretty decent stick driver, my passengers don't bob their heads every shift anyway) but an automatic is still 10 times smoother. And the throttle just stays open and the engine sees a nice constant load. Of course the newest computer controlled automagic transmission controllers actually do throttle the engine back during shifts and wait until the sensors indicate that the RPMs are pre-matched before engaging the next gear, which is the smoothest method imaginable short of a CVT.
Another issue is the transmission system ITSELF. Manual transmissions rarely outright fail, although synchronizers tend to get iffy beyond 150k miles or so, but they always need clutches well before an automatic will need an overhaul. In my experience automatics always last well to the high side of 150k miles unless the automatic has some defect. A manual trans clutch replacement is a pretty big deal since the transmission (or engine, depending of the drivetrain layout) will have to be removed to replace the clutch. A neighbor just sold her Mazda 626 with only 124k miles on it because the clutch was gone, the front end was getting bad, and it was going to be a $700+ job for the clutch alone.
Odd, I've yet to need a clutch replacement, and I've had at least 3 high mileage cars, all with their factory clutches. I owned an 81 Rabbit diesel probably with 300K+ miles and the original clutch. (The odometer failed at 129K) Owned a Plymouth Horizon with over 100K miles and original clutch, and currently I have a '94 Geo Prizm with 235K miles and the original clutch.
So I don't buy that clutches fail before an automatic transmission. I've fixed or rebuilt more sub 100K automatics than I've replaced clutches (zero)
So my experience has been automatics are far more problematic than manuals, clutch included.
Originally Posted By: 440Magnum
All that plus the fact that the vehicles I've run out the absolute highest mileages (300k, 250k, and over 400k miles) have all been American v6 or v8 engines mated to automatics leads me to believe that automatic-transmission cars probably have the longevity edge.
Besides, there's something positively stone-age about rubbing a piece of un-lubricated friction material on a spinning metal plate to get a car moving... even though I wouldn't trade my stick Jeep for an automatic for anything.
