| bb123 |
I am not, by any stretch, a mechanical engineer, but it occurs to me that Honda/Acura's transmission problems may be linked to their desire to gey the highest mileage possible from each drivetrain.
I say this because I have owned a number of Hondas, and all of them have had a very "smooth" drivetrain. By that, I mean that my Hondas have never had any engine braking to speak of. While my old GMs and newer Mercedes slow down when I lift off the throttle on a downhill, my auto tranny-Hondas have always seemed to speed up, with the drivetrain providing little resistance. In addition, my auto tranny-Hondas have always had some drivetrain lash (when I make a sharp turn with my foot on the brake and then accelerate, the drivetrain revs high and then "thumps" into gear).
I have noted several of those with new transmissions have complained of reduced gas mileage after the replacement. I wonder if Honda/Acura has strengthened transmission/torque converter to reduce failure, with more friction and lower mileage as a side effect? |
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| DaleB |
quote:
Originally posted by bb123
I am not, by any stretch, a mechanical engineer, but it occurs to me that Honda/Acura's transmission problems may be linked to their desire to gey the highest mileage possible from each drivetrain.
I say this because I have owned a number of Hondas, and all of them have had a very "smooth" drivetrain. By that, I mean that my Hondas have never had any engine braking to speak of. While my old GMs and newer Mercedes slow down when I lift off the throttle on a downhill, my auto tranny-Hondas have always seemed to speed up, with the drivetrain providing little resistance. In addition, my auto tranny-Hondas have always had some drivetrain lash (when I make a sharp turn with my foot on the brake and then accelerate, the drivetrain revs high and then "thumps" into gear).
I have noted several of those with new transmissions have complained of reduced gas mileage after the replacement. I wonder if Honda/Acura has strengthened transmission/torque converter to reduce failure, with more friction and lower mileage as a side effect?
There is no doubt the entire drivetrain has to be a consideration when trying to establsh the best MPG. I would think most the changes would be in gearing and shift timing, and while the torque converter plays some part in multiplying torque input, most of the problems associated with the transmission have appeared to be in the gear packs and not the converter, with the exception of the latest recall which appears to be a shaft journal overheating and causing gear teeth to fracture, on a very small population of cars.
The later vehicles, most notably the MDX, have 'grade-logic' to provide better engine braking on long descents. This is about the only real braking one can feel from the drivetrain.
I have not experienced very noticable 'backlash' under the conditions you specify. I am sure there is some, but it should be minimal and snubbed up quite a bit. With an all wheel drive system some slop would be expected over time. It seems it would be difficult to tell exactly where it's coming from unless it got so bad as to be noisy and repeatable with any sudden change in speed or shifting. Defective motor/transmission mounts can cause similar symptoms. |
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| bb123 |
mhassan's quote from another thread: http://www.acuramdx.org/forums/show...?threadid=18650
". . . .my MDX is now in the garage undergoing a transmission transplant. The fault I am told pertains to an issue with the torque convertor."
His MDX exhibited the usual 2-3 delayed gear change, "rumble strip" vibrations, etc.
I'm not giving up on my theory yet. |
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| DaleB |
quote:
Originally posted by bb123
I'm not giving up on my theory yet.
I stated "MOST of the problems associated with the transmission have APPEARED to be in the gear packs and not the converter".
That is based on what dealerships have told owners bringing in their MDX's for transmission problems. And you can find numerous reports of their experiences by doing more searches.
There were some indications in the Acura transmission design close to 2 years ago when TL's were being recalled, that the main problems were in the clutch packs.
That does not mean that torque converters never fail. |
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