E320-40.7mpg commuting but rolling down hills

[ekm]

Hello all,

I only tried this twice... I commute 55 miles to work each day and typically hit 35-36 mpg on the trip computer with ac off. 15 minute city driving, 45 minutes highway driving. Highway speeds are 70-75mph with minimal traffic.

If I put the car in neutral and roll down the steeper hills, I can hit 40.7mpg. Both trail days hit the same mpg.

Does anyone know if the transmission will be damaged by this practice?

Thanks for any input....Ed

[Untertürkheim]

I would not do it, automatic transmissions are not made to engage or disengage at speed.

[TMAllison]

IIRC my 99's OM says don't coast in N; unless to a stop. We have the same trans.

[harkgar]

Originally Posted by TMAllison

IIRC my 99's OM says don't coast in N; unless to a stop. We have the same trans.

The fuel savings must be marginal. Two negative points.

When you are free-wheeling you can only steer but unable to accelerate out of a dangerous situation.

There is also the risk of transmission damage. The only car in the last 30 years or so with this feature is the Saab 96 manual transmission. There was this funny little level on the floor that can be pulled out - pushed in to engage or disengage this feature. Crappy car. I had one.