Auto transmission revs- normal?

[sunking247]

Hi, I live in Colorado and typically drive my 1999 Subaru Outback station wagon (2.4 engine, non-turbo, 4 cyl) up into the mountain passes. The issue is that it has an automatic transmission, and on the downhills, where if I were driving a stick I would leave it in neutral and ride the brake rather than gearing down (I think it's cheaper to change out brakepads than transmissions) I leave it in D (overdrive right?). When I'm gaining speed, on a steeper section, it has a tendency to gear down, causing the RPMs to leap from 2500 or 3000 rpms to 4500 rpms, it jolts the car considerably to the point that the first time it happened I thought something was wrong. It doesn't feel right. It's annoying that the car takes control like this and I worry that it's really hard on the tranny and fuel economy. I would shift it into neutral and ride the brakes, however then i worry about putting it back into drive as the road flattens out. Is that bad for an automatic transmission car? To shift it into and out of D to 3, or 3 to 2, or N to 2/3/D as the car is moving?

[Andyjo]

i just throw it in 3rd if it's that bad... no problem, that's why you don't have to push the button to shift from D<->3

[Bmm001]

As I understand it, starting in '99 Subaru upgraded the TCU and shift logic in their automatic trannies. Some sort of "grade logic" was added and yes, they will downshift going downhill. I wouldn't worry too much about it, but I can understand how it's irritating. The problem with putting the car in neutral and riding the brakes is not just an issue of brakes being cheaper to replace than engine parts. I understand your logic and would tend to agree, but think of it this way: if you overheat the brakes by riding them downhill and you have to stop suddenly, you won't be able to. Just my two cents.

 

Brian M.