Downshifting Or Braking Downhill -- Which Is Better

[RandyBlackburn]

I've got a '93 GS300 with only about 80K miles. When I bought the car a few years ago, I was told that the brakes might need replacing in a while.

Well, they still work fine, but partly because I downshift when going down steep hills rather than brake. Some people have told me that this is hard on the tranny (which is working fine so far), and the tranny is a lot more expensive to repair.

I've kept downshifting so far because I live at the top of a long fairly steep hill, and the owner's manual discusses downshifting. I downshift to 2nd to maintain a speed of about 50-55, and it doesn't over-rev.

I look forward to your comments, especialy those based on actual experience/knowledge

Thanks,

Randy

[yung1s]

I've been told the SAME thing and I completely agree with downshifting and disagree with braking...

1) your manual suggests it and

2) that's what your tranny is made for. You gotta figure when you pound on that gas pedal, you're putting a lot of stress on your tranny anyways, what difference is there going the opposite way? Your engine only revs so much and your tranny was built to handle your engine speeds. Now that's not to say you want to slam it into 2nd gear at freeway speeds - just be smart about it and it'll be fine. I was taught that you slow down using your tranny and I've been doing it for years and I've never had ANY problems with my trannies on any of my cars.

Just my 2 cents...

[SRK]

When you manually select a gear with the lever the trans uses the "sprag" to drive the engine - torque flows towards the engine rather than the normal direction which is towards the diff. The sprag is an over-running clutch, and to downshift and engage it is certainly a different path. The engine is then driven to a higher RPM with less cylinder pressure because of the closed throttle. That produces mild braking effect. That may be useful under some conditions, but the brakes on the car are designed with one thing in mind, and that's to slow the vehicle. So using the brakes is the best idea. A set of brake pads is cheap, the rotors last forever, and the trans is left to it's own devices courtesy of it's ECM programming.

You're not driving a semi-tractor with Jake Brakes. It's a car with very powerful wheel brakes. My advice is to use them, not the engine and trans.

[CarbonGS]

When you manually select a gear with the lever the trans uses the "sprag" to drive the engine - torque flows towards the engine rather than the normal direction which is towards the diff. The sprag is an over-running clutch, and to downshift and engage it is certainly a different path. The engine is then driven to a higher RPM with less cylinder pressure because of the closed throttle. That produces mild braking effect. That may be useful under some conditions, but the brakes on the car are designed with one thing in mind, and that's to slow the vehicle. So using the brakes is the best idea. A set of brake pads is cheap, the rotors last forever, and the trans is left to it's own devices courtesy of it's ECM programming.

You're not driving a semi-tractor with Jake Brakes. It's a car with very powerful wheel brakes. My advice is to use them, not the engine and trans.

i couldn't have said it better myself. the brakes on our cars were designed to stop them. although it sounds cooler to downshift, it isn't meant to stop the car on our platform. if you did a manual conversion however you'd have to downshift! i.e. different transmission!