Q: I have a 2011 Subaru Outback with the 2.5-liter engine. I want to know if it is harmful to downshift often without using the brakes. Recently I hear a whining that has just started that I believe is coming from the transmission. I had the 60,000-mile service done, including replacing the transmission oil. I don't remember hearing the noise before the 60,000-mile service.
A: First, I assume you are describing downshifting a manual transmission, not an automatic. Many of today's manual gearboxes are smaller and utilize smaller internal bearings. This isn't a bad thing, of course, but I've heard from a number of transmission shop owners that they see more bearing issues from these transmissions now than in the past. They, and I, recommend using the brake to slow the vehicle rather than downshifting.
But why spoil the fun of driving a manual gearbox? Downshifting before a corner while still braking — the lost art of "heel and toe" and "double clutch" downshifting — isn't harmful and adds to the challenge of driving. Which increases situational awareness, reduces distraction and hopefully reduces "driver error" crashes.
The bottom line is this; brakes are far more efficient and far less expensive to replace than clutches and/or transmissions. While there's no real harm in downshifting to benefit from engine braking on occasion, such as a long downhill grade, you're better off using downshifts to prepare the vehicle for acceleration, not slowing.
It's also worth noting that manually downshifting an automatic transmission out of overdrive is often the only way to utilize engine braking due to the fact that in overdrive, the torque converter clutch and/or the overrun bearing/clutch in the transmission effectively disconnect the drivetrain from the engine in an effort to improve fuel economy when you are coasting.
Q: Where could I sell motor oil that I've been keeping since 1962? Some of them are straight weight — 30W, 10W, etc. Can oil that was bought in the 1960s still be any good?
A: Fun question. Like you, I still have several quart containers of Quaker State 30W and 50W from the 1970s. We used the 50W in race car engines and the 30W in manual transmissions.
Notice I said "containers," not cans. These are cardboard containers with metal tops and bottoms and show some staining on the cardboard due to seepage over the decades. I'm sure the oil is still good and have used some of it over the years to top up my lawn mowers and other small engines. The oil is not suitable for any of today's motor vehicles because of its very early API service rating — likely SC ('67/earlier), SD ('71/earlier) or SE ('79/earlier). Today's engines require an API service rating of SN, introduced in 2010.
