Q: We have a 2009 Chrysler Town & Country with 63,000 miles on it. It has a relatively violent shake when you apply the brakes that is getting much worse, especially on the highway at speeds over 30 miles per hour. I have had the wheels checked and retightened with no luck. I don’t see any enlargement of the lug holes. Could this be wheel bearings, brakes, brake rotors or what? The vibration starts in the steering wheel but at upper speeds the entire van shakes. Having a disability, it’s important we have a safe van. What do you think it may be? Should I take this to our dealer or a specialty brake shop? We do have a Chrysler extended warranty.
A: The most common cause for a heavy vibration when the brakes are applied is warped or worn brake rotors. Has the vehicle been in a crash or curb/pothole impact? Any bent or damaged wheel, tire, steering or suspension component could contribute to this. Steering rack mounts and worn inner tie rod ends are also possible causes. Even worn McPherson struts/shocks could allow minor vibrations to amplify dramatically.
I would suggest a complete brake, suspension and steering component inspection as soon as possible. Since you have the extended warranty the dealership might be your best choice, although brake components are considered normal wear items and would not be covered.
Q: I have a 2014 Honda Civic with a CV transmission that feels sloppy. If I am rolling backwards slowly (e.g. 1 mph) and shift to drive, it takes at least two full seconds before engaging. This often startles me and feels dangerous. I asked about it at the dealership and they said it was normal. What do you think?
A: I don’t think you should shift into drive while rolling backwards at any speed. Regardless of type of transmission, trying to engage drive while moving backwards is never good for the transmission. It may not be catastrophic, but the engagement impact certainly creates more mechanical stress. In an automatic transmission this action applies hydraulic pressure to a drive clutch that is rotating in the opposite direction, causing a somewhat sudden and violent engagement. In CVT — continuously variable transmission — the belt/chain rotating in one direction attempts to engage the sheath/clutch that is rotating in the opposite direction, creating a similar sudden engagement.
I suspect the result of this type of engagement is normal, but the fact that it “startles me and feels dangerous” is a not so subtle reminder not to do so.
Q: I have a 2013 Toyota Tacoma pickup. It is a two-wheel-drive model with the four-cylinder motor and five-speed manual transmission. With a little over 40,000 miles the tires need replacing. The original size tires are 215/70/15 and I would like to replace them with a set of 235/75/15 that I have on hand. I have done this on previous Tacomas I’ve owned with no problems, the last being a 2004 model. Given today’s more complex computer systems (ABS, etc.) can I swap tires without fear of damage to these systems?
A: As long as all four tires are the same size, yes. Since ABS, traction and stability control systems monitor relative wheel speeds, this will not change if you install the larger tires. In fact, Toyota offers larger wheels and tires for your vehicle, as do many aftermarket suppliers. While the swap won’t damage anything, the P235s are about 7.5% larger in diameter, meaning the speedometer will read low — the vehicle will be traveling faster and farther than the speedometer and odometer read. The larger tires effectively result in taller gearing, meaning lower engine rpm at any given true speed. This may affect available torque, shift points and pulling power to some extent.
However, since you’ve done this swap on previous Tacomas, you’re already aware of the driveability differences.