Winnipeg Free Press

Neutral transmission can aid in slippery stops

Question: With the amount of storms we have had recently, the roads are often slippery. I do mostly city driving and one tip I received from a co-worker was to shift the transmission to neutral when approaching a red light when the intersection could be slippery.

He says it works for both automatic and manual transmissions.

I tried it yesterday on a side street, and this morning, and it seems to work as advertised. It took 10 metres rather than 16 metres to stop from 40 km/h.

My vehicle is a 1993 Plymouth Grand Voyager with 294,000 kilometres. The transmission was recently overhauled at a Chrysler dealership.

Are there any long-term transmission issues with constantly shifting from drive to neutral, and then back to drive?— Tom

Answer: The driving tip is a good one, and I often shift to neutral when stopping at slippery intersections. It allows the brakes to work evenly on all wheels during light to medium brake application, without any influence from engine torque.

The vehicle will usually stop shorter and straighter. If you have to stop harder, ABS braking systems will keep the vehicle in a straight line and allow you to steer. But do increase stopping distance slightly, because they have to release a wheel brake momentarily to maintain directional control. Even during ABS braking stops, it does make it quicker to stop on very slippery roads if the transmission is not in gear. Shifting the transmission in and out of neutral will increase wear on the transmission a little and brakes are cheaper to replace than transmissions, so I use this technique only when needed. But it is a good one to use.

Question: I drive a 2003 GMC Sierra pickup with a 5.3 litre V-8 engine and automatic transmission. About eight months ago, it was involved in a front-end accident. It sat for a couple months before a body shop fixed the truck. Since then, the truck has not worked right. It starts fine, but has no power when it is cold. The check engine light comes on and the code is for a cylinder imbalance. But the truck runs fine most of the time, it just uses a lot of fuel.

I have had the spark plugs, coils, plug wires, fuel pump, oxygen sensors and even the intake manifold changed. The cylinder cutout feature has been disabled by my local mechanic while we are trying to figure out what is wrong. When he looks at the scan-tool information, all the data appears fine, other than the cylinder imbalance code, which keeps coming up. But all the cylinders seem to be firing evenly. Do you have any ideas?— Mark

Answer: Whenever I run into a problem like this, where everything looks fine but the vehicle doesn’t work right all the time, there are a couple of things I always look for. The best clues you have are that the truck uses lots of fuel and that it has poor power when cold.

The first is to check all the electrical ground connections between the engine and the body. There may be corrosion at the connections that is causing the problem or there could even be one or more left off by the body shop when the repair was done. It is critical on fuel-injected vehicles to have a good ground connection between the engine and the body and to the battery negative terminal.

The other thing to check is the oxygen sensors. Were the correct ones installed? Sensors may look the same, but there is a difference in oxygen sensors and some of the aftermarket ones are “generic.”

They may work in some vehicles, but not all. If the sensor is sending an incorrect signal, it can still appear OK on the scan data, but is really telling the computer to deliver the wrong amount of fuel. This would cause both symptoms you are experiencing. This is a good starting point and hopefully will fix your problem.