Shifting Into Reverse Is a Real Grind

Question: I own a 1983 Honda Prelude. Whenever I try to shift into reverse gear when the engine is cold, the gears grind. Sometimes, the only way I can get into reverse is to put the transmission into reverse before I start the car and then disengage the clutch while I start it. I wonder if the car is idling too fast or something. Can you suggest anything?--T.B.

Answer: You could seriously damage your transmission if the grinding is severe, so you have to be careful. You may need a new clutch, and you certainly don’t want to also have to pay for an expensive transmission job.

When you step on your clutch, the transmission is supposed to disengage from the engine. If the gears are grinding when you attempt to shift into reverse, it means that the transmission has not fully disengaged from the engine and its gears are still rotating.

An old trick that is seldom taught any more to eliminate the problem of grinding reverse gears is to briefly shift the transmission into any forward gear and then quickly shift into reverse. The forward gears should stop all shaft rotation in the transmission and allow a smooth engagement into reverse.

The reason you can shift into forward gears and not hear any grinding is that forward gears have what are called synchronizers, which allow the gears to shift even while the transmission is in motion. But reverse gears do not have synchronizers, so if you want to select reverse, the car must be at a complete stop and the engine must be fully disengaged from the transmission.

If the trick of shifting into a forward gear doesn’t work, you most likely have a problem with the clutch. Possibly the clutch plate has warped and does not have enough clearance to separate from the flywheel of the engine.

Or the splines on which the clutch plate slides have become dry and rusty, preventing the clutch plate from floating away from the flywheel. In either case, it is not clear why the problem only occurs when the engine is cold.

Your trick of shifting into reverse before you start the engine is probably safe, as long as the clutch is not so seriously flawed that the car tends to move even with the clutch depressed. A clutch costs about $350 and usually must be replaced every 40,000 to 60,000 miles.

Q: My car is a 1981 Chevy Camaro with a V-6 engine. My problem is difficulty in starting in cold weather because the spark plugs are covered with gasoline. A mechanic rebuilt the carburetor and replaced the mixing valve, but the problem still exists. The car will start if the choke is opened with a clothespin. I was told to idle the engine five minutes before starting out.--S.D.

A: You seem to have a textbook case of a bad choke, and I can’t believe your mechanic hasn’t solved it. If he has not rebuilt the choke, then that should be the first order of business. If the choke is rebuilt and still not functioning properly, you might have the choke converted to a manual operation with a cable that runs into the dashboard. This is a second-rate compromise, but it has got to beat the clothespin routine.

Vartabedian cannot answer mail personally but will respond in this column to automotive questions of general interest. Do not telephone. Write to Your Wheels, You section, The Times, Times Mirror Square, Los Angeles 90053.