Question: I recently bought a 1977 Ford LTD. I put the car in park on a steep hill and had trouble releasing the transmission shifter. A couple of weeks later, a grinding noise started. I eventually had to have the transmission rebuilt. Shortly after that, the grinding started again. What is the problem?--M.R.M.
Answer: Any time you park a car with an automatic transmission on a steep hill or incline, you are running a risk of transmission damage if you don't exercise a lot of care.
The park position on a transmission works by inserting a metal arm, called a pawl, into a gear, which jams the transmission and keeps the car from moving. It is designed to hold the car on relatively flat surfaces.
If the car is parked on a very steep hill, the pawl or gear can be damaged and will eventually require costly transmission repairs. The difficulty of pulling the transmission lever out of the park position when the car is inclined indicates that it is being over-stressed. If you frequently park on a hill, possibly you have damaged your second new transmission.
The problem can be avoided by setting your parking brake on steep hills before you put the transmission into the park position. Also, when you are ready to drive away, be sure to shift the transmission to neutral before releasing the parking brake.
Q: I have a 1984 Nissan King Cab pickup. I recently had a 7,500-mile service job, which included adjusting the valves. The next day, there was a loud clacking noise when I started the engine. The noise also occurs at speeds over 45 miles per hour. Will this damage the engine? The mechanic said not to worry.--R.R.
A: Nissan engines do have a condition called start-up rattle, which occurs for a few seconds after the motor starts. The noise comes from moving parts, such as the cam shafts that operate the valves, before lubrication can be pumped up from the lower engine.
You did not say whether you had the service done at a Nissan dealership, but Nissan oil filters have a valve that prevents oil from draining down into the lower engine when the motor isn't running. Some replacement-type oil filters apparently do not have this valve, and that can exacerbate the rattle.
Nissan doesn't think the condition of start-up rattle will cause excess engine wear. But if the noise is occurring at medium-speed driving, you may have a problem. Have your mechanic recheck the valve adjustment and look into the problem.
Q: For the last year, our 1980 six-cylinder Oldsmobile Cutlass has made a fairly loud groaning noise at moderate speeds. It comes from the engine compartment, just behind the glove box. It seems to help if we turn on the defroster blower. We've brought it to the dealer twice, but the effect was only to make us $600 poorer. Can you help?--J.A.R.
A: You may be only masking the noise when you turn on your blower motor, or the blower motor itself may have worn-out bearings or bushings. When a motor wears out, it tends to rattle.
Another possible cause of the noise is a relief valve on the air conditioner. When the air conditioner in the car reaches a preset temperature, the valve recycles gas through its internal system. That can cause a groaning noise as well.
Ralph 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.