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[88mustang351c]

Yes i just installed a different transmission in my 88 ford mustang lx. I have a 351 cleveland in it with a c4 tranny. Now it makes a rapid knocking sound. It doesnt make the sound when the car is idleing. You can only hear it after the idle but when you give it more gas it dissapears. What could this be?

[bling]

Usually, if this sound is of very short duration it is because you replaced the filter. The oil filter on your engine has incorporated an anti-drainback valve which, once removed, removes oil from your engine passages that usually remain filled with oil. Upon starting the engine, it may take several seconds for oil pressure to reach normal levels and achieve quiet operation.


Note that on most fuel injected GM vehicles, the engine should not start until acceptable oil pressure is achieved and this noise indicates unacceptable quality of oil is being used.

Many modern engines made by European auto makers (notably MB and WV) require very specific properties in engine oil. Be sure that you are using an oil that meets the manufacturer's specifications.

If you have a Hyundai 4-cylinder engine and the noise lasts for more than about 3 to 4 seconds you may have an internal engine problem. If the noise persists for a few days or longer, consult with a mechanic.

On many vehicles with hydraulic valve lash adjustment (hydraulic lifters or hydraulic rockers) you should not change the oil with a warm or hot engine. If you do so, avoid any highway driving until the engine cools down to ambient temperature. Noise may indicate that you are damaging the engine's valvetrain.