I have a Chevy Suburban R2500, 2WD, 454.
When I am traveling on the freeway, at approximately 75-80 mph, the engine begins to give off a pulsating moaning sound. If I reduce the RPM's, the noise disappears. There is no vibration felt. Could this be the harmonic balancer? If not, any ideas?
Thanks, Andrew
It is moaning while trying to warn you to slow down before you become a ghost.
You didn't give the year. Exhaust resonance is my guess. Maybe resonance accentuated by rusting thin exhaust pipes. Tires are a maybe as is a wheel bearing or u-joint, but those aren't usually specific to that speed and have other signs as well.
I would add the possibility of noise from the A.I.R. pump. If it didn't pulsate I would check the tranny filter. The air cleaner intake could also cause some moaning as they are very restrictive.
It's a 1990 Suburban without A.I.R.
There is as newly rebuilt trans and engine installed and a K&N filter. The exhaust is also new with a Flowmaster Big Block II muffler and new cat. Does this help?
Thanks, Andrew
not really bro, sorry
I still stick with exhaust resonance. That's allot of engine and if its like mine, the tailpipe is a fairly long one. Try installing a resonator tip to the exhaust, see if it helps.
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