SBF 302 and C4 transmission. Well now another issue came up. All of a sudden at speed (30-40 mph) when letting off the gas/decelerating there is a definite low pitch whirling or winding down sort of noise. Not extremely loud but it's definitely there. Hard to tell where exactly it's coming from. For sure wasn't there before today. Not when braking, just letting off the gas and slowing down. Something seems off. Don't have the car with me. Left it at a friend's house. It's being towed here Sunday since it's going to rain the next couple days. Having it towed because it was 20 miles from home and didn't want to risk it. Thoughts? Driveshaft? U-joints?
You might try running it up to 40 and shifting into neutral and see if the noise is still there. That disconnects the engine and torque convertor.
Check the wheel/axle bearing's too. Does it do it while accelerating and you just haven't noticed it yet?
Car manuals used to have a rear end gear noise diagnosis chart in them, very handy to have. It would be nice to rule out the rear first off. Get that out of the way. Things that come to my mind are a possible bad axle bearing or loose pinion nut. Both easy enough to check.
Not sure if it's happening when accelerating as the engine would drown out the noise. As soon as you let off the gas the engine itself naturally is much much quieter which is when you notice the noise as you slow.
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