So I did my full l67 swap and 4t65eHD swap out of the 05 Monte parts car I had I did the swap and the engine had 91,3xx miles. It has about 92,500 miles on it now. The first 800 miles were smooth as silk, no noises, no problems. Well the other day I was driving, and going down a smooth road and heard a little pop or clunk from the front drivers side. I let off the gas and instantly heard a whining sound and as I got closer to 10mph it sounded like a bicycle chain as it's going over a sprocket. On my ride home it started to get a little quieter, eventually the "bike chain" noise went away. But now since then all it does when I let off the gas is whine and whine and whine. I can hear it over the radio, it's a very high pitched whine. Anyone have any insight? I tried doing some searching but not to much came up. Thanks

 

Just a shot in the Dark on this one but, have you checked the Power steering pump, and another thing that you may want to check is the Idler/tensioner pulley, some where on the serpentine belt area.
A fellow I know had a similar issue and it was a pulley but I don't recall which.
Hope you find it?

 

Power steering is good and all pulleys were replaced when I put the engine in about 4 weeks ago. It's definitely on the drivers side front of the engine, and it really only makes the whining noise when I take my foot off the gas and it coasts. I did some research and I see people having an issue with it whining on acceleration from being either overfill or a pressure sensor. But mine doesn't whine accelerating, only taking my foot off the gas and coasting I'm Confused here

 

Perhaps it is an issue with the bearing or the axle on that side?

 

That did go through my head, but it doesn't sound like a typical wheel bearing rumble and it stops when I reapply my foot on the gas. This is my first and only FWD vehicle, I'm used to RWD and the noise I'm getting from the front left side is identical to the noise a bad pinion bearing makes in a RWD axle It's a high pitched whine. That's why I'm confused.

 

Check the axle and your transmission fluid

 

Sorry I haven't responded. I forgot my login passwords. Problem with car is still there. Whine has gotten much louder. Haven't had much time to look at it been crazy at work. Going to try later today or this weekend. It's overpowering the radio now....and as I stated before. Only on deceleration. It sounds just like a bad pinion bearing on a rear axle.....hoping it's not transmission

 

Whining is either the alternator or the transmission in most cases, unfortunately.

 

Cut a Fiberglass Driveway marker to a length of 40" (Forty inches).
Grind one end to a dull point.

Hold this tool in your fist, ... with your Thumb upon the flat end.
Touch the POINT of the tool ON or near where you suspect a strange rotational sound might be originating.

Place your EAR to your Thumbnail and "Listen" to the sound coming-up-through the rod.

Play Doctor.
Listen to the engine, H20 Pump, Pwr Str Pmp, and Alternator.

If something's acting-up, ... you'll hear it.