My 02 Monte has a Knocking in the transmission when the car is warmed up to normal operating temps, Only does it at idle, in gear, park and netural, when i throttle up it goes away. Any idea's?

 

Never heard of this before... can you take a video of it? I know when a flex plate cracks they make a sound similar to a rod bearing knock.... if I remember correct if a flex plate cracks it makes the sound all the time though.

 

thats been my experiance as well...I took the dust cover off and rotated the flexplate..no visable damage or cracks and blots were tight

 

when I get home the morning after driving home from work i will record a sound bit...and post it..was on my way to bed...and I have to let the car run for 10+ minutes to get the noise to start

 

this really dont sound like a flex plate then..... looking forward to hear the video.

 

heres the sound of the knocking. Sorr for the delay had to replce an alternator on my sons truck, also had another 5 inches of snow drop which means yet again moving snow can't wait for spring

 

That sounds like an upper engine valve tick or sticky lifter as my best guess.
According to your profile, you have a 3800? I know the 3400/3100 engines have a valve tick, but not the 3800.
Revving it up seems to cause the tick to go away.

First question:
Is the oil filled to the proper level?
Second question:
When was the last oil change?

If the oil is low, top it off. If you are due or past due for an oil change, get it changed. I would consider throwing an additive in such as "Motor Honey" or Rislone. I'm not saying this will solve the problem. The theory I'm working on is that these products normally include a cleaning agent. If their is a block or something gummed up, they might help relieve that issue. This idea worked on a 3100 my wife used to own. Throw the additive in, noise went away, change oil, noise came back, re-add the additive, noise went away. I did that cycle about 4-5 times (changing oil every 3,000 miles) and finally, the noise stopped completely without need of an additive. Drove the car another 2 years until finally selling it.
Takes about a day of driving for the additive to work through.

If the noise DOES not go away in a day of driving with the oil additive, then I would consider taking it to a professional to evaluate.

 

I know it sounds like an engine issue, but i know for a fact its not, I have been under the car while its running trans. dusk cover off, without a doubt it is comming from the trasmission. I am 100% sure of that, i have again been under it since the first time. may be a balance weight missing on the flywheel/flex plate there is a nickle size dis-coloration from the rest of the flywheel, it had a 3" long weight at the top end of flywheel and 180@ below it a nickle size discoloration like something was there but not anymore. ( alittle more about me, been a mechanic for 25 years, So not knew to troubleshooting, but never had this sound come from a transmission )

 

sorry for spelling on last reply..and correction on the 3" weight....I said it had, I meant it HAS a 3" weight on "top" end of flywheel and a dis-coloration on bottom end of flywheel its round and about the size of a nickle...maybe a quarter. The flywheel has a rust color to it and the dis-coloration is a much lighter color

 

Unfortunately, the sound bite only give so much information. Have you tried the rev test with the car in neutral? To my knowledge, neutral disengages the trans all together. If you are still hearing the noise, then I would think it's engine side, not trans side.

Also, have you tried using a mechanics stethoscope? That could help pin point where the noise is the loudest, giving a better idea of the region to look at.

I'm curious what the issue is, as I'm at a lose right now.