Hello all and let me apologize in advance for the long post. I want to give as much info. as possible. 1988 Blazer 4x4, 4.3l. 700r4, I have a tapping sound that is much louder at the bottom of the engine compartment than at the top. The sound does change in relation to the RPM's. I read all the posts I could that had a similar sound and followed the suggestions given and still have the same sound. I checked and rechecked all the fasteners at the flexplate to converter and flexplate to crank. I seperated the flexplate from the converter and pushed the converter as far as possible into the bell housing. Same noise. I have replaced the flexplate even though I could see nothing wrong with mine.($40 gamble) Still the same noise. I am now at a loss to explain this. The engine seems to have good oil pressure, drivability does not seem to be affected. I say "seems" because I am only reading the OE oil pressure guage and have not had the speed over 40 mph. I have a functioning check engine light and it does not come on to indicate any problem. So far the only things I can rule out are the trans. and flexplate. Any help is really appreciated. Have a good one!!!

 

O.K. all,

Since the previous post I've done some digging. I decided to just pull the motor and replace it with one that I have had for a while. It turns out that my noise was a bad rod bearing. I hope this helps anyone that may experience the same issue.

 

that sucks that you had to take so drastic a step but thanks for updating your post. that's one thing i like most about this place.