1995 Regal loud transmission noise in P or N

[jmikef21]

I have a 1995 Buick Regal with a 3.1 liter and 4t60E transmission. It has 180,000 miles on it. I have a very loud noise when the car is in park or neutral and you rev the engine above 2000 RPM's. Does not make the noise while in Drive or Reverse. It sounds like metal hitting metal, fairly solid sounding hit. I have looked at the flywheel and torqu converter as best as I could through the inspection plate hole. Everything looks fine there. It sounds like the sound is coming from the transmission. Transmission shifts fine and has no problems while driving.

Any ideas or suggestions would be greatly appreciated.

Thanks

[HotZ28]

Do you here the sound when the engine is revving, or immediately after letting off the throttle?

[jmikef21]

Originally it was just doing it when I held the throttle steady. Now it does seem to be doing it more when I let off.

[HotZ28]

Does it sound like someone hitting the trans case with a hammer? A loud metallic pop?

[jmikef21]

yes thats what it sounds like.

[HotZ28]

Well, unfortunately this is the internal drive chain that is loose and trying to ride up on the sprocket. You can continue to drive it without a problem, just refrain from freewheel revving the engine in park & neutral without a load on it. I drove one like that for five years without a problem! BTW, with 188K on the clock, a rebuild is not too far in the future anyway.

[jmikef21]

So why is the chain spinning in neutral and Park ? Shouldn't it just run in one of the drive gears. Sorry just trying to fully understand what is going on inside of it. And as far as a rebuild yes I think I am extremely lucky it has lasted this long the one in my 1995 Grand Prix I used to have only made it to about 150,000 miles.

Thanks again for the information

[rhenning]

Hey jmikef21:
this loud "snap/pop" noise coming from within the transmission can be
the LOW/REV band "self energizing" This happens when the band is worn.
It tips to the side, and is caught by the rotating drum. The noise stops in
all other ranges because it is applied.
I have seen this, and repaired this condition several times.
Good Luck, rhenning.