I recently started to get (well it's more of a DINK DINK DINK than a knock) that gets louder and more rapid with rpm increase coming from my 1972 c4 transmission. It doesn't happen in neutral and is most prevalent between 700 & 1,500 rpm which makes me think converter? I've checked the universal joints, replaced the transmission mount, and pulled the starter to look at the teeth on the bendix and flywheel, all of which look good. There is a small amount (very small) amount of play in the drive shaft if i push up and down on it from the ground, but doesn't make any audible noise when I do so. It will do it in drive with my foot on the brake, but as soon as I put it in neutral the sound stops. The problem also only seems to start once the transmission is warmed up completely (I'll drive a mile to the store after letting it warm up for a few minutes and it'll be fine... I'll come out in five minutes and it'll do it half way home). Anyone have any ideas or have had this happen to them? The transmission seems to be shifting fine, but there is a very light "dink" sound when it down shifts (same sound, but much more quiet). The truck is also very sluggish when you step on it which has definitely never been a problem until now! Sorry about the long post, but I'm trying to give as much info as I can! Thank's in advance! Mike.
That is the sound a cracked flex plate makes , hard to see until you pull the torque converter away from it.
Dave Mc is dead on. Had a 66 Pontiac with the same tink tink almost like a valve noise that came and went. It was a cracked flex plate.
Thanks for the reply! Can I get to those through the inspection plate or do I have to drop the transmission? Was feeling lazy after work today so haven't got a chance to look in there yet!
Thank's for the replies everyone! That's why I made an account here, the members here on on the ball!
See if you can get to them through the inspection plate, if not pull the starter. Its been close to 20 years since I had to tighten mine so I cant remember how I did it, I know I didn't pull the trans. Now, if the flexplate is cracked that's a different story.
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