Rattle noise on cold start & going from forward to rev.

[Instigate]

I have a 79 1Ton with 350 engine Quadrajet carb and an automatic trans. I can't remember which one but I will identify and update tomorrow or the next day if it really matters. The symptom I am experiencing is a loud rattling noise on every cold start and most of the time when I go from forward to reverse or vice versa. The noise stops when I start moving forward or backward. Or on the cold starts I make it stop rattling by immediately putting it in reverse then back into park until its warmed up. If anyone knows what is causing this I would appreciate any info. Thanks.

 

[79K10]

maybe the heat shield by the cat, or the cat itself it going bad ... if it does it in park on cold start, climb under and see... could also be a broken exhaust hanger

 

[bucket]

Could be a cracked flexplate and/or loose torque converter bolts.

 

[Instigate]

Could be a cracked flexplate and/or loose torque converter bolts.

Thanks for the reply. I'll take a look at that.