i have an 86 gxl fc, i have an irregular sound ocming form the back half of my car when i push it and it hits 55 mph it makes like a deep rumbling noise and i've tried to research it and i think it may be loose bolts on the drive shaft haven't checked, also when i shift sometimes it makes a sound like 2 metal objects hitting against each other i hope these 2 are related and easy to fix but please help me out i'd greatly appreciate it

 

Probably a completly worn out mount on the differential or transmission.

 

is it bad to keep running it like that? and where are the mounts located im new too all this

 

the car is only as good as you want it to be.
If you want it to fall apart..ya,don't fix it.
BUT,if you want it to get you from Point A to Point B,Reliably,,then Jack it up and get Dirty.

 

i do want to fix it and im always willing to get dirty for my car, but where are the mounts located? dont want to mess with something else, pic's would help too!

 

could be many things good luck. i would pin point what it was before replacing stuff

 

The first step will be to familiarize yourself with the car. Get a Haynes manual, download the factory manual (FSM), jack the car up, and start taking a look around. The mounts are in obvious locations ON the transmission and ON the differential.