Weird Knocking Noise 81 rx7
 

I got a 81 rx7 It making a weird knocking noise towards the back of the car, i don't kno if it the differential or drive shaft, etc.. I hav no idea wat it is, there is no visible problems. If anybody can help on some suggestions on wat the problem is it would be appreciated.

Check your exhaust. Sometimes the hangers break and the pipe will knock against the bottom of the car when moving.

Could also be a rear wheel bearing, it would be a cyclical noise.

I had the same issue with my drive shaft hopefully that isnt the issue because the univesal joints are not changeable on the first gen. i had to buy a new drive shaft all together. good luck!!!

jack up the rear end and run the car, it will be much simpler to locate where the knock is coming from. just be sure the car is secure on the stands. a car lift would be better but sometimes noises only appear when the suspension is loaded(ie exhaust rattling on the diff).