Rear End Noise
 

Rear End Noise while cornering hard. Thought it was from the axles but they have been replaced as has all suspension and coil overs. Will only do it while turning left or right while the gas pedal is pinned.So I guess its the differential ? The car is at the shop getting a new motor installed so its a good time to check it out. Anything I should look for ?Thank you all so much..!

This sounds like normal operation for a LSD. Does your car have one?

I don't think its limited slip.Is there any to know without opening it up?

With rear of car on jackstands and in gear, grab a wheel and rotate. If open differential the other wheel will turn in the opposite direction. An LSD will attempt to rotate the other wheel in the same direction.

You can check your option codes under hood. If factory should have IIRC code 220.

It is an open diff.

Wheel bearings

Look for the receipt, I don't think any 986's came with limited slip.

Worn center motor mount can cause these noises as well. Mine sounded like a bad CV joint when cornering hard. With new mount the noise is gone. Since your getting a new engine i'd imagine that's the perfect time to install a new mount.

Same noise issue
 

I too replaced the complete drive shaft CV joints, all suspension parts AND last weekend I did both rear wheel bearings. The only thing I haven't done is to replace all the bushings for the swaybar.

How difficult is replacing the center motor mount? Is this a DIY type of project? I do have access to a full lift and tool system.

Thanks
Thom

center motor mount is a DIY. Forewarning that getting the mount in & out around coolant lines is a total PIA, but can be done.

Having a lift makes it WAY easier. If you remove the plastic clamps (carefully) securing the coolant hoses at the center, that helps. It also helps to remove the 4 chassis bolts completely. It’s takes some wiggling, but is very doable without disrupting the coolant connections. Also, the upper bolts on the engine do not need to be completely removed either. If you look at the mount you can see how it is designed.

+1 ^^ What he said. ^^