I reinstalled my rear subframe after replacing the fuel lines and noticed when the two rear differential mount nuts were torqued, there is a gap about 0.25". Check the picture. Is this normal? It's like this on both the left and right mount.

 

No, that is not normal. I encountered the same issue when I dropped my subframe as well. Take the rubber mount off, clean the bottom of the threaded bolt with a wire brush, making sure there is no rust or cross-threading interrupting your process. Now take a look at the nut that screws into the bolt, make sure that its not cross-threaded either. Check and see if the nut goes up smoothly, if it does, then it was just rust. If it still doesn't go up, then try re-threading the nut with a tap (that's what solved my issue). Its one or the other, don't force the nut in cause you might strip the thread on the bolt and you'll get yourself into a world of trouble.

 

I had the same thing happen when I was reinstalling my subframe. I double checked the stud and he nut and everything, it all seemed okay. When I put the car on the ground, the gap closed up somehow . I'd drop it down and see what happens, let it sit for a while, then raise it again and re-check.

 

Do you remember the tap size?

 

I'm pretty sure it was M12 x 1.25...

 

I noticed the same thing on mine, when I installed the pionin subber a few weeks ago.

 

Ya Me too.
I am wondering if I should put a couple washers below the Mount Cups to bring them closer to the Diff.
I get what I call "backlash" when the car is driving with no foot on the pedal,sort of thing.It Bucks.But the engine is running fine.It is in the rear only.
I may install a Snubber in the spring,and see if that takes it out.