i need help with backacks for my bmw e21

it have sound when i stop and move again with the car like there is some space in it so it make sount so can i fix it? or change it? or what please

i mean that

Hi Jyad :-)

It is either your rear bushings that need replacing or, as you say, some space in the gears in the differential. It is very common in older diff's and is not so bad, it is just annoying.
I have the same problem with mine but have learned my self to drive so it can't be heard or felt.
The only way to solve the "problem" is to change the gears in the diff or the intire diff. I don´t find it necessary on mine because it is quite expensive and the gain of fixing it is small...

oh ok thanx
u know i have another gears but when i clean my garage i throw it away ahahaha i dont know that i will need it some day
it's not a big problem that sound it's ok thanx
im thinking about put greasy not oil in it is that will be ok?