Again: LSD oil

[danielvanderwoude]

make sure you use oil with lsd supplement

Does your fillerplug open? If not it will be hard to fill up ;-) so first loosen that one. The heating trick is to get is expand and when it cools down again it breaks up the rust in the grooves. You can also accomplisch that by hitting it a couple of times very hard with a big hammer.

But since it is the bolt in your oil filled diff I don`t think it is rusted inside actually... You just need more power in your arm or extend the wrench. To prefent the car from falling on top of you it might be a better idea to put the car on the ground and crall underneath it, or you can put the axle stands under the axle and not under the car (I believe you have that at the moment?). But again, first get that top bolt loose!