So I am removing the driveshaft from my '83 Rx7 and I already pulled the engine and transmission off of the driveshaft and out of the car. The driveshaft is not only connected to the vehicle at the rear axle. I have attached a photo of what it looks like.

I have removed the four bolts holding the driveshaft flange to the differential. It will not budge an inch from the diff. I have attempted to hit the driveshaft with a mallet to free it. I have tried soaking it in PB Blaster (generic penetrant). Nothing will get the driveshaft off of the diff. I simply cannot pull it harder than I have already tried. I tried using a jack to lift the driveshaft by the rear u-joint in an effort to break the two loose. No luck, the car will literally lift up with the driveshaft still stuck to the diff by what I assume must just be rust welding. Any tips/tricks for what to do here? I could try a flame or something but I just cleaned to floors so I don't want to cause a chemical fire at the moment.

You can see in the photo that I've already pulled the 4 bolts from the driveshaft... it is still stuck in place.

 

tap it with a hammer

 

A pry bar will fit in the gap between the u joint and the pinion. You can pry it off pretty easy. Might not be too well for the u joint, but neither is beating on it with a hammer.


EDIT: I see now your trans is out. Just walk the drive shaft from side to side. Shoot that's a good enough pry bar as any.

 

^ what he said. Also, a cold chisel in that gap and a bfh

 

Had the same issue when I removed my original driveshaft.

A small chisel and hammer worked very well to seperate the flange. It will deform the surfaces slightly so clean them up after with a file.

 

I sanded both sides of the flange after getting it off. I then put anti seize on it to prevent that in the future.

I used a chisel as well.

 

I'm always reluctant to recommend hammer mechanics, but a few good solid raps with a big brass hammer would help bust it loose. The weight of the brass gives it power while its also softer than the steel to help prevent damage.

 

You can also try a dead blow hammer. Gives a good 2 for one hit.

 

Dead blows are good for seating things together. They absorb part of the striking energy and are less prone to bouncing. The weight / power of a brass head, sends a penetrating shock through parts, which helps separate parts that have corroded and grown together over time.

 

if the hammer and chisel doesn't work, the last resort is heat. Get a >FIRE EXTINGUISHER< and a propane benzomatic torch or a MAPP torch (if you want to nuke it). The penetrating oil is flammable. I'd spray thing down with a heavy detergent and rinse everything off first. Get it good and hot, then wack it with the hammer and chisel.

Then there's always oxy-acetylene. You can cut steel with that.

Befoe you do all that, try a cigarette lighter with the FIRE EXTINGUISHER near.