A buddy if mine was saying the body of my Xj is fiberglass and I said no it's not buy I'm not exactly sure so I'm just wondering what it is... Aluminum maybe?

 

The bodies are made of steel. Older style XJs (pre 1997) the rear doors were made of fiberglass but the rest is still steel.

 

Ok thanks

 

The only things fiberglass on a XJ are the header panel and rear gate on early XJ's. On later, the gate is steel.

Kick your friend in the junk.

 

Steel stampings welded together - I think they're about 16ga, but may be 14ga.

As mentioned, the liftgate 1984-1996 was made from fibreglas (which gets bloody everywhere when you cut it - I've put oversized speakers in more than a few rigs...) and 1997-2001 is made of the same steel as the body.

The "frame" is welded to the body, and made of similar material (may be one size thicker, I don't know - and several areas are doubled for strength,) which is why you can't get a body lift for the XJ or MJ.