So lets see were to start, i replaced my 4.0 after it died, with a rebuilt 4.0 from another HEEP that is the same year 89. I have been getting some rubbing sound when making sharp turns. When I looked today it looks like my front drive line right at the yoke into the front diff is hitting the exhaust right as it bends to go back to the CAT. I did use the manifold that was with the rebuild, but not the front pipe and all installed fine. So what do you all think do I have a mismatch or a bigger issue.

 

Take it to a muffler shop and have them bend the pipe so it doesn't hit the DS anymore. Shouldn't cost that much to fix something simple like that.

 

Another question would be was it doing it prior to installing the engine. If everything is the same nothing should have changed. But something did change!

 

pry bar, BFH and some elbow grease

 

Pry bar and BFH does work for some exhaust problems some of the time for some people. Just be careful not to dimple or kink it so much that you're causing too much restriction in the exhaust. Even a little bit will hurt your power and fuel economy. A lot will blow your motor up.

 

Similar problem after replacing entire exhaust system. There is a flat spot in the new front pipe but it is too high up on the pipe. I was thinking bend it myself. Any tips? What is the most anyone would suggest bending in the pipe? I don't think I need much, but I don't want to do it twice. Does anyone know how much clearance is required. (I will understand if no one does, kind of a dumb question.)

 

yeah i had a similar problem. it would scrapey scrapey when turning sharp, and in 4wd it would be even louder. it eventually took a toll on the whole exahust system, which just fell off my jeep 30 minutes ago on my way home from the store. the manifold and pipe and cat are still up there but i think the manifold is loose or cracked and is getting worse. the muffler to tail pipe are now in my back seat and my shirt has been sacrificed as a roadside oven mit to grab the muffler and rip it out, so it wouldnt tangle around my rear axle. if you have the bones, fix it fast, im poor so i let it go and now im gonna be poorer. how much does an entire RENIX style exhaust for a xj go for these days? a bajillion?

 

have you checked your motor mounts? I had an 87 comanche that did that, ended up having a broken motor mount, replaced the mount and that solved the problem.