Front drive shaft vs Exhaust

[stumblnyj]

I recently been hearing a loud knock coming from under the front of my YJ. I found some rub marks on the front drive shaft that look like the exhaust pipe is hitting it. Everything looks to be connected correctly and I havn't done any work that would have loosened or moved the the two parts.

Further inspection I found that the small transfer case mount needs to be tightened. I did and I still get the knock. It only happens on turns and it sounds like the exhaust pipe is climbing the drive shaft before popping off and making the noise. Can anybody help me with this? What is causing this? Is there an easy cost effective solution? With out replacing and rerouting the exhaust I can't think of anything else.

 

[808CJ7]

Did you try to move the exhaust by hand to see if it was loose? If your transfer case mount was loose you may want to check your engine mounts also. Inspect all the fasteners and see if there's any play in the driveshaft.

 

[69jeepcj]

^^^^engine mounts would be my guess as well. check the brackets that the engine mount bolts to also. I found mine cracked in half.

 

[stumblnyj]

^^^^engine mounts would be my guess as well. check the brackets that the engine mount bolts to also. I found mine cracked in half.

How exactally do I check to see if the motor mounts are bad? I know if there is no rubber then they are toast. But mine appear to have rubber in them with the drivers side having a little less. 69JeepCJ are you reffering to the bracket that attaches to the frame?

 

[69jeepcj]

Yes im referring to the brackets that attach to the frame. Mine was cracked in half and i had to reweld it last weekend. best way I check the motor mount is get a big bar that will fit under the motor mount and pry up hard and you will see if the motor lifts up on that side or not. The rubber may still be with the mount but the rubber can be slit in half. when using a bar to pry up you can see if the rubber seperates.

 

[superj]

Yup, cracked rubber mounts will let you sag and hit the exhaust, also, the main trans mount being bad will also.

 

[stumblnyj]

Ok I finally got to checking the mounts. The passenger sidemetal bracket is cracked all the way through. Should I replace bothpassenger and driver sides?

 

[808CJ7]

I would replace both. If one side is broken, the other side is ready to go also

 

[69jeepcj]

If it was the bracket coming off of the frame, I would just replace that one. If it was the metal mount bracket that the rubber sits on, then I would replace both also.

 

[stumblnyj]

Thanks all, I will be getting the parts today

 

[stumblnyj]

Ok I just looked up the part..... The part that is broken looks to be a mount between the motor mount and dog ear of the frame. Anybody know what that might be called?

 

[69jeepcj]

can you take a pic of it? The rubber nount comes molded to a steel plate for the bolt to go through, that mounts to the frame horns which is what it sounds like you are discribing. If its the part coming directly off the frame, its called a frame horn. If you can weld, you could just weld it back up or take it to a welding shop should only be about 20 bucks for them to weld it up while you wait if a new one is pricey.

 

[stumblnyj]

69JeepCJ, Its not the horn but a small metal U shaped bracket the two bolts from the mount connect to. This U shaped bracket has one hole that mounts to the frame horn. I two of the best pics I could with my phone but don't know how to get them on here.

 

[stumblnyj]

Ok here are the pics
This shows the mount on top of the bracket


This shows the crack that goes through the bracket.

 

[stumblnyj]

Ahhh HA!!! I figured it out. Not the best photographer so I hope they can help you

 

[69jeepcj]

Totaly your prefferance. I would just replace or weld the one, but some would feel better doing both. It looks like its not actualy part of the motor mount but supports it.

 

[stumblnyj]

I guess I will call the dealer and see if the part is discontinued or not and how much they want to rape me for the convenience of not having to weld it back together. Thanks to all who helped in my endeavor.

 

[stumblnyj]

Break out the welder!!!! $72.95 to order it from vintage parts. and if anybody needs one down the road the dealer lists it as a motor bracket.