Hey guys so I brought in my 09 g37x coupe to the dealer the other day to some tests done and they found that my left cat is loose internally and I have worn U-bolts. They recommended replacing the driveshaft for the u-bolts and replacing the left cat. Anyone know what these mean in terms of how bad it is? And are these the measures I have to take because it seems pretty extreme to pay 2.4k to fix them both... Thanks!

 

well cats through the dealer is going to be really expensive, i am sure you can find one in the for sale section. If you are handy with tools, you could prob change the cat yourself. the u-bolt i have never changed so not too sure how hard it will be the change.

 

Yea brought my g37x in to have clock fixed and transmission reflashed and they found like all these random stuff. Wanted to charge me 4.2k to fix everything and im like no thanks. They wanted 1.2k for the cat alone and then another 1.2k for the u-bolt replacement.

 

there are no u-bolts on a g37. i am more than positive they are referring to the u-joints along with the driveshaft. if anything get the u-joints taken care of first as that can pose a great risk for additionl damage to your vehicle if the u-joints break apart or seize up. the u-joints can be replaced without replacing the entire driveshaft.

 

While it is technically true that the U-joints can be replaced without replacing the driveshaft, they are the staked in style. Your typical shop is not going to have the needed equipment to replace these. The standard procedure is to R&R the whole driveshaft and send back the old one as a rebuildable core.

 

what is the dangers of having worn u-joints? like if I don't get it done what will happen?

 

I'd get a second opinion. Dealership said my brakes and rotors were warped when pads still had 60% life left on them...but if there is an issue - catastrophic failure and likelihood of injury...you'll be dragging your sh*t under the car like Paul Walker in the first FF. If there is an issue you can't mess around with this.

Is there clunking or vibrations while driving?? The car would be shaking with a vengeance. If you want to test, raise the car and take the load off the drive train and give the Shaft a shake. There should be absolutely no play and make sure it isn't damaged. If there's an issue, take to a specialty shop who has done the repair before.

Edit: As for the Cat, buy one on here or from a vendor, take to exhaust shop $100 later you're done. My honeycomb fell apart and was so loud it sounded like rod knock. As soon as it was replaced the issue was gone

 

Worn Ujoints wouldn't necessarily cause a lot of in cabin noise or felt vibration. But any mechanic could certainly diagnose it so a second opinion would be easy to get.

As for not replacing it - it could be fine as is for years to come or it could suddenly fail and take out a minivan full of kids behind you. Obviously the latter isn't especially likely but I would certainly prefer the parts to be in good shape.

 

Well there are vibrations but I associated them with the exhaust and the fact that I didn't have the reflash. I just got the reflash done and getting the car today so hopefully that fixed some of it. The car seems bouncy could that be associated with the u-joints? yea the dealer wanted to replace the entire drive shaft so im assuming it must be bad. I am bringing it to my friend who's a mechanic to see what he sees/ what he can do

 

so what would I feel to know that the u-joints are worn?

 

I think you're already experiencing it. I wouldn't let the dealership touch my car though. There's most likely a specialty shop, or a shop that stands out, in your area that I'd take your car to before the dealership.

 

You just have to get under the car and feel them. Like RMB said, they should feel nice and tight, without any play.

 

Seems like a simple check really. Jack up, put car on stands - all weight off drive train, Crawl down there and give the shaft a shake....

 

Yea my friend is a mechanic im taking it to his shop tomorrow to see. But if they are worn I have to replace the whole driveshaft? that's what the dealership recommended. I cant just replace the bolts?

 

My honest opinion? I don't know. But, from what I've read, no you can just replace the "+" in the middle. Their seals start to wear and bulge which allows for the play. Typically, they drop the DS and repair the "+" and reinstall. Shoot, there's youtube videos of rednecks jacking up trucks and jeeps doing it in their back yard....I'd hope a seasoned mechanic can fix it without just saying "screw-it" and replacing the whole thing. You could do that yourself so why pay them to do it...It's kind of a lazy cop-out in my opinion.

Then again, I have no idea where the U join is damaged and what parts actually need to be replaced but if it's the typical U-joint replacement you can replace the "+" between the joints for $23.00 for the part and 1-1.5hrs worth of labor. You'll have to go universal since I don't think Infiniti sells them separately. Probably why the dealership wanted to replace the whole thing. If you're willing to put down the scratch though, you can go aftermarket and get a one-piece aluminum one and have it installed for around 6-700; pending how good of a friend you have there

Plus, you won't have to worry about another failure since the aluminum used is strong and lightweight so win-win....Here you go:

http://www.driveshaftshop.com/import...num-driveshaft