Found Cause for Mysterious Clunking Noise

Burly · 10-25-2006, 08:13 PM

For the past few weeks I have been experiencing a clunking noise located under the center console only on quick launches. I have posted this before and have had no luck finding the cause. I took it down to the dealer and the looked at it, and went for a drive with me and blamed it on axle wrap. I never had a problem with that in the past year so I knew that was not it. A mechanic friend took a look and thought the transfer case or slip yoke splines were to blame. He took another look for me today when he got off work and finally found the problem. My rear transmission rubber mount is torn all the way around. I feel much better knowing that the problem has been located. I knew it was something new since the thump is so forceful and located right up front. Now I need to take the truck down to the dealer and have them jack the back of the tranny up and see for themselves. I’m sure more of these will happen in the future, so now we know what to look for.

**P's Titan** · 10-25-2006, 08:30 PM

Quote:

Originally Posted by Burly

For the past few weeks I have been experiencing a clunking noise located under the center console only on quick launches. I have posted this before and have had no luck finding the cause. I took it down to the dealer and the looked at it, and went for a drive with me and blamed it on axle wrap. I never had a problem with that in the past year so I knew that was not it. A mechanic friend took a look and thought the transfer case or slip yoke splines were to blame. He took another look for me today when he got off work and finally found the problem. My rear transmission rubber mount is torn all the way around. I feel much better knowing that the problem has been located. I knew it was something new since the thump is so forceful and located right up front. Now I need to take the truck down to the dealer and have them jack the back of the tranny up and see for themselves. I’m sure more of these will happen in the future, so now we know what to look for.

to help others that are very mechanical, if possible a pic would be nice...

Burly · 10-25-2006, 10:42 PM

Quote:

Originally Posted by P's Titan

to help others that are very mechanical, if possible a pic would be nice...

I will take a couple tomorrow and post them for everyone to see.

Justintoxicated · 10-26-2006, 01:25 AM

Sweet please do ! This will be very helpful.

Burly · 10-26-2006, 07:38 PM

Here are the pics of the torn transmission/transfer case mount. The problem I was experiencing was a series of thumps that could be felt through the center console only when taking off quickly from a stop. In order to see if the rubber mount was torn, we had to jack the rear of the transfer case up in order to expose the mount between the transfer case and the cross-member. Sorry not the best of pics but you can see the tear and where the rubber used to be connected. In the 4th pic you can see the light coming through the tear in the mount.

Burly · 10-27-2006, 06:28 PM

Got the new mount ordered today. The service tech said that this is the first one that he has seen torn on a Titan. He agreed that this is where the noise I have been experiencing is coming from. He had to check with the service manager to see if they would warranty the part since my truck is lifted. He said they would go ahead and warranty it "this time", he claims that my lifted truck puts more strain on the mounts. I'm not sure how he came up with that conclusion.

MattD · 10-28-2006, 12:07 PM

Quote:

Originally Posted by Burly

Got the new mount ordered today. The service tech said that this is the first one that he has seen torn on a Titan. He agreed that this is where the noise I have been experiencing is coming from. He had to check with the service manager to see if they would warranty the part since my truck is lifted. He said they would go ahead and warranty it "this time", he claims that my lifted truck puts more strain on the mounts. I'm not sure how he came up with that conclusion.

For all you guys that have lifted Titans, please remind your service manager that Nissan sells a lifted Titan. There is no possible way that a lift kit would have caused that additional strain.

titan_dork · 10-29-2006, 02:48 PM

It is absolutely possible that a lift kit can cause more stress on the driveline.

The increased driveshaft angles have many effects on the the transmission (especially the output shaft and bearings).
The new angles also have a large effect on the axles input shaft and bearings.

It is very common that with a lifted vehicle it will be suggested to use a double cardon style driveshaft... to allow the couplings to flex to the new angles... and to deal with the vibrations.

One of the main things that has to do with axle problems/vibrations; is to ensure that the driveshaft's angle as compared to the trans, and as compared to the axle, are identical. +/- 1 or 2 degrees is no big deal here, but greater than that and you are guranteed vibration. Has to do with centrifigal forces... and there's no way around it. However the double cardon will "cushion" the vibration a little bit.

When most vehicles get lift kits, they also get the transfer case dropped. Though this depends on the amount of lift, the wheelbase, the original design, etc. But check out a Jeep forum, and you'll see this debated to death.

It's also important to remember that with any lift or alteration in ride height, or change in drivetrain length, etc. will have negative effects. The angles are set at the factory. Especially true with 4x4 vehicles... because as you change the rear... it will also change the front, and vice versa, and lowering or raising the x-case will have negative effects. This is why many aftermarket companies make "transfer case clocking kits" which will sping the x-case to allow the front driveshaft angle to match the rear.

---- and that's just the tip of the iceburg of the debate ----

(and i see no reason why a titan is any different from any other vehicle)

Also:
The titans (atleast mine and other's i've seen) have the slip for the driveshaft(s) where the shaft enters the transmission. This is a terrible setup, and is used only to save production costs. Much better to have a shaft with a built in slip. (see any TJ shaft debate on any Jeep forums, pissed alot of people off).

and:
Titan has a a low pinion rear axle; which is not conducive to lifting. This is because the shaft has that much more of an angle. Could swap in a high pinion axle... and that would be awesome for a lifted titan. (and don't just go and flip your axle over because it will starve the pinion bearing(s) of oil... and destroy it).

oh, and [/rant]

Good luck... i busted the tranny mount and axle on my Jeep no less than 25 times in 2 years with a lift kit. (though that's a short wheelbase and a bit different).

Edit:
I'd also suggest they, or you replace the U-joints in the driveshaft while you're at it. Could very well be that one got screwed up and increased the vibration, and hence broke your mount. Pretty common problem on other vehicles. It's probably 20 bucks in parts to replace the u-joint bearings... al ot cheaper than more tranny damage.

And just to add that the increased driveshaft angle also decreases MPG because you're wasting more energy spinning the shaft in the wrong dirction(the angle).

Also the incrased angle makes the driveshaft weaker... because the lift pulls the driveshaft further out of the tranny... thus reducing the amount of the splines making contact.

HemiHunter · 10-29-2006, 03:46 PM

I'm gonna have to look at mine now. My driveline spline has pulled back from the transfer case 2.0-2.5 inches due to the CST lift. When I punch it the driveline would slam into the transfer case (Axle wrap) sending thunk right up your back. I have since corrected the problem with PRG traction bars but now wonder if I had torn the mount as well.

Burly · 10-31-2006, 05:03 PM

Quote:

Originally Posted by MattD

For all you guys that have lifted Titans, please remind your service manager that Nissan sells a lifted Titan. There is no possible way that a lift kit would have caused that additional strain.

If it tears again in the future and they refuse to replace it, I will surley bring that up. They have 4 brand new ones lifted on the lot with the full warranty right now.