Davus

Thanks for the in depth reply mate. Much appreciated. I actually did the sump gasket on the car yesterday, and as part of that i needed to lift the engine slightly, which gave me a chance to look at the mounts. Whilst they clearly arent new, they not looking too bad really. But in reality, given that ive removed the shaft and been able to eliminate the vibration, i think im leaning very heavily towards something in the rear of the drivetrain. Transmission mount is obviously very easy to change, so i might order one and just do that anyway. I've also noticed a bit of a "squeak" when i go over a speed bump coming from the rear, which almost speaks to trailing arms. I might have a look at those bushes. The guy who balanced the driveshaft did say it had a mild warp to it, which he fixed. Im making an assumption he also checked the runout (thanks for explaining that). Ill test it thought with my dial indicator, but im now suspecting anything out of the ordinary there. Logically in my mind im having trouble not suspecting the rear diff. By process of elimination, it seems to be the next logical place to target. The driveshaft is recessed well into the transmission housing. It sits in most of the way.

Hi Mate, Thanks for replying. Clearly you're a troubleshooter So, a couple of questions and comments. 1) I haven't specifically checked the mounts for either the gearbox or the engine. TO be honest, given i took it for a spin without the rear tailshaft in (with no vibration), i didn't really consider them. Do you disagree?. 2) Excellent question! - I was wondering if someone would pick up on that, and it intrigues me that you have. You have clearly taken the time to read through all the testing and troubleshooting i have dine, which i thank you for. Please treat this as innovative, rather than bad practice :). I removed the shaft, and placed a double layered thick plastic cover over the end of the transfer case. I knew that this would still mean fluid exited from the rear seal, but given it couldn't really go anywhere, and i was only driving for around 5-8 minutes, figured it would be fine. When i got home, i cut the plastic, and collected the fluid that had been caught. I discarded it in-case it had contaminants in it and refilled the transfer case as required. Innovative ...... yes? 3) Im not sure what you mean by runout. Can you explain a little more? Sorry - As i said, I'm still a little new to tailshaft physics / mathematics. I assumed that given the shop had balanced it and checked it over fully, it should be OK to simply re-install. Am i wrong in that assumption? 4) Thats a good idea. I will get my wife to drive the car, while i observe her from behind. :P

Good question - I did not check the pinion bearing in the diff. To be honest im learning more about this as i go, so id have to remove the rear driveshaft to check that again. As luck would have it, it's up on a mates hoist at the moment, so ill do that tomorrow. I believe the "phasing" of the shaft is good. Again, I don't fully understand it, but i believe it's the same correct orientation as your picture. Here is a pic of my tailshaft before installation. To be honest, i dont really understand how it would ever be incorrect. I wouldnt be able to phase it incorrectly if i wanted to????

Hi All, SO ive been continuing to work through this issue, and wanted to post a summary with a little extra info, and get as many ideas as i can. Here is what i know so far. 1) The vibration occurs around 75km/h, and is very evident through to about 95km/h. After that it is still there, but it reduces significantly, almost to the point a "regular"passenger wouldnt realise. 2) The vibration is a very fine type vibration that comes through the floor / seat. It is not through the steering wheel. 3) If i roll downhill at the speed in question and click the car into neutral, it still vibrates. In addition to this, the vibration does not align at all with engine revs. This eliminates engine. 4) There is no difference when i apply the brakes, therefore i have eliminated brakes / rotors. 5) I removed the front driveshaft from the transfer case to the front diff, and had no change in behaviour. Vibration still there. Therefore I have eliminated front drivetrain. 6) I have changed to a second set of wheels, and even rotated them (and had them balanced). This made zero change to the vibration. Therefore I have eliminated it being wheels / tyres. 7) I removed the rear tailshaft, effectively turning the car into a Front Wheel Drive, and went for a very careful drive up to the speed in question. I was extremely on edge (given i didnt want to put too much strain on the front (thin) shaft, but couldnt feel any vibration in this configuration, leading me to think it must be something to do with the driveline from the transmission back. I changed both uni joints in the rear tailshaft (its a one piece), and have had the tailshaft professionally balanced. Unfortunately didnt make any difference. Therefore, I have elliminated the tailshaft. 9) I purchased and installed an app called NVH (at the handsome price of $150 AUD), on my iphone which pointed the finger at an engine vibration. Clearly wrong given i have already eliminated it being an engine vibration. 10) I jacked up the rear of the car, places it in gear and slowly accelerated up to 75km/h. Vibration clearly there. (really just confirming other tests). While the car was up in the air i checked for wheel trueness, which all looked fine. For reference at the moment the car has standard wheels and tyres on it. So that's where i'm up to. I am now at a bit of a loss, and really starting to think outside the box The car does have a 2 inch lift kit in it. Some research seems to indicate that the uni joint working angles in the main rear tailshaft may be an issue because of the lift kit. Ive taken some angel measurements, and calculated that the front Uni joint at running at around 5.2degrees, while the rear uni joint is running at around 4.5 degrees. Google seems to indicate that 2 degrees is much more acceptable, and that the angles I have are a high potential for causing the vibration. The suggested fix is adjustable rear trailing arms. Outside of that, i would have to assume its something in the rear diff. I would not suspect the axles in the rear diff housing at this stage for two reasons. 1) They ran true when i had the car up in the air. 2) When i ttok the tailshaft off and drive it, if it were the axles, the vibration still would have been there. So - What do folks think?. Im depserate here, so hoping to hear any and all ideas. EDIT: Sorry i should also add that the vibration itself is more of a "cyclic" / "harmonic oscillation" type vibration. SOme online reading seems to support the uni joint working angles with this type of vibration. Thankyou!

True - Its very difficult to narrow down without using the "process of elimination" approach and just replacing things until the vibration goes away. I did come across an iphone app called NVH wich is a vibration diagnosis app, and claims to be outstanding for diagnosing this type of thing. It also has a few solid reviews on YouTube, however its $150,and for an app that seems like a lot to pay.

Hi all. I realized I forgot to drop into this forum and say hello! We’re from Australia, and my son (17) has just bought his first car. It’s a 2000 Nissan pathfinder r50. Aits got quite a few km’s on it (300,000 km), however has only had one owner, and has full service history!. we’re looking forward to working on it together, and will no doubt have a lot of questions for the group. Cheers!

Thankyou mate. I pulled the transmission, and unfortunately found that the leak is actually coming from the rear seal of the sump, and not the rear main. I changed the rear main while I was there anyway, and have temporarily sealed the oil leak with some RTV. In the next month or so I guess I’ll need to either pull the engine out, or drop the sub frame to get the sump out and change the gaskets. Thanks!

Hi all. Thought I would post here first, before diving any deeper into a problem I have. The car is a 2000 pathfinder with a touch over 300,000 km on the clock. We’ve only owned the car for a month or so and are workin through that various bits and pieces for road worthy. My son (17) bought it as his first car. It is otherwise a great car, and has been looked after well by its one owner since new. It has a notable high speed vibration that comes in at around 80 km/h, and then goes away at about 95 km/h. It’s not a front end vibration, and cannot be felt through the steering at all. This presents as a low frequency “humming” vibration felt through the seat / floor of the car. Wheels (stock pathfinder wheels) have been balanced, and both uni joints on the main driveshaft have been replaced. I have removed the front driveshaft to eliminate anything front end…..and can confirm that there was no change in behavior. I also fitted up a second hand driveshaft I got from a wrecker, which didn’t change the behavior at all either. Before I start digging deeper (diff / bent axles etc), I thought I would just post a query to ask if there’s anything specific to these vehicles that I might want to look for. Do they have a tendency to fail in any particular area that might be causing this issue? Also open to any other ideas. Thanks all.

Hello from Australia folks!. MY son (17 years old), has just bought his first car, in preparation for his 18th Birthday (when he is legally allowed to drive by himself) - Yes, Australian rules We pick the car up later today! There are a couple of items we need to do quickly to get the car on the road, one of which is the rear main seal. I've read a few posts on this forum (and others), which seem to indicate that oil pan needs to be dropped, which means the subframe needs to be dropped. However when reading these forums, Ive noticed that they mostly seem to be talking about American builds, which run the 3.5L VQ35DE V6, whereas the Australian release runs the 3.3L VG33E engine. I think this may be more related to the year rather than the release country? My question is, has anybody got experience in changing the rear main seal on the VG33E 3.3L engine?. Is it as involved as the 3.5L variant?. Link to any possible how-to's would be greatly appreciated. I've not been able to find anyhting relevant. Thankyou!