sporadic vibration while driving

[oldhess]

1996 Pathy- I'm driving down the road and at certain speeds and RPM's the whole car shakes. It feels like you're driving down the shoulder on the highway with those little things meant to wake you up when you veer off the road, or on a washboard. It is brief never more than a couple seconds and is always at certain speed and RPM. It's not the tires, tie rods ball joint or alignment. only at a very specific speed and RPM.

[centralcoaster33]

Drive shafts? The long one going to the back tires... The carrier bearing could be all worn out. Do you have AWD? Maybe look at the transfer case where the shafts come out. I would look for an elliptical shape instead of a round one... and some fluid leaking maybe. I'd suspect you have some universal joints that are seizing up. They show their face most at certain RPMs. You can pull off parts and test them for motion. It's a bit tedious, but it's precise.

This is off the top of my head. I don't have a Pathfinder. But I have had to replace my driveshaft recently. Perhaps there is a common Pathfinder issue someone else may know about.

Good luck!

[baja98]

I have a 98 Pathfinder 2wd that does the same thing. Like you said, feels like driving over those wake up strips cut into the roads, just for a few seconds and then it goes back to normal.

[oldhess]

Drive shafts? The long one going to the back tires... The carrier bearing could be all worn out. Do you have AWD? Maybe look at the transfer case where the shafts come out. I would look for an elliptical shape instead of a round one... and some fluid leaking maybe. I'd suspect you have some universal joints that are seizing up. They show their face most at certain RPMs. You can pull off parts and test them for motion. It's a bit tedious, but it's precise.

This is off the top of my head. I don't have a Pathfinder. But I have had to replace my driveshaft recently. Perhaps there is a common Pathfinder issue someone else may know about.

Good luck!

I have 4WD and an LSD. I don't know if I was hoping for a common pathy problem or not. Since baja 98 has the same problem with 2WD sounds like could be a Nissan issue.
Baja what kind of Trans do you have? What speed/RPM is your vibration? Mine is right around 2000-2500 and 45-50 mph and again same RPM but 65-70 mph

[centralcoaster33]

Well, I hope Baja98 writes back. Combining what he said with my thinking, I would be most suspicious of the main drive shaft, the one that drives the rear differential. You can take that part off relatively easy, eight bolts I think on the shaft, two on a carrier bearing support. Get the thing in your hands. Try and move each universal joint. I suspect they will be stepped, click click click into various positions. Instead of having smooth sweeping motion through all angles. I'm not sure there will be a visual clue. Well, I can think of one. You drive around, upper speeds a while. If there's a bad joint, it will be getting hot from all the friction. Then you pull over and feel each joint to see if any feel hot. It's not as good as taking it off though.

[AlanAZ]

Probably a dumb question: have the 3 drive (prop) shafts (3 on 4wd, 1 on rwd) been greased on a regular basis? Or perhaps overfilled?

[baja98]

I've been watching lately and it does happen around 2000-2500rpm with 40-45mph. I don't know what transmission I have but the engine is the vg33e.

[baja98]

I have 135k miles on mine and no service has been done on the transmission or the axle since I bought it with 110k. I can feel it sometime going up hills when the transmission is deciding whether to shift to another gear or not. I will pay more attention, i live up a hill. I had a bushing/bearing replaced that the prop shaft went into. Not sure if they did all the u-joints when they put it back in. I will look at the work order and see what all they did and maybe remember if it was doing it before I had that work done.

[baja98]

I went and looked under the hood and the plate says I have a RE4R01A transmission.

[oldhess]

I was just looking for AT or Standard. Now I will have to look at mine. Alan not a dumb question unless you were assuming I hadn't in which case you would be right. I have driven the car a total of 40k I believe and have never greased anything. Guess I should get under there and look for some grease fittings. I was thinking it may be U joints but the specific RPM really makes me suspect of the transmission. I have dismantled every part imaginable on many different cars but I have never cracked a transmission. They scare me. I'll try greasing though I'm a bit skeptical.

[oldhess]

Well, I hope Baja98 writes back. Combining what he said with my thinking, I would be most suspicious of the main drive shaft, the one that drives the rear differential. You can take that part off relatively easy, eight bolts I think on the shaft, two on a carrier bearing support. Get the thing in your hands. Try and move each universal joint. I suspect they will be stepped, click click click into various positions. Instead of having smooth sweeping motion through all angles. I'm not sure there will be a visual clue. Well, I can think of one. You drive around, upper speeds a while. If there's a bad joint, it will be getting hot from all the friction. Then you pull over and feel each joint to see if any feel hot. It's not as good as taking it off though.

Why would this be the root of my problem if the problem is only at a specific speed and RPM? I thought the same but I convinced myself that the issue would be more prevalent rather than at specific points.

[AlanAZ]

Alan not a dumb question unless you were assuming I hadn't in which case you would be right. I have driven the car a total of 40k I believe and have never greased anything. Guess I should get under there and look for some grease fittings.

I've read since then that a slip-joint failure in a drive shaft causes a 'clunk' noise, and so not likely the cause of a vibration. However, after 40K mls, are due a couple of pumps of Moly grease.

[fleurys]

Just a thought... when you say it's not the tires...I assume you tried moving the front tires to the back and the back to the front ?

Also, in order to quickly rule out the front half-shafts and the front driveshaft, They can be removed without any ill effect on the truck. As long as you stay on 2wd on your road test. If the vibration is still there, it will go down less possible cause...

There is really no magic solution with vibrations like this... you have to go through elimination...

Good luck.

[centralcoaster33]

Why would this be the root of my problem if the problem is only at a specific speed and RPM? I thought the same but I convinced myself that the issue would be more prevalent rather than at specific points.

I honestly don't know the root of your problem and I thought the driveshaft could be it and is worth checking. My car seemed fine most of the time, but did exhibit some vibration and it was at certain speed and RPM, not all speeds or any RPMS on two different vehicles. I find it quit possible that a thing spinning can have more detectable vibrations at certain rotational speeds than it does at other speeds. Mine was the u-joints and it was extremely obvious they were bad when I pulled the driveshaft and held it in my hands. Likewise with my AWD vehicle. It had bad joints, but they were bad for so long, they'd ovalled out was used to be the round output from the aluminum transfer case. That area leaked around the seal.

I guess I'm just sharing some real world experience of two apparently similar situations I had in hopes that it would be helpful for you. You don't have to check anything I mentioned if you think it's not related. I'll just follow along and look forward to you fixing it and maybe sharing the solution. Best of luck!

[baja98]

Just to clarify, I don't think mine is coming from the axle or u-joints or tires. From what I've read, I think it has to do with when the computer tells the transmission to shift in order to get the best mpg. It only happens around 40-45mph but not every time and it feels like you are driving over rumble strips for about 1-2 seconds and then it goes away. If I put my foot into it when I take off it won't do it. If I take off slow and build up to 45mph it will do it, sometimes.

With all that, I am now trying a higher octane than the 87 I've been running. I'm going to run a couple tanks of 91 and see what it does.

[fleurys]

Just to clarify, I don't think mine is coming from the axle or u-joints or tires. From what I've read, I think it has to do with when the computer tells the transmission to shift in order to get the best mpg. It only happens around 40-45mph but not every time and it feels like you are driving over rumble strips for about 1-2 seconds and then it goes away. If I put my foot into it when I take off it won't do it. If I take off slow and build up to 45mph it will do it, sometimes.

With all that, I am now trying a higher octane than the 87 I've been running. I'm going to run a couple tanks of 91 and see what it does.

Yours looks more like a torque converter shudder... Higher octane in the gas will likely not change anything... Have a read at this article : http://www.agcoauto.com/content/news/p2_articleid/203 I would suggest an oil and filter change in the transmission. It is easy to do and you only have to drain via the drain plug.

S.

[baja98]

Thanks fleury, that was an informative read. I will change the filter and fluid and see. I've done a transmission fluid and filter change before on my old '77 Ford a couple times.

[fleurys]

Thanks fleury, that was an informative read. I will change the filter and fluid and see. I've done a transmission fluid and filter change before on my old '77 Ford a couple times.

If the problem goes away (or not), please update the post for everyone to benefit from it !
Cheers.

[centralcoaster33]

Your updated and reworded description pulls me away from the drivetrain thoughts. Fleurys seems to have a good cause to investigate.

[oldhess]

I have always been suspect of the transmission and a new filter has been on the list of things to try. I have the next couple days off. I'll give it a shot and see what I come up with as well.

[fleurys]

Also, I thing to remember is that around half of your transmission oil will still be in the torque converter when you will drain the transmission. So in order to fully change the oil in the trans, you might have to do it twice...but considering the price of a rebuilt transmission, I think it is much worth it... So I would drain the trans once, then drive for a week or so and then change it again, so you have as much new trans fluid in the trans that you can.

[oldhess]

So I changed out the trans fluid and filter and no more vibration. It runs at a lower RPM and I'm actually getting better MPG so hot damn I should have done this 6 months ago. Thanks for everybody's input!

[fleurys]

So I changed out the trans fluid and filter and no more vibration. It runs at a lower RPM and I'm actually getting better MPG so hot damn I should have done this 6 months ago. Thanks for everybody's input!

Thanks for updating the post... ! I'm Happy that it fixed your issue... I guess you were lucky on this one..

[1998Baja]

So I changed out the trans fluid and filter and no more vibration. It runs at a lower RPM and I'm actually getting better MPG so hot damn I should have done this 6 months ago. Thanks for everybody's input!

Thanks for updating the post... ! I'm Happy that it fixed your issue... I guess you were lucky on this one..

I lost my login, this is baja 98, and i also changed my transmission fluid and the problem stopped. Thanks fleurys