SingleOwner

Thanks, @hawairish! This lift project has been quite a learning experience -- And it keeps going like the Energizer Bunny! Next up, angle finder and pinion angles. Might have to put it on pause for a bit while some other things are happening, but I'm looking forward to figuring this one out, too!

Thanks, @Slartibartfast! For peace of mind, I may just pick up some more fluid and have a look at the current gear oil. I changed it pretty recently so any chunky bits would be really noticeable. Not too expensive and I might sleep better with the knowledge that the diff isn't ripping itself to pieces. Thanks, @hawairish! Good to know that others have had similar noises/symptoms post-lift. The springs are definitely still settling, plus I only have ~100lbs extra weight in the back end (tools I usually carry around; no bumper, no spare carrier, etc.) so the settling process may take a little longer in my case than normal. If it is the u-joint, is there any adjustment or anything that can/should be done that would help alleviate the noise? (I think I know the answer to that since I'm guessing you would have done that and wouldn't still have the same noise.) Cheers!

Thanks, Startibartfast! I finally had time today to get the rig back up in the air and double-check things. Pulled the wheel off to look around and then re-attached -- No loose components (no spacers on this build) and no debris. I have to think that maybe my paranoia maybe mis-identified a little bit of rotation of the tire as vertical play.... After several trips at highway speeds I have used a laser thermometer to measure the temp of the rear diff just after parking: Never read anything higher than 145-150* F. (I'm just assuming here that abnormal operation in the diff would result in higher temps.) I've wondered about tire balance, etc., but the fact that easing up on the throttle (without reducing speed much) stops the sound makes me think you're right -- Perhaps the sound has been there for a while but the now-stiffer trailing arm connection transfers the noise more (prior arms were shot, now on my 3rd set in its 240k mile life). What's the average life span of a rear lsd differential in these anyway? Had the automatic transmission rebuilt last year, so maybe the diff has a similar life expectancy???

Hi there folks! First and foremost, thanks to everyone's inspiration and help here on the forum I recently lifted my 1999 Pathfinder SE (which I've owned since brand new in 1998). SYMPTOM: I recently started hearing a rumble/howl from the back of the rig at highway speeds above ~55mph, but only while on the accelerator. Lifting off of the pedal but without changing speed (cresting over the top of a hill, for instance), the sound immediately stops and then comes right back again when power is re-applied. TIMING: Lift was completed about 500 miles ago, but I really only first noticed this noise on the first highway trip AFTER installing all four new trailing arms 100 miles ago (torqued to spec with tires on ground). The sound is pretty noticeable so I'm probably about 85% sure that this noise didn't start immediately after the lift, but rather started immediately after the trailing arms. OTHER NOTES: - In front it's lifted with OME HD coils, KYB struts and Fleurys 1" spacers. In the rear it's got Land Rover 9449s and Bilstein 33185552s. - Manual hubs in front are unlocked and there is no accompanying vibration to speak of. - After lifting but before the trailing arms were changed, the ball joints, control arms and front stabilizer bushings were all changed. (Still need to change inner and out tie rods and rear stabilizer end links.) - Rear axle in air (in Neutral), front tires chocked, there is only a small amount of play when rotating driveshaft. - No thunking from the rear diff while driving (used to have this occasionally, but cured with a fluid change ~1,500 miles ago; proper LSD fluid used). - There is a little play in the rear passenger wheel/tire when I push back and forth on the 12 and 6 o'clock positions. (Bearings?) After a bunch of reading here, I'm thinking rear diff but why would new trailing arms introduce this? Could the lift have introduced this noise? Could the noise just be the rear wheel bearing and the timing of when I first noticed it (right after the trailing arms) be a coincidence? Your ideas and help are much appreciated!