pathfounder Posted March 14, 2012 Share Posted March 14, 2012 It's actually possible for the ignition system to cause vibrations, which would be worse under load. The RPM test 5523Pathfinder suggested would help with this, but hold the same vehicle speed and change gears (so the opposite basically). If the vibration changes, it's a problem with the engine, possibly ignition. I chased a problem like this and it turned out to be a bad distributor cap. It obviously doesn't apply to the VQ, but there could be a similar problem. Link to comment Share on other sites More sharing options...
Towncivilian Posted March 14, 2012 Share Posted March 14, 2012 (edited) Yeah, how many kilometers do you have on your QX4? 169k km is the spark plug replacement interval. Transmission fluid at the proper level when hot, clear and red, smells fine too? Edited March 14, 2012 by Towncivilian Link to comment Share on other sites More sharing options...
kdj Posted March 15, 2012 Share Posted March 15, 2012 (edited) Actually I suggested the RPM check. If the vibration happens at the same RPM regardless of which gear the tranny is in, it is NOT the driveshaft. If the vibration decreases or stops when the tranny is in a different gear at the at the same RPM then it IS the driveshaft, u-joint(s), centre hanger or even the tranny yoke. I don't think I got anything backwards. It still sounds like a bad u-joint to me or maybe the driveshaft counter weights got knocked off-it is a low rider! Either way it will show if that's the problem or something else like tires, brakes, distributor cap, anti freeze etc. If you haven't change u-joints before you might be better off having someone else do them...just make sure to make marks on the driveshaft flange and pinion flange in line with each other before you remove it so it's installed in it's original position. Edited March 15, 2012 by kdj Link to comment Share on other sites More sharing options...
WOT Posted March 15, 2012 Author Share Posted March 15, 2012 Im going to tie my camera under the car in the morning and tape this noise, it has got to be identifiable by an experienced hand just by the noise itself. I will also do the RPM test Spark plugs were changed when I got it with the proper NGK's, tranny fluid was mint a week ago when I changed my engine oil. I have traffic court early in the morning, so Ill have the video up early, Ill probably just pull the driveshaft while I wait for some replies though (and Ill line mark everything so it can be installed the same) Thanks guys Link to comment Share on other sites More sharing options...
Slartibartfast Posted March 15, 2012 Share Posted March 15, 2012 ... so you put it on a jack stand, only one wheel spun easily, and the other one had a really hot brake drum? It may not be your only problem, but I think you've got a sticking brake. Link to comment Share on other sites More sharing options...
WOT Posted March 15, 2012 Author Share Posted March 15, 2012 (edited) Not like that. The brake passenger brake drum was hotter than the drivers side after a 20 min drive On stands with the car in D, the drivers side spins first, but if you slow the drivers side tire with your hand, the passenger starts spinning then. They both spin easily in neutral Im going to make that video this very second I hope the noise is audible while driving Edited March 15, 2012 by WOT Link to comment Share on other sites More sharing options...
WOT Posted March 15, 2012 Author Share Posted March 15, 2012 Here is a video I made tying the camera under the car. Probably to shaky to watch, but the audio is kinda good. I started off just rolling, then drove @ 20mph I also did the gear changing test. The noise is MOST pronounced while in 1st gear, then as you shift into second it got weaker, and when I put it in drive, it sounded like it does in the video. I dont have any clear roads with straight stretches here in the city though. Hope the video helps, Ive got a 12 hour shift then I hope to resolve this problem Link to comment Share on other sites More sharing options...
WOT Posted March 15, 2012 Author Share Posted March 15, 2012 (edited) Damn that video sucks eh. I was able to recreate the noise while the car was on stands, not as bad as I think it is while driving. But atleast I got a video of the noise. Its DEFINETELY coming from the very back of the driveshaft. This area And this is a video of the noise coming from that area with the car in drive on stands, hope its audible, I can hear it if I turn the volume up a little So Im thinking it is actually related to that play at the very back of the shaft like I thought. Or is there a bearing or something in the case of the rear end? Is it worth it to pull the back half of the driveshaft off by unbolting it from these two areas? Is that ok? Maybe I would see something.... What do you guys think?? Edited March 15, 2012 by WOT Link to comment Share on other sites More sharing options...
pathfounder Posted March 15, 2012 Share Posted March 15, 2012 The pinion has a bearing right up front, a bit behind the dust cover. I can't really tell by the video, but I think I hear bearings. If it's the worst in first and gets better with each up shift, then that may mean it is torque related, which makes some sense. The torque in the drive shaft is over 750 ft-lb in first gear. Diffs are replaceable. I have one kicking around. Link to comment Share on other sites More sharing options...
WOT Posted March 16, 2012 Author Share Posted March 16, 2012 Only 6 people watched my video?? Shart I was hoping for a million hits lmao Link to comment Share on other sites More sharing options...
JamesRich Posted March 16, 2012 Share Posted March 16, 2012 You are talking about that random knocking noise? That couldn't be a bearing. You don't have u joints, It looks like a type of CV joint. I had never seen that on the rear shaft. You should pull the shaft and rotate them around feeling for binding. The FSM calls that a birfield joint and just says do not disassemble. You probably have to replace the whole shaft when they go bad. When on stands can you feel the random noise coming from anything? James Link to comment Share on other sites More sharing options...
pathfounder Posted March 16, 2012 Share Posted March 16, 2012 You are talking about that random knocking noise? That couldn't be a bearing. The knocking sound is definitely something unrelated. What I was noticing does sound like bearings, like the sound you hear with a worn transmission or something. It's very hard to tell though. Link to comment Share on other sites More sharing options...
kdj Posted March 16, 2012 Share Posted March 16, 2012 Only 6 people watched my video?? Shart I was hoping for a million hits lmao Link to comment Share on other sites More sharing options...
WOT Posted March 16, 2012 Author Share Posted March 16, 2012 Tranny was rebuilt 18 months ago. Hope it has nothing to do with that. I definetely think it is something at the VERY rear end of the shaft, either that play in the shaft, or maybe there is a bearing right at the front of the case where the driveshaft enters it? I cant "feel" it coming from anything when its all spinning and my head is a foot away lol, but the noise was definetely was coming from this area. Im unsure of all what could be inside this area. Am I allowed to take the driveshaft apart in 2 pieces, like in the pic I posted above where I red squared the 2 bolting points. It seems this driveshaft is 2 pieces... Link to comment Share on other sites More sharing options...
kdj Posted March 16, 2012 Share Posted March 16, 2012 I thought the video was great but I'm on dial up so it takes about 10 minutes to watch it. It was better than alot of what's on TV! Completly different set up than my u-joints. Link to comment Share on other sites More sharing options...
WOT Posted March 16, 2012 Author Share Posted March 16, 2012 IS it important to mention that this is a florida, USA 2wd?? I brought her to canada Eh Link to comment Share on other sites More sharing options...
JamesRich Posted March 17, 2012 Share Posted March 17, 2012 Im unsure of all what could be inside this area. Am I allowed to take the driveshaft apart in 2 pieces, like in the pic I posted above where I red squared the 2 bolting points. It seems this driveshaft is 2 pieces... Here is the pic from the FSM. What you red squared is the differential yoke where you need to disconnect it. It looks like an identical flange at the center support bearing, looks like six bolts on each side. You need to make sure that the drive shaft has enough compressed length since you lowered the truck. I saw in a pic you posted of your short springs it looks like you removed the bump stops too. If the drive shaft slip yoke is bottoming out and pressing against the differential when the suspension is fully compressed it could screw up the bearing in the front of the differential. I have seen this happen on a buddies 65 impala low rider. James Link to comment Share on other sites More sharing options...
pathfounder Posted March 17, 2012 Share Posted March 17, 2012 JamesRich makes a good point. You may need the driveshaft shortened ($150). Link to comment Share on other sites More sharing options...
WOT Posted March 17, 2012 Author Share Posted March 17, 2012 Well last night I took the Qx4 on the highway for the first time in a while (probably since this started) and on the way home it developed a WICKED vibration/bounce from the rear end during low speed braking. When I got home I touched both back drums and noticed the passenger rear was wayyy to hot. So ofcourse I slept in today, but when I took off the drum. Check what I found.... Ya, shoe wasnt even attached to the wheel cylinder... Those pads are pretty shot from being run like that, and the drum has some good grooves, and I pulled the drivers side off and everything looks pretty good over there. But since I live in a small town there are no places open to turn my drums. So I just bought everything new, might aswell do both sides obviously. Was pretty surprised they had everything in stock . Wasnt to bad, only $220 for new drums, shoes, hardware and 3 cans of brake clean Link to comment Share on other sites More sharing options...
WOT Posted March 17, 2012 Author Share Posted March 17, 2012 So I may still have a problem with my driveshaft, but this problem superseeds that for the day lol. These springs dont looks to forgiving!! Link to comment Share on other sites More sharing options...
JamesRich Posted March 17, 2012 Share Posted March 17, 2012 It looks like the hold down pin on the left side was broken and not holding the shoe very well but it came off the wheel cylinder when you were pulling the drum off. If the shoe would have been off of the wheel cylinder while braking the wheel cylinder would have come apart. The shoe was probably dragging and causing the over heating issue so you should have fixed that problem. James Link to comment Share on other sites More sharing options...
WOT Posted March 18, 2012 Author Share Posted March 18, 2012 Yeah the passenger side was in poor condition, when I first inspected it, there was no boot coverring the star wheel adjuster hole, and I think you are right about the shoe hold down pin breaking and letting the shoe go free and causing that damage. Link to comment Share on other sites More sharing options...
kdj Posted March 24, 2012 Share Posted March 24, 2012 So was it your drive shaft or brakes? I still liked your under truck video. Link to comment Share on other sites More sharing options...
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