Chunky Posted July 22, 2013 Share Posted July 22, 2013 Hey guys! I'm hoping to get some advice. I've tried searching so I have a few ideas based on that research. Here's what happens... when I reverse it's fine. No noticeable sounds. When I move forward there seems to be a sound that comes from the rear passenger side. It's a soft of clicking, like a "dut-dut-dut-dut" sound. As I accelerate the sound gets faster, not louder. When I hit a certain speed, around 10-15 mph, it goes away.Now when I come off gas and I slow down, when I get to a certain speed slowing down the clicking sound comes back. It only seems to happen when going forward, the little time I spend going in reverse hasn't caused any weird sounds yet. Here's what I've checked so far... - I noticed that the 4 bolts holding the axle to the hub came loose. I tightened those. - I also read the possibility of u-joints. After tightening the bolts above, I grabbed the axle and gave it a good wiggle. It felt solid. I grabbed the diff-end of the axle and gave it a good shake. There was a little bit of play, a very very small amount. I figure that would be enough to be an issue. I checked the bolts between the axle and diff output shafts. I noticed that the wiggle seemed to almost be coming from the diff's output shaft, or the universal joint maybe? I thought I read somewhere that a tiny bit of slop is normal in these older diff's and that there is no slop when spinning.(http://www.zcar.com/forum/10-70-83-tech-discussion-forum/96436-wheel-differential-bearings.html) What's a good way to isolate the wiggle? a pry bar maybe to leverage the axle? I'm just trying to pinpoint the issue before I start "fixing things." I'd hate to spend time and $ on something that's not even an issue. Thanks guys! Ray Quote Link to comment Share on other sites More sharing options...
Chunky Posted July 22, 2013 Author Share Posted July 22, 2013 My bad I just realized that the link I posted was to another site. If this is a problem please let me know an I'll remove it. Doing more research I came across a post(on another site) where somebody mentioned changing diff fluid solved their problem, the issue was from the lack of fluid in the diff. Thinking about it now, I do recall seeing that the diff did have fluid all over it. Possible that it's low on fluid? I'll look into that next. Ray Quote Link to comment Share on other sites More sharing options...
Miles Posted July 22, 2013 Share Posted July 22, 2013 Make, model and year of car? List of any mods done to the car. Hard to diagnose without basic info. Quote Link to comment Share on other sites More sharing options...
Chunky Posted July 22, 2013 Author Share Posted July 22, 2013 Doh! Sorry, I was so focused on trying to be as descriptive as possible I left out the obvious. Its a 70 240z. Mostly stock as far as I know; r180, drums. It is lowered with springs in kyb inserts. Actually one other thing I noticed... The rear passenger side does sag compared to the other corners. I figured it was a blown shock bec I've heard kybs are not good with springs but they were cheaper. Quote Link to comment Share on other sites More sharing options...
BrandenZ Posted July 22, 2013 Share Posted July 22, 2013 JMort posted an amazing write-up on the various possibilities here: http://forums.hybridz.org/topic/105207-the-dreaded-diff-clunk/ For me, I solved this problem with the R/T mount: http://www.classiczcars.com/forums/engine-drivetrain-s30/35995-ron-tyler-differential-mount.html After a year or so of aggressively tracking the car, the clunking came back. That time it was an actual differential issue / preload / backlash issue. BTW -- Mine's also a 240z with an R180. Goodluck, hope it's a simple (and cheap) fix for ya! Quote Link to comment Share on other sites More sharing options...
Leon Posted July 22, 2013 Share Posted July 22, 2013 Do you also get vibration on the freeway? Sounds just like when I had a couple of loose driveshaft bolts. Quote Link to comment Share on other sites More sharing options...
Miles Posted July 22, 2013 Share Posted July 22, 2013 (edited) My 72 240z had a clicking sound coming from the drum brakes. The rate of clicking increased with the speed of the wheels. I pulled the drums to inspect the brake components (all new) and noticed that the shoes, retaining springs, springs connected to the shoes all "float" inside the drum. I figured that the if the shoes wore unevenly or if the drum was slightly out-of-round that could cause the internal parts to move as the drum rotated making clicking/scuffing sounds as the parts moved. Inspection showed that nothing was wrong. Later I swapped the drums for disk brakes and the clicking went away. The other clicking/scuffing sound that comes to mind is where the dust sheild on the flange that the half-shaft bolts to on the strut becomes bent and will rub on the outside of the stub axle housing as the shaft turns. The dust shield is thin metal and can become bent. This happened on my 240Z. I located where the dust shield was bent and lifted it away from the stub axle housing with a screw driver. No more scuffing noise. I have owned two 72 240 Zs with completely rebuilt rear suspension and drivetrain components. Both cars had R180 to R200 differential swaps. They both had a variety of noises coming from the rear at different times, but it never affected drivability. The differentials seem to be a common source of clunks. Just do a complete inspection of every bolt and component and renew as indicated. Clunking and other noises are a common complaint on Z cars and are well documented here and at other Z car websites. Recommend that you spend some significant time reading in the Drivetrain forums here and at Classic Z Cars website as there are several sources of noise comming from the back of the car. Also do a web search for "240Z clunk" or other such terms and you will see that there is a lot of data available on Z car rear noises. Edited July 22, 2013 by Miles Quote Link to comment Share on other sites More sharing options...
PLATA Posted July 22, 2013 Share Posted July 22, 2013 ^^^^ this is part of the love affair with these temperamental beauty's Quote Link to comment Share on other sites More sharing options...
280zex Posted July 22, 2013 Share Posted July 22, 2013 I had the same issue last night, I heard a strange clicking noise coming from the rear diff area. I assumed that a u-joint was on the way out. What I found was a loose drive shaft flange bolt to the rear diff. I read that you found the same, and fixed that, but the noise continues??? This may be an odd suggestion, however have you checked for debris inside the wheel center cap/hubcap?? I owned a auto repair shop and had a customer with a 4X4 with that same "clicking noise" from the rear of the vehicle. My guys checked it over well and found a small rock INSIDE the wheel center cap!!! Drove us bonkers!!! Quote Link to comment Share on other sites More sharing options...
Chunky Posted July 23, 2013 Author Share Posted July 23, 2013 Thanks for all the advice guys! My research continued after my posting. I did find some interesting things. I was able to spend some time today looking at it more today just before it got dark. I jacked the car up and took the wheel off. I checked the bolts that hold the half-shaft to the hub, they are all good and tight. With the wheel off, I was able to better inspect the half-shaft itself. I'm squatting in the wheel well looking straight at the half-shaft. When I grab it and pull it towards myself there's definitely some play. Pulling it towards myself makes a small clunk sound. I'm thinking that may be part of my problem but I want to hear from others that have experienced the same thing... that small amount of play and sound be an indication of something wrong with the shaft? Or am I convincing myself that that's the issue based on what I've read and it's normal? Off to more reading... thanks guys! Ray Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 23, 2013 Share Posted July 23, 2013 If this is an R200, the axle stub may have pulled part way out of the differential-it is only held in by an internal snap ring. Check to see if it inserted any less than the opposite side. A few taps with a drift and a hammer should re-seat it into the diff. If this diff has u-joints, try to see if a u-joint is moving when you pull in and out. If this axle is a CV axle, it is ok to have some play in the solid shaft between the CV joints-in fact, you must have some. Quote Link to comment Share on other sites More sharing options...
Leon Posted July 23, 2013 Share Posted July 23, 2013 Have you still not checked the driveshaft bolts? Quote Link to comment Share on other sites More sharing options...
Chunky Posted July 31, 2013 Author Share Posted July 31, 2013 Hey guys sorry about the delay. I've been slammed at work and don't have much time to really get in there since I (and the car) am moving in a few weeks. As a result I'm a little hesitant to start tearing too deeply into anything since the car will need to be moved shortly. Once I get the car over to it's new home I'll have no problems really tearing into it. Thanks for all the advice. I was able to get the car up and wheels off. I noticed that the passenger half-shaft does have a tiny amount of play when I yank on it, not rotational but pulling the half-shaft in and out motion from the diff. I also checked the bolts on the drive-shaft itself and they were all tight BUT I noticed that there is some rotational play. Pulling on it in and out it's solid, as well as wiggling it. However, I'm able to rotate it slightly both clockwise and counter clockwise. It's not a lot but it's enough to be noticeable. Is it normal for the drive-shaft(shaft between trans and diff, in case I have my names mixed up) to have some rotational play? I might have to check again, but it seemed that the rotation was not from the u-joint itself but from the input flange. Ray Quote Link to comment Share on other sites More sharing options...
Chunky Posted July 14, 2014 Author Share Posted July 14, 2014 Sorry about reviving this post from last year but I wanted to share the conclusion. I finally got around to going under the car. I started grabbing and shaking stuff. I found that my u joint on the drive shaft had a lot of play and shaking was making the clunk also the nuts had worked themselves loose which I'm sure didn't help any. I pulled it out and had a drive line shop replace the joints. This issue's been resolved. Thanks, Ray Quote Link to comment Share on other sites More sharing options...
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