Thunk or Poping noise coming from rear end

[flip]

I've found out a lot about the poping noises and such that I've been having so I thought I'd document my findings. The noises aren't all the way gone but are about 75% better now with the newly welded diff.

Theres more than one thing that can cause the poping and clunking. 1) The Diff - It's most likely this. I find that when you are kinda hard on these diffs they tend to gather a little bit of play and make quite a bit of noise.
2) The Subframe Bushings - If your bushings are worn out and torn the subframe will knock on the frame.
3) The Axles - With my axles I noticed that when I turn the driveshaft manually the portion of the driveshaft closest to the diff moves slightly but the portion connected to the hub does not. That means there is some play.


In my case getting my diff welded (was an open diff) tightened it up enough to eliminate most of the noises from my rear end.


The diff's in our cars tend to loosten up after time. You can fix this by finding out the stock tolerances, measuring the tolerances on your diff and getting the correct shim's to eliminate any play in the gears.

[flip]

I'm going to continue to try to remove all of the play from my divetrain after I get my new coilovers and finish installing the master bushing kit I have. I want to eliminate those two possibilities first.

Also my alignment is screwed so that could be putting some unnecessary stress on suspension members creating noises that wouldn't normally be there...

[flip]

Alright. I have replaced every bushing and mount on the car and the clunk noises have come back over the past few days... It sounds like its coming from the diff and you only really hear it when turning sharp turns. I do expect to hear noise from the welded diff, but mostly just tire chirp. I've ridden in a 240 with a welded diff before and all it had was the tire chirp noise. Mine has a good bit of clunking.

Has anyone had experience with this before?

[flip]

Thought I would add that a few people suggested looking at the center bearing on the drive shaft... Since it's gotten better then worse again after I welded the diff I don't think this is it but just thought I'd throw it out there. I'm gonna try to put my car up on the lift today and see whats goin on...

[babowc]

werd..
i know mine is clunking bc of a brken stud ont he subframe..

[ahmonrah]

i've got the same thunk issue but it sounds as if it's coming from the front left area.i've got to find out what the issue is.

but also, the bearings in the right front hub are going bad. resulting in vibration between 45-55mph settling down just past the 55mph mark. but alas!

solution:
hit pull-a-parts(norcross/moreland ave), dropkick the first vulture eye-ing an S13.

if that S13 is bare...apologize to the guy and run to the next 240sx on the printout list, preparing for battle...

continue looking/dropkicking til the hub i'm looking for is located, grab it and run, 'cause now i've pissed off and injured alot of people in my quest for no vibration. pay and sprint to the car, 'cause they've told the cops of my abuse.

[Casey]

hahah
where is this junk yard?
+1 lmao


i've got the same thunk issue but it sounds as if it's coming from the front left area.i've got to find out what the issue is.

but also, the bearings in the right front hub are going bad. resulting in vibration between 45-55mph settling down just past the 55mph mark. but alas!

solution:
hit pull-a-parts(norcross/moreland ave), dropkick the first vulture eye-ing an S13.

if that S13 is bare...apologize to the guy and run to the next 240sx on the printout list, preparing for battle...

continue looking/dropkicking til the hub i'm looking for is located, grab it and run, 'cause now i've pissed off and injured alot of people in my quest for no vibration. pay and sprint to the car, 'cause they've told the cops of my abuse.

[NcTurnL]

my S13 was clunking to, but only when I was in reverse and coming to a stop, I changed the rear brakes and it solved my problem..weird..

[v-empire]

[QUOTE=ahmonrah;12665]...but also, the bearings in the right front hub are going bad. resulting in vibration between 45-55mph settling down just past the 55mph mark. but alas!

QUOTE]



i would assume your wheel and tire needs to be re balance if its doing that / or replaced. bad hubs are normally very whinny when driven during load and of load its quite. or.....i could be wrong, just experience.

between a set pace/range for wheel vibration is a sign of bad wheel balance. try swapping a wheel out of swithing them before looking further. hope it helps. let us know the results.

[ahmonrah]

that's cool v-empire, 'cause i have a set of new tires on my legend that are the same size and have never been driven on. i bought them and a week later my clutch shit on me. for a years it's been sitting. i'll swap them on and see what's good.


so what about the "clunk"? i'll check with RB when i seen him. hopefully friday.

[ahmonrah]

hahah
where is this junk yard?
+1 lmaogo here........ http://www.pullapart.com/

[deez_lug_nutz]

The clunk your hearing is the diff itself! U cant run a welded diff if a street car. during slow sharp turns the inside wheel has to spin less revolutions than the outside wheel. thats y when u rebuild a clutch type lsd like a kaaz diff u can put the clutch plates in a certain order to give a certain % of locking. If you build it with 100% locked the inside wheel will hop and skip trying to catch up to the outside wheel.
My suggestion would b to get a vlsd or a open diff and the popping would go away!

[flip]

The clunk your hearing is the diff itself! U cant run a welded diff if a street car. during slow sharp turns the inside wheel has to spin less revolutions than the outside wheel. thats y when u rebuild a clutch type lsd like a kaaz diff u can put the clutch plates in a certain order to give a certain % of locking. If you build it with 100% locked the inside wheel will hop and skip trying to catch up to the outside wheel.
My suggestion would b to get a vlsd or a open diff and the popping would go away!

I wouldn't consider it a street car since it isn't really daily driven... I expect it to chirp and make some noise but not all the noise that mine is making. I've pretty much come to the conclusion that it needs to be re-shimmed since it's so old and the shims couldn't take the beating from a welded diff.

I did mention earlier that the vlsd also made the poping noises after a while which I believe to be the same thing. Shims. I am about to pull that VLSD appart this weekend and find out. I'll be taking measurements of clearances to see what we're lookin at.

[mo_jo]

my S13 was clunking to, but only when I was in reverse and coming to a stop, I changed the rear brakes and it solved my problem..weird..

Common problem, the pads are sticking on the pins and rolling the car backwards pops them out causing the noise. This is why it's neccesary to lubricate the pins when installing pads. This normally only happens in reverse, or when the wheels switch directions. Use brake and caliper grease on the pins.

[babowc]

hm.
flip mind to update this if you have fixeed it?
I went to look at a car yesterday..
the car was literally thudding and shaking from the rear.

anything over 20 was like that..
gonna go back tonight to check it out more indepth, but what was the reason on yours?