Drivetrain Clunking...I'm going to need some help.

[HICKL]

For an R200, backlash should be between 0.0051 and 0.0071 inches.  Check with a dial indicator tangent to the ring gear.

 

 

Thanks Guys!

 

Hickl

[T-Bone028]

Jacob, did you ever get this resolved or did you ever track down the culprit to your clunk?

 

I'm going through the same thing right now...I've replaced EVERYTHING. Only thing left is the actual differential.

[jacob80]

No I have not, and I'm not sure what else to check! I may drop my rear end and drivetrain and have them inspected by a professional because at this point, I'm totally lost

[T-Bone028]

You and me both brother.

 

I know some other members chimed in and said they've had similar issues, and its been "ok", but just like you I'm worried about the "what if" factor. These cars seem to have a double-edged sword. So much joy, but so much stress.

[jacob80]

Exactly.

 

I know that any play is not good. I wish I just knew where to start! I want to say its normal, but I just don't think it is!

[FlatBlack]

I know some other members chimed in and said they've had similar issues, and its been "ok", but just like you I'm worried about the "what if" factor. These cars seem to have a double-edged sword. So much joy, but so much stress.

 

My car clunks, Trumpet's car clunks, Cygnus' car clunks. This is a common problem, and S30's don't just randomly 'blow up.'

 

I wouldn't/don't stress over it.

 

Here's a thread that has people chiming in about their drivetrain slop:

 

http://forums.hybridz.org/index.php?/topic/44745-differential-r200-rotational-play/page__p__705647__hl__drivetrain+play__fromsearch__1#entry705647

Edited July 21, 2010 by FlatBlack

[jacob80]

I don't like it though, normal or not. I think any kind of movement/play in these parts will (over time) create problems faster than if there was no play. Grrr!

[Miles]

I may have missed it, but have you guys checked for slop between the stub axle flange and the stub axle? On my stock 240Z the passenger's side flange splines had become worn and sloppy. I replaced the flange and the "loose flange" noise went away.Also, check the torque on the stub axle bolt. I have had both problems.

 

On this same stock 240Z the passenger side stub axle broke at the flange and the car contiued to clunk as I drove home the same as before it broke. The stub axle broke making a normal tak- off from a stop sign making a noise like the car had been hit hard. I replaced both stub axles with new OEM parts. The clunk has never gone away.

 

I had clunks in my stock 240Z and replaced every component new (swapped in1978 3.54 R200) in the rear and still had a clunk.

 

I just finished a 350 SBC swap with a t5 and r200 in my stock 240z. I replaced all of the bushings and front diff mount with a solid mount and it still clunks.

 

My first 240Z v8/T5/R200 swap for my son was the same story-complete new drive train including a R200 with solid front diff mount and all bushings replaced and it clunked on the passenger side. He drove the car hard for four years and nothing ever broke.

 

My clunk always seems to be on the passenger's side. I don't worry about it anymore after 12 years of stock and hybrid 240Zs clunking. I just shift smooth. I have a stoage shed full of R180s, R200s and side shafts that I changed out chasing the clunk. I have had Nissan mechanics, Japanese car mechanics and race car mechanics diagnose the clunk.

 

From what I have read, new 240Zs clunked.

 

Personally I would like to see at least three Z owners who have actually solved the clunk problem to speak up and document exactly how they diagnosed and solved the problem.

 

Perhaps it is just the stack up of all of the tolerences in the differential.

 

 

Miles

Edited July 22, 2010 by Miles

[randy 77zt]

i have had this problem before and now its back.what i found was wear bewteen the diff case and the back of the spider gears.you can see the flange for the axle shafts move up and down a little too.i usually get this after a replace a r200 after about 2 years.i think its from having too much fun with the car.if you have the r200 on the bench with the cover off ,axle flanges in and hold 1 axle flange and rotate the other you will see the spider and side gears moving around ,problem is my current r200 is a clutch type oem 300zx unit and i am sad its pretty much junk now.going back to a 280z 3.55 open unit.

[T-Bone028]

While I understand the inherent nature of a +35 year old car (it will groan, clunk, squeek, etc), I cant help but strive to get it to as close as possible to perfect (or at least my interpretation of perfect). Thats why we all do this right?

 

Seeing as this is pretty documented as a common problem (Thank you FlatBlack for the link), I will do what I can to minimize or mask it. I have a R/T mount on the way and hopefully pairing it with a poly mount instead of my current solid mount will help quiet things down.

[dizzle]

On your R/t mount are you using the rubber or poly bushing? I read that the rubber bush can break on the first drive. And have you put a couple of washers inbetween the diff and the mount? I just went through a "hunt for clunk" and that is what it turned out to be. The poly mount was just squished to the diff, and did not have a solid mounting surface(with the diff having the hump in the middle between the mounting holes). I added 2 washers under the mount, made sure everything is tight and no more clunk.

[T-Bone028]

I havent received the RT mount yet, its still in production for the group buy over on ClassicZcars. I might opt for the GM poly mount, or try the poly bump stop method paired with a stock rubber mount to "sandwich" the diff. Thanks for the heads up on the washers. I'm pretty sure the RT mount wont solve my thunk, but at least I will have less of a chance of cracking my cross-member as a result of my solid diff mount like others have experienced.

[jacob80]

On your R/t mount are you using the rubber or poly bushing? I read that the rubber bush can break on the first drive. And have you put a couple of washers inbetween the diff and the mount? I just went through a "hunt for clunk" and that is what it turned out to be. The poly mount was just squished to the diff, and did not have a solid mounting surface(with the diff having the hump in the middle between the mounting holes). I added 2 washers under the mount, made sure everything is tight and no more clunk.

 

I have the R/T mount and I STILL get the clunk. I'm using the energy suspension bushing, I would assume its poly (red). I have also replaced ALL bushings all around. perhaps I need to take your advice with this washers thing. I may need to draw up a digram to interpret what you mean, but perhaps that is my problem.

 

The bummer about this whole thing is that I had the EXACT same sound as I did before installing the R/T mount. I've put a new rear end in, all new energy suspension bushing, 280z 27 spline stub axles and 300zx turbo CV shafts, and the R/t differential mount. Grr...

[T-Bone028]

So I was thinking about the purpose of the R/T mount, and its original inspiration. Its supposed to replace the weak stock rubber mount and improves upon the design, which I understand. Its also supposed to allow the differential to be slightly lower, which supposedly helps with V8 type applications and helps to straighten out driveline angles.

 

In a L6 application, does the lowered position of the differential have any averse effects such as greater u-joint wear from the increased driveline angle? Opinions welcomed...sorry to hijack Jacob!

 

And, I dont suspect I'll ever get rid of this clunk short of replacing or rebuilding my diff...not something I want to do since I already have a R200 LSD! My only hopes is that switching from a solid mount to a poly will help muffle the clunk and add some dampening effect over my current solid diff mount. I'm going to go ahead and cross my fingers in hopes that it will help extend the life of my diff in some magical way...or I'll find a way to get Mr. K to bless my car. He already signed my glovebox and it hasnt broke yet, maybe he can sign my diff.

[jacob80]

Okay guys, I have some news.

 

I took a video of my rear end with my car up on jack stands. Here it is:

 

 

It looks like my rear cover is not secured tight enough to my mustache bar. My question is, do YOU think its wiggling around too much? I need to drop the rear end anyways to inspect it, change the cover gasket, and figure out why my rear cover isn't staying snug to the mustache bar. Let me know what you guys think. Perhaps this could be the cause of my clunk noise after all!

 

Thanks!

[jacob80]

Hey guys,

 

Well, I return with bad news. I inspected everything and the clunk is STILL there

 

I completely tore my rear suspension off, cleaned everything up, made sure everything was torqued correctly, but no luck

 

I also discovered that I have a bad Illumina strut due to a loose gland nut. I tightened down the gland nut and kept the strut in there for the time being ($), but I don't think that would be the problem.

 

It sounds like the clunking is coming from there rear, but I'm not 100% sure. I wish I could mount a camera to the bottom of the car or somehow reproduce the condition in a controlled environment, any ideas?

 

I'm trying to get read for the Midwest Z Fest and I can't seem to figure this one out! Dahhh!!

Edited August 19, 2010 by jacob80

[JMortensen]

Loose gland nut will make a hellacious clunk.

[jacob80]

I tightened the gland nut, but the clunk is still there.

 

Honestly, I'm not sure what to try next. I could replace the saggy strut, but I'm sure thats not causing a clunking sound.

 

I can always get it to do it. Say I'm just crusing on the highway; if I just goose the throttle and buck the car just a tad, it'll clunk for every "goose" that I initiate. Ughhhhhh this is BUGGING me!

[cygnusx1]

Sounds like my car.  I just learned to drive it smoothly.  Rev match, heel and toe, smooth throttle and clutch movements.  My passengers never hear the clunk, unless I let them drive.  Then they say WTF was that! I blame it on their driving skills. 

[jacob80]

Drove it again last night and I would say it would take some skill to cover up the clunking noise.

 

I just went ahead and ordered a new transmission mount, HOPEFULLY this is the culprit. This piece has not been replaced ever, so maybe its just worn/cracked and causing the transmission to bang up against the body.

 

The rear end is SOLID. I made sure of this by using two nuts to fasten the differntial cover to the mustache bar and tightened it to spec, and I am also using a Ron Tyler front differntial mount, and it trule is solid.

 

This condition is only happening when power/torque is transferred to the wheels, so something is still loose. Would there be any way that the stub axle could cause this noise? Or perhaps something in the wheel/hub assembly?