Chevy SSR Forum banner

1 - 20 of 25 Posts

·
Registered
Joined
·
1,502 Posts
Discussion Starter #1 (Edited)
I noticed that after the first real hot day here in the NW, and the black SSR setting in the sun all day, I didn't here any tinks or that rattle I've been hunting.

It rained today, and THEY ARE BAAAAACK!

Your ride sounds like a hoot and a half.

Skip
You know, I'd noticed the tinks had died back yesterday and today, didn't connect it with increased temps. It's actually been quite nice the last two days.

Ok, So heat means parts are expanding, some parts expand more than others.
alum 24 x 10 -6 in/in/deg
steel 12 x 10 -6 in/in/deg

So, the drive line is ~54" and and given a temperature shift of 30 deg:
Then the drive line will grow by 54*24*.00001*30= .388 inches
While the steel truck grows by half that much or .194 inches

That's a little more than 3/16 of and inch difference. More than I expected.

The question becomes, How does 30 deg. temp swing and a 3/16 inch difference in length make the tink go away?

Edit:
another source says that the coefficients are
12.3 x 10 -6 in/in/deg for alum
7.3 x 10 -6 in/in/deg for steel
 

·
Premium Member
Joined
·
2,175 Posts
Good question. I will pose your hypothesis to my phd. avionics engineer buddy who designs heliocopters. He thinks he's smartier than me, a lowly chemist. He drives a black Miata, but keeps a 200,000 mile old chevy pick-up as a spare ride.
 

·
Resident Rocket Scientist
Joined
·
11,997 Posts
Since the drive shaft is allowed to 'float' (in and out) at the yoke on the transmission end the relative change in length would mean the yoke is into the transmission a little more.
Maybe more contact on the splines of the yoke to trans?? (Doubtful)
Since I've never heard the tink I don't have any more ideas for now.. :confused
 

·
Premium Member
Joined
·
2,175 Posts
Maybe the difference in length is not the issue. What about the drive shaft radius? Since small weight deviations cause major tire balance problems, then one could infer the same could cause tink issues related to an unbalance momentum diameter. Or a change in the metal density could cause a resonance frequency change. You know, if we keep up this line of divergent thinking, we could qualify to be senior Ford design engineers.
 

·
Resident Rocket Scientist
Joined
·
11,997 Posts
ssr3 said:
Maybe the difference in length is not the issue. What about the drive shaft radius? Since small weight deviations cause major tire balance problems, then one could infer the same could cause tink issues related to an unbalance momentum diameter. Or a change in the metal density could cause a resonance frequency change. You know, if we keep up this line of divergent thinking, we could qualify to be senior Ford design engineers.
If we keep brainstorming we might come up with something. The change in the moment of inertia of the driveshaft due the temperature change is one more factor but... as I understand the issue, the 'tink' happens at a dead stop when the SSR is put into gear therefore on inertia involved other than the acceleration of the driveline that causes the tink..
Metal (Aluminum) density will not change appreciably with a 30 degree temperature change. Perhaps the acoustic properties change to where a different frequency is favored??
Something else I did not realize until reading some other threads is that the rear end (housing) is aluminum also. Maybe the driveshaft is the transmitter but the 'tink' starts elsewhere.
A challenge for the fanatics - On an SSR that 'tinks', get a volunteer to use a stethescope to search for the source of the tink. Working from trans to rear end listen to the tink at various locations along the driveline to determine the source. Once we know the true source we can start to figure out what's really going on.
 

·
Registered
2005 SSR
Joined
·
436 Posts
hdflstf

At 2500 miles I now get tinks going into gear, shifts from 1st to 2nd and on compression.

It seems to pretty much tink on any change.

I don't think I'm alone on this one.

Skip
 

·
Registered
Joined
·
1,502 Posts
Discussion Starter #8
Today it's different

Today I hear a creak instead of a tink. Yes a creak like a hinge that needs oil. Two dry metal parts rubbing against each.

I'm thinking this is from the same source as when as what causes the crack/ringing (tink) sound. It's two peices of metal that are moving with respect to each other that shouldn't be.

Looking at the service diagrams there are only two metal to metal joints that are tightly connected where torque could cause the stick/slip tink noise.

One is where the "propeller shaft bearing retainer" pg4-2 is used to bolt the rear universal joint to the pinion yoke. This dosen't seem likely. The universal seats quite deeply into the pinion yoke.

The other is where the "pinion yoke nut" holds the "pinion yoke" to the "pinion shaft". This is the one I'm wondering about.

Jim G, anyone: Do you know if the spline on the pinion shaft is tapered?

From the assembly instructions is seems they are. The pinion yoke is drawn onto the shaft by tightening the pinion nut. The pinion nut isn't torqued to a fixed value. It is tightened until the rotation of the pinion shaft requires a certain amount of torque to rotate.

I ask about the taper, because it's possible that the splines are seating not on the sides of the splines but on the tips. See attachment.

If they are seating on the tips; then the shaft under torque could spin a little in the yoke. Not much, but maybe enough to cause a crack noise.

So back to the heat. If the above is true, I haven't figured out how a 30 degree temp swing would make the stick/slip change.
 

Attachments

·
Original SSR Centerfold
Joined
·
3,146 Posts
When I first brought mine to the dealer with driveshaft "tink" the first thing they tried was to tighten the nut holding the yoke on the rear end. They said there was a bulliten(?) some time ago on the Trailblazer regarding this. Apparently some of the units were not tightened to torque at the factory. It didn't stop the "tink" but the mechanic did snug it up some.
 

·
Registered
2005 SSR
Joined
·
436 Posts
The other odd thing is that when people do get a replacement drive line there is no 'tink' for about 500 miles before it returns. If it was the yoke it would 'tink' right off the bat, so to speak.
 

·
Registered
Joined
·
1,502 Posts
Discussion Starter #11
SA13355 said:
The other odd thing is that when people do get a replacement drive line there is no 'tink' for about 500 miles before it returns. If it was the yoke it would 'tink' right off the bat, so to speak.
Not necessarialy. It could be loosening up under the stress of usage. Part of what the nut does is to crush a ring. Over crushing the ring calls for replacment of same.
 

·
Senior Privileged Member
Joined
·
4,100 Posts
Beer100: You have an interesting theory. Maybe the only way to tes the theory is to have someone who knows what they are doing align the two parts perfectly and then torque them to the correct torque value (whatever value that is?)?

I have no idea if that shaft is tapered or not.

Jim G
 

·
Registered
Joined
·
1,502 Posts
Discussion Starter #13 (Edited)
The stickey yoke theory

You said it, It's a theory.

I no longer think it's tapered. Just cylindrical, with a light press fit. The increasing levels of torque, that are measured when the pinion nut is tightened, have to come from the crush ring. As it is crushed it would take more torque to crush it additional amounts.

Steps 10-19 in this manual page are those that explain how the pinion yoke is attached. A light press fit. One that is a shade to light, would explain what is happening. That could do it too. Heat has an impact on fits. Lets see. I think the yoke is cast iron. But the pinion shaft would be steel. Maybe forged. 6.0 vs. 7.3. Yes! Steel expands more than cast iron. Ok, the fit would tighten up with heat. Tighter would make it more likely to stick and not slip. Or more heat = less tink.

Anyway, the manual makes it clear that there isn't any point where the yoke is actually clamped onto the pinion by the nut. Not solidly. The yoke and shaft are prevented from spinning by the splines and the fit of shaft to the yoke.

There is only one other place in the drive line might be sticking and slipping. I just don't know enough about the Torsen differential to know if there is an inherent reason for it to have small amounts of stick and slip.

Ok. So with the assumption that this is correct, what could be done. If the drive shaft is dropped, a long wrench could be used to torque the yoke and listen for the crack. But a fix, hummm.

Also how is it that after working on the propeller shaft the tink goes away for a short while. Theory doesn’t cover that, so what does tinkering with the drive line do to the yolk/pinion that makes is quiet for a while.

Fill in the splines.
Loosen the fit a little. Easy to do, and over do. Not good, the drive line would be free to slop around.
Tighten the fit. Very hard to do without replacing parts.

BTW: I'm in love with the idea of putting a 4.56 ratio ring and pinion on my SSR. Not real soon now. But within a year. Maybe I'll get a chance to check the theory myself.

PS. Everybody, this is fair notice. I do not intend to respond to requests to post other pages from the manual. I am relying on "fair use" to let me post portions. The link above is subject to removal at any time. PPS. don't expect any link on that page to work.
:)
 

·
Registered
Joined
·
1,502 Posts
Discussion Starter #14
I think I got it.

Working on the propeller shaft. Would involve some banging and knocking about. Even some judicious hammering, if the u-joint was stuck in the yoke, for instance.

I think that would tend to loosen the spline joint somewhat, enough that it didn't stick and have a chance to break loose.

BTW: Hammering on the yoke could cause problems with the pinion bearings.
 

·
Senior Privileged Member
Joined
·
4,100 Posts
beer100: The following line of text, highlighted even in red font on the page you posted, caught my attention:

"
Important
If the rotating torque is exceeded, the pinion will have to be removed and a new collapsible spacer installed.
"

This suggests to me that if the crush spacer is overtorqued, it's ability to provide enough friction is destroyed. It is POSSIBLE that if overtorqued, it would hold FOR A WHILE, but then gradually allow relative movement (because the springiness on which it depends has been destroyed via the overtorquing). So, after a faulty install in which overtorquing occurred (pretty likely I would say in the typical dealer shop!), it would hold for a hile, but then gradually fail to provide sufficient force and friction.

Possible?

Jim G
 

·
Original SSR Centerfold
Joined
·
3,146 Posts
Let me throw something else into this mess.

Could we be looking at the wrong end of the shaft? The service rep here was telling me that they had a similar problem a few years back on another vehicle. What they did at that time was to take a valve spring, slip it into the back of the tranny, pack in some heavy grease, and then slide in the driveshaft end. The spring kept the shaft from moving back and forth without some resistance and the grease muffled any noises.
Since the rear of the shaft is all pretty solid connections the 500 mile deal shouldn't come into play there. The front end has the play, lubrication, etc.

just a few thoughts to get minds working.
 

·
Senior Privileged Member
Joined
·
4,100 Posts
Dingbat: YOUR theory is supported by what happened on my SSR a couple months back: GM replaced the drievshaft, (front) yoke, and tailshaft seal because my vehicle developed a vibrartion at highway speed that they traced to the front yoke.

The replacement parts eliminated the vibration, and there is no ting, but I do have a ringing which could be coming from anywhere and just being amplifed by the aluminum driveshaft. Note that the tinging has not returned so far, even after at least 2000 miles.

Jim G
 

·
Registered
Joined
·
3,003 Posts
No Tink??

You guys are making me paranoid :confused I keep listening for a tink but so far nothing :) Maybe by the time I hear it in my truck, you"ll have it all figured out. Best of luck with that and thanks for sharing all your knowledge and ideas with the those of us who are, at best, mechanically challenged :rolleyes:
 

·
Registered
Joined
·
1,502 Posts
Discussion Starter #19
JimGnitecki said:
beer100: The following line of text, highlighted even in red font on the page you posted, caught my attention:

"
Important
If the rotating torque is exceeded, the pinion will have to be removed and a new collapsible spacer installed.
"

This suggests to me that if the crush spacer is overtorqued, it's ability to provide enough friction is destroyed. It is POSSIBLE that if overtorqued, it would hold FOR A WHILE, but then gradually allow relative movement (because the springiness on which it depends has been destroyed via the overtorquing). So, after a faulty install in which overtorquing occurred (pretty likely I would say in the typical dealer shop!), it would hold for a hile, but then gradually fail to provide sufficient force and friction.

Possible?

Jim G
I don't think so. I believe the crush ring is just a way to get an exact preload on the bearings. There would be a reliable 1-1 corespondance between the amount of preload generated and the wrench torque applied.

Over crushing the ring would preload the bearings too much, and once crushed it can't be undone without things getting sloppy.

No. I don't think the nut is intended to prevent small rotations between the pinion and yoke. It's more like how wheel hubs are held on the spindles. But without the play.

The silly thing is, if the yoke theroy is right, it would only happen with a precise amount of interference between the shaft and yoke. A little more and it sticks tightly, less and it rotates without sticktion.
 

·
Registered
Joined
·
1,502 Posts
Discussion Starter #20
JimGnitecki said:
Dingbat: YOUR theory is supported by what happened on my SSR a couple months back: GM replaced the drievshaft, (front) yoke, and tailshaft seal because my vehicle developed a vibrartion at highway speed that they traced to the front yoke.

The replacement parts eliminated the vibration, and there is no ting, but I do have a ringing which could be coming from anywhere and just being amplifed by the aluminum driveshaft. Note that the tinging has not returned so far, even after at least 2000 miles.

Jim G
People tend to try and fix the thing that is complained about. If complaints are about noise from the propeller shaft then; that must be the thing that needs to be fixed.

Often engineering groups try to fix the part that the complaints focus on. I don't know how compartmentalized GM is, but I could see one engineering group being responsible for the rear axel and another for the propeller shaft. Tunnel vision sometimes sets in, and there may be nobody that has both the perspective and/or authority to see the problem and direct a solution.

I can just hear the discussions... We use this rear end on xy and z, it dosen't make noise there. Only on w is there a noise, and it has an untried propeller shaft...
 
1 - 20 of 25 Posts
Top