Axle - or - Differential Problem ?

[ARCHINSTL]

Last night near my house, while turning left, I heard a kinda loud, sort of metal-against-metal sound and some throbbing. It seemed to emanate from the right side. The noise disappeared in the straight-ahead position, and it seemed to drive OK the remaining couple of blocks.
So - today I raised the front end and shook everything, with no result. The axles turned OK, with no noises or vibrations, etc.
Then, while up on jackstands, I started the engine and put it into gear. I turned the wheels left and right with no noises.
Then - I noticed the DS wheel seemed to be turning at the same speed, whether full left lock or full right lock - then - I noticed the PS wheel was barely turning, regardless of the lock.
In the straight-ahead position - the PS wheel barely turned with little shakes...I could even rotate it backwards by hand, while the DS wheel was rotating at an "appropriate speed."
Opinions (shudder) ?
Tom M.

[garyfish]

similar problem (?) discussed in the following thread:

viewtopic.php?f=4&t=3692

Good luck, & keep us posted

[takza]

I'm afraid that this is what's going to happen to mine after running it in metal soup for a few K...might even try the Restore in the gearbox...though I do have moly in it now. Still spinning the tires on occasion...

In Arches case...you would expect one wheel to turn and the other not to...due to one side being tied to the ring gear and the other not...so all is not over yet?

[Petros]

a bad PS wheel bearing could cause drag, or a lockup caliper, or a frozen CV joint, and not allow it to turn. If there is in-and-out play in the bearing it would allow the disk to rub against the caliper. See if you can find where it was scraping, that should tell you what is loose.

I doubt it is in the diff, because whether you turn left or right should not change the loads in the diff. IT sounds like the scraping occurs when there is lateral loads on the suspension, which would not transmit to the diff through the axle. Also see if the suspension has worn parts or bushes that allow the wheel or hub to rub against something.

Good luck.

[ARCHINSTL]

Petros - OK - please excuse my ignorance here -
When elevated and running, one wheel should be turning at speed and the other should not? And the non-turning wheel can be moved backwards? This did not seem correct to me, whence my thoughts on it being the differential.
Looking at drawings and explanations of how differentials work, it seemed that in a turn they turned the outside wheel faster than the inside wheel - that is how I thought they functioned. I ain't no dummy, but diffs have aways seemed arcane to me.
No matter which way I turned the wheels, the DS sped on, while the PS just bumbled along, barely moving.

So - what you are saying is that it is unlikely it is the differential, despite one wheel turning and one not - even in the straight-ahead position?

As mentioned, without power, the wheel spun freely, so I do not think the caliper was locked up - I am kinda familiar with this, as the PS side on my Dodge/Mitsu p'up did this twice, with different OE calipers. The wheel would not turn, and "kinda heated up" the wheel.

My first thoughts were that something was rubbing on the right side at any left lock - I heard no grumbling/rumbling cacophony of any type from the transmission and, as mentioned, the car ran/felt just fine after noticing the noise - no pulling to one side, and no untoward noises coming from the transmission.
I did think that maybe this could be a wheel bearing - until I lifted the front and noticed that the DS wheel spun and the PS did not.

As far as suspension bits - ALL bushings, springs, strut inserts, ball joints, and inner and outer tie rods were replaced in late '07, so it would seem the suspension can be ruled out. New calipers and rotors were installed in '06 (original backing plates, though). OE PS steering rack mounts were new in '07.

I guess your first recommendation is to remove the caliper and inspect both it and the rotor for some impressive scrapes? Perhaps I can remove the caliper, place a spacer between the pads, and suspend it securely from the strut (leaving the rotor in situ), and driving around the neighborhood at night to see if the sound is still there; it it disappears, it would be the bearing - if not, on to the axle. Does this seem like a reasonable procedure - or just harebrained?

Would the next step be to replace the PS axle to see if it is the problem? I still have the axles I removed last year, so I would not have to call GSP for another one to use as a test. Reusing the old one, at least temporarily, could be a hint as well.

If the diff - then this is the first time I doubt my abilities to work on this car...

All - Thanks for your words.
Tom M.

[Petros]

a normal working diff can have both wheels turning in opposite directions with both wheels off the ground. That is the way the spider gears in the center of the diff work, they have to be loaded the same to turn the same direction, and to allow "differential speed" to each wheel in a turn. If one wheel or the other has extra drag on it the wheels could act as you describe.

How hard is it to get to front cover on the diff? I think it can be removed with the trans in the car without too much trouble (all the oil will drain out). But you can inspect the spider gears and ring gear if you pull the front cover. It seems to me if these spider gears are trashed it would not drive forward at all, and it would make a lot of bad noises anytime you are moving forward. That is why I think what you describe is not quite consistent with a failed diff, but I suppose it is possible (diff failures are pretty rare, but I have seen them before). But you could know for sure by pulling the front cover.

I am not sure I would go to the trouble of swapping out the axle unless you were reasonably certain that was it, when the CV joint fails or shows wear they start a clunking or throbbing when accelerating in a turn.

My experience is that scraping sounds that are not from the brakes are usually a bearing wearing out. They get sloppy and will make a different sound in a turn than straight. The Tercel uses a sealed front bearing that must be pressed out, the easiest way to do this job yourself is to remove the front hub and take it to a shop and pay them to press it out, and press in the new one (I think most NAPA stores can do this, and sell you a new bearing). Again make sure it is the bearing before you pull the car apart.

Good luck.

[ARCHINSTL]

Thanks for the words - I feel (somewhat) better.
It also seemed reasonable to me that if something were really amiss in the trans/diff that there would be some (literal) "gnashing of teeth." It was just as "quiet" after the noise as it was before.
I will work on checking the bearing first. It will probably be a couple of days before I can report back.
Tom M.

[takza]

The way to test the spider gears is in a turn at slow speed...as you turn...if a spider gear has lost teeth...you'll know it.

[splatterdog]

The "one wheel wonder" is often due to brakes drag differences and driveline dynamics take part too. Hopefully just pads stuck in the bracket and not a sticky piston. Or it's just normal.....

I see this almost every time when checking wheel bearings. Which is your next step. Use a mech's stethoscope(they are real cheap) or just a long screwdriver with the handle pressed against your ear and the tip on the knuckle as close to the bearing as safely possible. Usually it's obvious but sometimes you will need to hit at least 35-50 mph to make a non loaded bearing make noise. Make sure the car is secure before you get under it! Also check at the trans too in the same manner. There will be some noise from the diff when one wheel is turning. But that's gear noise and not bearing grumble.

Because of the one wheel wonder and sometimes I like to check bearings one at a time, I use a prybar on the caliper in a manner that will pull the outer pad into the rotor. If you are unconfortable doing two things at once you can spin one at a time by sticking a screwdriver or prybar thru the wheel against the strut or caliper to hold it before you spin it. Just make sure it's at it's stop point so it doesn't slam it there when you let the clutch out.

Takza- get the metal soup out of that trans! My 84 came with shockingly bad oil. That was almost 10 years ago. Flushing and switching to synthetic have kept it working as good as "new to me" It also helps to keep the flogging to a minimum.....

[ARCHINSTL]

OK - I waited two weeks before reporting on this to make certain my "fix" worked...
What I did...
I elevated the front end again, and both wheels seemed to "spin" with the same resistance (I did not start the engine this time).
I removed the wheel and the caliper and the hub/rotor seemed to spin OK.
Then I noticed what appeared to be a pebble between the rotor and the backing plate, which fell out when I removed the rotor. I mean, this thing was less than a centimeter across. It was not magnetic and was not brass etc. It was shiny on one side, indicating having been rubbed. Since it almost appeared to have fibre strands embedded in it, I thought it was a chunk of a brake pad. Careful examination of the pads revealed no missing material, and nothing was amiss with the caliper or backing plate.
I buttoned it back up and have put on almost 200 miles with no return of the problem.
Apparently something "largish" was thown into the gap and was being worn down by the rotor, causing the drag and alarming sounds. Sure wish I knew what it was...must have entered at just the right angle.

So - Thanks to all for their comments!
Tom M.

[takza]

Takza- get the metal soup out of that trans! My 84 came with shockingly bad oil. That was almost 10 years ago. Flushing and switching to synthetic have kept it working as good as "new to me" It also helps to keep the flogging to a minimum.....

The metal soup is long gone...though it took an extra oil change to do it...seems there was enough hung up on the gears and case to show up in the first change....after the 2nd change...I drained some after driving it some and found no metallic oil. Still running on this oil with moly. Thought the diff would be messed up...but it seems normal. A trans bearing went...