Diff fix? - Page 2 - Alfa Romeo Bulletin Board & Forums
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post #16 of 37 (permalink) Old 10-31-2018, 06:39 PM
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Typical TV popular nonsense. Even a jamoke like me can figure out what makes sense and what doesn’t. I can’t stand that WD garbage, I’m not an “elitist” but I can smell BS. From a mile away.

Take it apart if that’s what you want to do, be curious and careful, and measure everything with eyes, touch and quantitative means. Use common sense above all.

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post #17 of 37 (permalink) Old 10-31-2018, 08:02 PM
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Originally Posted by Stevew View Post
In the Wheeler Dealer episode, the mechanic added an extra plate to the new ones he installed and all was well.
FORGET WHEELER DEALERS! Forget taking your diff apart!

Driveline clunks are common on Alfas, and are caused by worn parts in the driveshaft 99% of the time. Yes, it could also be in something in the clutch or the result of sagging motor mounts, but your limited-slip clutches are about the 56th thing you should be worrying about.
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post #18 of 37 (permalink) Old 10-31-2018, 09:22 PM
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FWIW - I swapped my 1600 differential for '74 LSD FROM A 2L. To check its status I took the steel axle side off and removed the stuff inside after a bit of work, I found that I had 4 plates on each side - 2 plates, and 2 friction discs. They were installed 1122 for normal use. But it was also trivial to stack them 1212 to get a much higher lock-out. (said to be 70% or so).

Makes there rear end great for a 4 wheel drift out of a fast turn on the race track, but doesn't really add much to street use. Either one does not engage much in the normal "tooling around" driving we mostly do.

But watch out if you don't have any experience with the higher lock up setup. If you like "vigorous" driving on the winding back roads on the weekend, you can end up off the road faster than you can blink.

Robert
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post #19 of 37 (permalink) Old 10-31-2018, 11:31 PM
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x2 it's the diff. Mine has also always clunked. It behaves just like one I had in an old BMW years ago; it was cheap enough to find a better one and drop it in.
My guibo was replaced in '15, along with all mounts. Rear bearings replaced, rear diff re-sealed. Guy who did the work just told me to drive it that way, but it still bugs me.
I can turn the wheel quite a bit until the rear diff engages, same with the driveline. Clunk clunk clunk...

A friend of mine has (had) a spare that had much less play, but he wants ~$400 IIRC.

Clunk.
John

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post #20 of 37 (permalink) Old 11-01-2018, 12:46 AM
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Steve - one more thing. When I opened my diff by removing the steel side axle that covers the diff, I was able to remove the internals easily. Of course I couldn't test the ring - pinion mesh, but I could inspect all the parts carefully, especially the LSD clutch disks.

RJ (Alfa7)has a thread in here somewhere on how to refurbish the clutch plates buy removing the burnt varnish that collects. He's one of the most experienced Alfa mechanics and racers on the BB, and will give you a lot of advice on your diff ( and a lot of other things too!) by phone that might not appear on the BB. Be respectful of his time and expertise - he's pretty busy and sometimes grumpy (like me!).

When I reassembled the TX, I had no problems. I had the assembly checked by an experience Alfa mechanic, but he found no need to alter any shims. Of course, I didn't have any clunk either, which may require a complex process that requires some special Alfa tools to to right. But you can at least inspect the internals and confidently reassemble them to the same state as when you opened it.

Good Luck

Robert
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post #21 of 37 (permalink) Old 11-01-2018, 09:06 AM
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There are also the rubber bushings for the reaction T at the top of the diff. If those are missing or worn then wouldn't the whole rear axle assemble roll back and forth a little bit? Sorry, foggy memory, could be blowing smoke, not likely blowing bananas.......

Cheers,

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post #22 of 37 (permalink) Old 11-01-2018, 09:10 AM
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Quote:
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There are also the rubber bushings for the reaction T at the top of the diff. If those are missing or worn then wouldn't the whole rear axle assemble roll back and forth a little bit? Sorry, foggy memory, could be blowing smoke, not likely blowing bananas.......
That'll cause rear axle steering. The test is if you get the car going at about 10mph, take your hands off the wheel, and can steer the car left and right with the throttle those bushings are likely bad.

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post #23 of 37 (permalink) Old 11-01-2018, 09:26 AM
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Quote:
But watch out if you don't have any experience with the higher lock up setup. If you like "vigorous" driving on the winding back roads on the weekend, you can end up off the road faster than you can blink.
Particularly if the road is wet.

Ed Prytherch
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A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #24 of 37 (permalink) Old 11-08-2018, 03:59 PM
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I donít think itís your differential at all. I had it in my car and chased down the likely source. You can find a good thread on BB with a careful search.

I forget the exact method, but basically itís one of your rear springs moving around.

Never too many Alfas
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post #25 of 37 (permalink) Old 11-08-2018, 04:34 PM Thread Starter
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Instant Notification...or not.

Seemed mighty quiet on the "Diff Fix" front and I just discovered, via Spiderbill's post and IN to my Yahoo! account, that quite a few members had weighed in with advice.

Thanks, all!

My Quad has been backed up on ramps for several days and tomorrow morning I plan to go under and check all the "usual suspects" that have been suggested. As I recall, I had to thin an open end wrench to access fasteners attaching the drive line to the diff (I'll remember to mark the pieces so balance is preserved) and I'll go through that step to isolate the diff.

Regarding my subject line, I visited my CP and confirmed I'm signed up for IM, but they did not appear till today. Not in spam, either. Hmmm, just noticed IM is enabled below, too.

I checked and unchecked the box in CP, then saved, so I'll see. Also having issues on a Duramax site, so maybe it's me.

Best!

Steve Waclo Carson City, NV; '87 Spider QV, ES Champion, 2018 Reno SCCA (125k);'93 Honda Nighthawk 750 (105k);'03 GMC Sierra SLE 2500HD Turbo Diesel (155k);'08 Altima Coupe 3.5SE, 6sp (125k)

Last edited by Stevew; 11-08-2018 at 04:36 PM. Reason: Afterthought
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post #26 of 37 (permalink) Old 11-09-2018, 08:39 AM
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LSD issues

I took the time to write a thread on re-building (re-clearancing) the LSD units. It`s on my Technical post so it can be found easier. The link is:
https://www.alfabb.com/bb/forums/eng...ml#post8336934
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post #27 of 37 (permalink) Old 11-09-2018, 11:47 AM
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Thanks Richard. You are generous with your knowledge! All of us really appreciate this!

Robert
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post #28 of 37 (permalink) Old 11-09-2018, 10:30 PM Thread Starter
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Inconclusive

Hey gang!

Crawled out from under my car about an hour ago, after a review of all the advice offered here (thanks) and here's my report:

Executive Summary:

After many checks, including shaking, pounding and twisting, still no definite diagnosis...only a theory.

First, I went for the low hanging fruit and checked the center drive shaft carrier, which I replaced shortly after I bought the car due to thumping against the body. Vigorous shaking (VS) showed it to be sound and intact.

Next, with trans in gear, I rotated the DS and observed and listened for issues at each U joint. Also did those a while back and they appear sound. Ditto for the big rubber doughnut. No play seen or heard.

Rear transmission mount survived VS with no indication of looseness. Front mounts are the aluminum reinforced type and I checked them a while back, bonnet up, parking brake on, first gear and looking for engine rotation. Solid.

Went to the rear suspension and got hands on everything in sight (including the upper suspension member) applying VS. OK

Next, I disconnected the rear end of the drive shaft from the differential input. When I did this year's ago, to replace a leaking seal, the fasteners were nearly seized and that's when I had to grind down the outer circumference of a 13mm (?) box wrench to fit around the bolt heads. This time two open end wrenches got the job done. Permanent marker used for refitting. There's an alignment lip on the driveshaft side, so a couple of light taps separated the driveshaft.

On a side note, I don't believe checking differential play with the DS connected is helpful (unless all is snug, then no problemo) since rotating everything as a unit is not informative as there are too many variables at play.

Note, at this point, I jacked the rear axle a bit more to free the tires, and placed jack stands appropriately. Parking brake on.

Using just my hand, I rotated the diff input and measured (numerous times) total displacement of the input. Afraid I really exaggerated before, because this time, only 1/4". Vigorous hand rotation of the diff produced no sounds other than a mild bump (is that a sound?).

Decided I needed to apply more torque, so I attached my 00 vice grips to the diff input and rotated again (with vigor).

CLANK!

OK, thought I was onto something and used a stethoscope (RN type) to track the noise. Diff was nominal, axle, the same but a distinct clank when listening at the brake dust shield on either end.

False alarm, unfortunately. I took off the DS wheel and disk and learned that with my PB on full, the axle hub will rotate the captured PB/rotor assembly through about 1/2", with a clunk at each extreme. Confirmed by putting the rotor on backward, covering just part of the PB shoes and with the PB on, could watch the shoes move CW and CCW. Who knew? Or is it just my car. Makes no nevermind anyway, since it does not relate to my issue.

While I had the rotor off, I jammed my vice grips onto the diff input to lock it up and checked axle rotation at the DS wheel. The hub moved about 3/8" total and vigorous rocking produced only the aforementioned bump sound.

Sigh...

Found the cold chisel, whose back end I had ground down to fit the diff filler and checked the fluid level. Seemed a bit low, but with the car on ramps, hard to say.

Put a drain pan in place and dumped my Oreiley's gear oil (I know, I know, I'll look for Redline but wonder if I would be wasting $$$). I'm guessing 10k on the oil (man, I gotta keep records) and it came out quite dark. Also, fine, dark metallic fur on the drain magnet.

Just remembered something else. Last year, I had a buddy rock the car in 1st (engine off, natch) while I bravely stuck my head under the rear end and listened. My recollection is a slightly subdued version of the previously described clank, fore and aft, coming from, as nearly as I could tell, the diff.

Richard, your description of how to disassemble the differential from the driver's side is intriguing and I'll have to read it again more closely. No lift available so everything would need to be done on jack stands, but better than a complete axle drop.

Oh, did I mention? I really think there are gremlins in my differential, although I could be persuaded otherwise. Many times I have gone through a list of suggestions and put options behind, only to discover the problem was one of the items I thought I checked.

A final thought (definately not from Mark Twain): "It ain't what you know gets you in trouble. It's what you think you know that just ain't so."

Best

Steve Waclo Carson City, NV; '87 Spider QV, ES Champion, 2018 Reno SCCA (125k);'93 Honda Nighthawk 750 (105k);'03 GMC Sierra SLE 2500HD Turbo Diesel (155k);'08 Altima Coupe 3.5SE, 6sp (125k)

Last edited by Stevew; 11-09-2018 at 10:38 PM. Reason: 12 years of Catholic School
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post #29 of 37 (permalink) Old 11-09-2018, 11:21 PM Thread Starter
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More wisdom from Alfar7

Richard,

While reviewing your linked post (above) I found this in earlier pages. More detailed 411 you offered on checking LSD's at the pinion:
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Steve Waclo Carson City, NV; '87 Spider QV, ES Champion, 2018 Reno SCCA (125k);'93 Honda Nighthawk 750 (105k);'03 GMC Sierra SLE 2500HD Turbo Diesel (155k);'08 Altima Coupe 3.5SE, 6sp (125k)
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post #30 of 37 (permalink) Old 11-10-2018, 10:27 AM
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Diff

Well with the diff out you can inspect teeth (razor sharp edges on the pinior or ring gear indicate preload clearances issue) and the metalic fuzz is 99% going to be LSD wear from clutch plate/clutch disk wear.

Order Redline NS from Centerline. 2 Qts will be a half pint more than a dry case will need.

Richard Jemison
RJR Racing

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