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Curious Vibration While Coasting

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    #31
    yeah they go back and forth, but its not a full rotation by any stretch. The actual needle itself might make a full roll but the inner shaft relative to the outer cup doesn't move very much.
    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC grandpa spec white and cranberry

    1984 Lincoln Continental TurboDiesel - rolls coal

    Originally posted by phayzer5
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

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      #32
      Originally posted by DerekTheGreat View Post
      I watched Eric The Car Guy rebuild an 8.8 and said F that. You guys that have the patience for that, good on ya.
      Shit the 8.8 is a walk in the park, try a larger Dana, like a 70 or 80 - not only is everything inside the bitch heavy as all gets, but the preload shims for the large diff bearings are actually squished between said bearings and the carrier itself - get the shim stack thickness wrong and you're fucked, unless you got a $600 tool that can pull the bearing without destroying it. Oh and you should use setup bearings for this shit, which are basically normal bearings but with an ID that allows them to slide down onto the carrier snouts instead of pressing onto them, so you can fuck with the shim stack easier. Oh and did I mention you really wanna have a case-spreader too, which is of course more or less axle-specific, so if you got one for a Dana 44 it may or may not work for a Dana 80 for instance.
      The ones who accomplish true greatness, are the foolish who keep pressing onward.
      The ones who accomplish nothing, are the wise who know when to quit.

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        #33
        Originally posted by IPreferDIY View Post
        U-joint related play and clunking aren't issues. I'm getting a bit of funny vibration during the transition from powered to coasting movement, but only at highway speed. I would guess that the one axis that had freer movement (but without slop) is the culprit, and I'll find out soon enough; but in the absence of an emergency, I’m not climbing under my car again until the weather warms up. What’s wrong with wanting to learn how things work in the meantime? I’d love to be able to spend some more time learning more about the Riemann hypothesis, but there doesn’t seem to be much chance of that being productive until my eyes are finally fixed.

        I turns out that the hybrid U-joints aren't astronomically priced like I thought they would be (as a 'specialty part'), so I'll probably go for whatever decent CVPI aluminum driveshaft comes my way rather than hope for an older one that uses 1330s. I should be able to get price-matching on Spicers (at least the 1330s) at a local place. I would want to be able to use the driveshaft in something else when my current car reaches the end of its life, so I won't cheap out on those.
        Hey nothing wrong with learning, I just thought you're chasing gremlins where either the aren't any or they should be fairly obvious. Consider this for your vibration - Spicer joints have a plastic thrust washer between the cap and the face of the trunion, if that washer is worn out it will allow the shaft to slide sideways across the U-joint some, which will certainly cause vibrations at some driving conditions or others. Notice that because the motion of the shaft with respect to the yoke is radial and not torsional, you may never feel the joint being loose, since it actually is not loose in the typical sense of the word as the needles are still doing exactly what they're supposed to be doing.

        I got a 1330-1350 convo joint for like under $20 at the local NAPA, tho they do give me a bit of discount there so idk what retail actually is on it. Made in Japan too, I'll take that over China or India any day!
        The ones who accomplish true greatness, are the foolish who keep pressing onward.
        The ones who accomplish nothing, are the wise who know when to quit.

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          #34
          Walk in the park to you maybe. Seems so tedious trying to get the backlash and all that right. If I had the tools and stuff I wouldn't mind tackling any of it but that's where I usually fall short.
          1985 LTD Crown Victoria - SOLD
          1988 Town Car Signature - Current Party Barge

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            #35
            Oh starting from scratch any gear setup is a bitch. But the nice thing about Ford axles (both the 8.8 and the larger 10.25 and 10.5) is that they are VERY consistent in their tolerances, meaning if you are installing factory gears from another axle just keep the pinion depth shim with its respective pinion and the carrier bearings preload spacers with the respective axle and 9 times out of 10 you'll get both backlash and patter right on. If you're just rebuilding an axle with new bearings it's even easier, just pull old junk out/off and press new stuff in/on, unless you're very unlucky you'll be good to go. I've run into some that have the carrier is loose even with new bearings, those you gotta start messing with the shim stacks for the carrier preload and gears backlash, but even so at least you're not dicking with the pinion depth - I had to redo all of those specs on my D80 cause the bearings were worn but still in great shape (if that makes any sense), that was anything but fun of a job.
            The ones who accomplish true greatness, are the foolish who keep pressing onward.
            The ones who accomplish nothing, are the wise who know when to quit.

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              #36
              Oh wow, I didn't know that. From all the frustration Eric had I thought that was just common. I wondered if you could just reuse the shims when changing gear sets. But also, isn't the contact pattern of the gears affected by the shims and such?
              1985 LTD Crown Victoria - SOLD
              1988 Town Car Signature - Current Party Barge

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                #37
                Yes contact pattern is directly affected by the shims. That is why you keep the pinion shim with the pinion, and the housing/carrier spacers with the housing. The shims and spacers are not a wear item, the bearings are - replace your bearings and you're back to factory specs, maybe a tiny bit looser cause of gears being worn out, but they really shouldn't wear any noticeable amount. Most of the time even with a gear swap as long as you're using factory gears and your "new" pinion still has a shim on it things go smoothly with little to no special work needed. I do not watch Eric the Car Guy, or anything else on youtube for that matter, so I don't know what issues he was having - but I have run into IIRC two axles where new bearings with the factory shims still ended up bit too loose on the carrier bearings preload for my liking, they were in spec as far as backlash goes but the bearing preload just didn't give me that warm and fuzzy feeling inside. And once you're messing with the side spacers to obtain proper carrier bearing preload, you can use that opportunity to shift the carrier around till you get a better backlash and gear contact pattern.
                The ones who accomplish true greatness, are the foolish who keep pressing onward.
                The ones who accomplish nothing, are the wise who know when to quit.

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                  #38
                  If aftermarket gears or carriers are in play, that may change it. OE Ford parts are made pretty consistent, but the China-made gears may not be so precise.

                  I want to say one of the shims on my Towncar was damaged for some reason. Scott replaced it with one out of his drawer of parts that was the same size and it all went together fine.
                  Last edited by gadget73; 02-17-2017, 05:33 PM.
                  86 Lincoln Town Car (Galactica).
                  5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                  91 Lincoln Mark VII LSC grandpa spec white and cranberry

                  1984 Lincoln Continental TurboDiesel - rolls coal

                  Originally posted by phayzer5
                  I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                  Comment


                    #39
                    Just figures I was the 1 in 10 that didn't like the result with a new Ford 31sp carrier and gears with the stock shims. Ended up changing pinion depth and backlash. I also wasn't talented enough to stack aftermarket carrier shims. Anyone that can do that gets my admiration. Luckily one of the local dealers had the factory ones I needed in stock. I vowed to never take that on again myself. Then again, don't know if I would trust an unknown person not to say good enough and just slap it together.
                    sigpic
                    89 LTC 429>557 Cobrajet stroker
                    13 F-150 XLT 6.2 l
                    "If I could separate what's real from what I've been dreaming I could live to fight another day"

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                      #40
                      Setting gears up on any mechanical thing is not really that hard, you just have to follow the procedure and use the right tools. Stuff using shims is more tedious than hard, but it can get hard if it comes apart in a retarded manner.
                      86 Lincoln Town Car (Galactica).
                      5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                      91 Lincoln Mark VII LSC grandpa spec white and cranberry

                      1984 Lincoln Continental TurboDiesel - rolls coal

                      Originally posted by phayzer5
                      I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                      Comment


                        #41
                        Yeah, it's mostly annoying than hard really. Well it gets hard on you when you're working with something that has a ring gear about a foot in diameter, and it's exponentially worse as the size increases. But yeah, patience is the main ingredient, Prussian blue (for used gears) or yellow paste (for new gears) would be the close second. Add limited slip internal shimming for extra fun
                        The ones who accomplish true greatness, are the foolish who keep pressing onward.
                        The ones who accomplish nothing, are the wise who know when to quit.

                        Comment


                          #42
                          You ever work on a two speed rear end? I'd like to see one of those all taken apart and then put back together.
                          1985 LTD Crown Victoria - SOLD
                          1988 Town Car Signature - Current Party Barge

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                            #43
                            I got one, but it's low mileage (for a commercial-grade vehicle) and works extremely well so I have no reason to dive into it. I do recall someone on Pirate doing a rebuild on one of those with good pictures and explanations, gotta see if I either bookmarked it or PDF-ed it... Why, you thinking of putting one in your Towncar?
                            The ones who accomplish true greatness, are the foolish who keep pressing onward.
                            The ones who accomplish nothing, are the wise who know when to quit.

                            Comment


                              #44
                              Originally posted by His Royal Ghostliness View Post
                              ... Consider this for your vibration - Spicer joints have a plastic thrust washer between the cap and the face of the trunion, if that washer is worn out it will allow the shaft to slide sideways across the U-joint some, which will certainly cause vibrations at some driving conditions or others. ...
                              Since one axis was moving freer than the others, but without any slop, that would seem to be the most likely explanation at this point. We had an amazingly warm day on Saturday, so hopefully we're emerging out of the deep freeze. Interestingly, the problem didn't seem to be there when it was warm out, but it reappeared when things cooled down.

                              2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
                              mods: air filter box 'tuba', headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, KYB Gas-A-Just shocks, aluminum driveshaft, ARA3 PCM

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                                #45
                                You might be having some lubrication issues there. The plastic thrust washers generally don't give a hoot about ambient temperature, but the grease there sure does. One way to find this out, pop the U-joints apart and have a look-see.
                                The ones who accomplish true greatness, are the foolish who keep pressing onward.
                                The ones who accomplish nothing, are the wise who know when to quit.

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