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3.54 install, noise when coasting |
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amc401t10
AMC Addicted Joined: Mar/09/2009 Location: east tn Status: Offline Points: 903 |
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Posted: Jun/25/2017 at 10:15am |
finally got 3.54 install in and running. good pattern on drive and coast side of ring. got the shim right, nice pattern, .065 behind pinin race, stock carier shims worked , got .008 backlash. don't have in lbs torque wrench, got the pinion bearing set to just a little drag when I turn it. test drive car. I like it! drive bout 50-60 miles now and a noise (bearing noise) happens under down hill coast when slowing down. completely stops bout 20 mph or slower. I'm pretty sure that when the carrier is driving the pinion the pinion bearings are whats under load. so questions, pinion bearing too tight , or loose, ?(bet its too loose,i set it like wheel bearings) if u touch the gas when noise happens , it stops. the longer u drive and thin the oil , the louder the noise gets HELP thanks |
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1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727 84 j10 ,360, 727 1970 4-door rebel sleeper(455 pontiac,turbo 400) 79 spirit,4.2 |
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vinny
Supporter of TheAMCForum Joined: Jan/05/2012 Location: Calgary Status: Offline Points: 2837 |
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The only thing I could suggest is to have a pro look at the pattern and set up to see if any changes are needed.
Years ago some kids were burning out in our 65 Mercury landscape pick up truck and broke the carrier retaining bolts, which caused kind of a mess. I remember a neighbor retired mechanic, who still smoked and had only one lung left, taking a few days to put it back together with parts from a much older truck. Although that rear end no longer had positrac it ran quiet as a new one. I kind of wish I had stuck around to learn how he did it. |
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tufcj
Supporter of TheAMCForum Supporter of TheAMCForum Joined: Jul/10/2007 Location: Watkins, CO Status: Offline Points: 4085 |
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Noise on decel isn't going to destroy the rear. More of an annoyance than anything else. My 2003 chevy pickup has a slight whine on decel since I got it w/22K miles, it now has nearly 200K. It did lessen with a full synth gear oil.
That said. 15-25 inch pounds is more than just a little drag, you'd be surprised. That will affect pinion depth. Pinion depth will affect backlash. On backlash, .008" is preferred, but going to either end of the .005-.009 scale is OK to get a good pattern. The teeth of the pinion are like a screw. When you're under power, it's pushing against the housing and the bearing at the head of the pinion. Under decel, it's pulling the pinion into the housing, putting the load on the yoke-end bearing. Any movement will affect both backlash and gear pattern. Did you use new or used gears? Bob tufcj |
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69 AMX
74 Javelin AMX 67 Rogue If you need a tool and don't buy it... you'll eventually pay for it... and not have it. Henry Ford |
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amc401t10
AMC Addicted Joined: Mar/09/2009 Location: east tn Status: Offline Points: 903 |
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new gears. and bearings. yes my 4.11 in my gremlin slight whine on coasting but nothing like what I'm getting. ill try to tighten the yoke nut a little and c if it changes. thanks
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1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727 84 j10 ,360, 727 1970 4-door rebel sleeper(455 pontiac,turbo 400) 79 spirit,4.2 |
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Mopar_guy
Supporter of TheAMCForum Joined: Jun/07/2009 Location: Ohio Status: Offline Points: 4823 |
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Since you used new gears, did you do the proper break in on them?
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"Hemilina" My 1973, 5.7 Hemi swapped Javelin |
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Airdrie AMX
AMC Nut Joined: Aug/08/2010 Location: Alberta, Canada Status: Offline Points: 329 |
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If you set the pinion bearind preload like wheel bearings don't drive the car until you set it up to 15-25 inch pounds, a loose pinion bearing will ruin a gear set.
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72 amx javelin 401 4spd
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amc401t10
AMC Addicted Joined: Mar/09/2009 Location: east tn Status: Offline Points: 903 |
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it was play in the pinion . I locktited and staked the nut during install. I must not have got it tight enough. tightened it up last night to ?some drag when turning?. and put it back together. drove it today 50-60 miles, all seems ok. ill check it again in a couple hundred miles. ps its quiet as a brand new car! lol mabe, ive got 2.5 exhaust with flowmasters, ending in front of the rear end! |
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1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727 84 j10 ,360, 727 1970 4-door rebel sleeper(455 pontiac,turbo 400) 79 spirit,4.2 |
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Airdrie AMX
AMC Nut Joined: Aug/08/2010 Location: Alberta, Canada Status: Offline Points: 329 |
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That's good news, it takes more force than you would think to turn the pinion @ 25 inch pounds. Of course this is measured with the carrier out, with the carrier in and axles installed it's just a guess. I'm sure it will be fine, in my younger days I swapped out broken yokes on my jeep rattling them on with an impact LOL, never had an issue.
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72 amx javelin 401 4spd
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FSJunkie
AMC Addicted Joined: Jan/09/2011 Location: Flagstaff, AZ Status: Offline Points: 4742 |
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It should take 200 foot pounds or more on the pinion nut to produce a bearing preload of 17-28 inch pounds if you have a good crush sleeve in there. A properly preloaded pinion is hard to turn by gripping the pinion yoke with your bare hand. It's quite a bit of drag. If you are able to achieve that proper level of drag (preload) with the nut tightened to less than 200 foot pounds, then you either don't have a crush sleeve or it has already been crushed before. Without a crush sleeve or with an already crushed sleeve, all the compression pressure from the pinion nut will preload the bearings, so very little torque on the nut will achieve the proper preload. It's the crush sleeve's job to absorb most of that compression force so that very little of it preloads the bearings. That way you can have the pinion nut cranked down really tight without overloading the bearings. |
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1955 Packard
1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited |
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amc401t10
AMC Addicted Joined: Mar/09/2009 Location: east tn Status: Offline Points: 903 |
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thanks all
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1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727 84 j10 ,360, 727 1970 4-door rebel sleeper(455 pontiac,turbo 400) 79 spirit,4.2 |
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