What carrier is this? And is this noise normal?
03-20-2012, 06:38 PM
#1
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What carrier is this? And is this noise normal? I bought a 12 bolt that had a locker in it supposedly. After install, I noticed that at lower speeds, it makes loud popping noises in turns(I know lockers are supposed to ratchet, but I honestly assumed it would make a mechanical sound, not a sound that seemed like it was binding and popping, which I am wondering if this is normal).
I decided that for the hell of it, I'd pull the diff cover to drain the fluid and inspect everything. This is what I found.
Now correct me if I'm wrong, but that looks like a posi to me. And if that is the case, what would cause my low speed popping and such?
I decided that for the hell of it, I'd pull the diff cover to drain the fluid and inspect everything. This is what I found.
Now correct me if I'm wrong, but that looks like a posi to me. And if that is the case, what would cause my low speed popping and such?
03-20-2012, 07:07 PM
#2
Yes that is a posi and what you hear is clutch chatter. Eitehr the posi is too tight but I doubt it since it has preload springs in it so no one attempted to tune the posi and shimmed it too tight. Add 2 bottles of GM axle additive and then do figure of 8 turns, it should allow the clutches to slip more and the popping noise should go away.
03-20-2012, 08:23 PM
#5
Yes that is a posi and what you hear is clutch chatter. Eitehr the posi is too tight but I doubt it since it has preload springs in it so no one attempted to tune the posi and shimmed it too tight. Add 2 bottles of GM axle additive and then do figure of 8 turns, it should allow the clutches to slip more and the popping noise should go away.
Al 95 Z28
03-20-2012, 09:18 PM
#7
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Not to be a thread jacker here but I have a stock 01 Trans Am and I have only driven it a hand full of times but tonight after I beat on it a little bit, I noticed a light popping noise coming from the rear end on a sweeping low speed (20-25mph) curve. The axle did not hop nor did it feel like it was binding up. The noise was not always present in turns. The noise sounded like it was out of the left rear. I made some tighter turns but could not duplicate the noise in a tight turn. I do know the rear pinion seal is leaking but I topped off the fluid saturday for the time being. Any suggestion as to what the noise might be?
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03-20-2012, 10:53 PM
#8
Not to be a thread jacker here but I have a stock 01 Trans Am and I have only driven it a hand full of times but tonight after I beat on it a little bit, I noticed a light popping noise coming from the rear end on a sweeping low speed (20-25mph) curve. The axle did not hop nor did it feel like it was binding up. The noise was not always present in turns. The noise sounded like it was out of the left rear. I made some tighter turns but could not duplicate the noise in a tight turn. I do know the rear pinion seal is leaking but I topped off the fluid saturday for the time being. Any suggestion as to what the noise might be?
Al 95 Z28
03-22-2012, 03:59 PM
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Added the posi additive, still popping. This may be a dumb question, but arent the original springs on the eatons yellow? Why are mine purple? What other possibilities could there be for this problem?
03-22-2012, 09:26 PM
#12
The springs should not be able to add so much preload that it will pop and hammer the clutches. Who did that posi? It could be that someone shimmed the clutch packs way too tight and had to force the spider hears in palce and then buttoned it up. Can you check how much break away torque you need to apply to get the posi to slip? With posi tuning you throw away the springs and shim the posi so that the clutches just start to grab, that they are just tight when the spiders are isntalled and there is minimal if any play in the whole spider gear arrangement. If the posi then slips the gear action will force sht episder gears apart, this presses the clutch pack tighter together. The factory does not shim these things as meticulous as that so they add the preload springs. It coulv be that someone got it all too tight.
03-22-2012, 10:40 PM
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So someone potentially left the preload springs AND shimmed it to make it too tight? I bought it off a member on here who said it had a locker, possible they shimmed too tight, said screw it and tryed to pass it off to someone else? Would I be better off just buying a new posi or should i try to rebuild/ reshim it myself?
One other thing I noticed is it is MUCH quieter before the car is heated up, is it possible that it stays quiet because the gear oil is thicker cold? Could I possibly quiet it up for now by adding 140wt gear oil to the diff instead of 90wt?
One other thing I noticed is it is MUCH quieter before the car is heated up, is it possible that it stays quiet because the gear oil is thicker cold? Could I possibly quiet it up for now by adding 140wt gear oil to the diff instead of 90wt?
03-23-2012, 01:17 PM
#16
It is an auburn, not an eaton but both are the same style wet clutch type.
Didn't you notice any improvement? What oil did you initially put in it? With or without some additive?? How many bottles did you add??
Didn't you notice any improvement? What oil did you initially put in it? With or without some additive?? How many bottles did you add??
03-23-2012, 03:50 PM
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I didn't know auburn made a posi for a 12 bolt. I did notice an improvement compared to before I put the posi additive in, but it isn't as good as before I changed the fluid(before I changed the fluid, I was getting the binding when parking, now it sounds pretty much perfect until the car heats up, then it is noisy in lighter turns and a little noisey in parking). I initially put in regular 80w90 lucas gear oil, then after I was told it was a posi by you guys I added 2 bottles of the gm limited slip additive...
Should I mix a quart of 80w90 & 1 quart of 140wt with the posi additive premixed, then add two bottles of the gm stuff? I'm not sure if that could quiet it down compared to 2 quarts of the regular 80w90 with 2 bottle od limited slip additive. Or should I just quit on it now and install a new posi
Should I mix a quart of 80w90 & 1 quart of 140wt with the posi additive premixed, then add two bottles of the gm stuff? I'm not sure if that could quiet it down compared to 2 quarts of the regular 80w90 with 2 bottle od limited slip additive. Or should I just quit on it now and install a new posi
03-24-2012, 12:53 PM
#20
Don't forget to make a tight circle in both directions after you add the friction modifier. Ford's XL-3 additive works well, so does GM's 105235. Be careful with cheap auto parts store crap. Winn's is good and Mobile and others make rear end oil with it already in it.
There is an off chance that your LS unit is damaged. If the modifier doesn't cure the problem you may want to take the LS unit apart and look it over. Not that it will help a lot, parts are hard to come by.
Al 95 Z28
There is an off chance that your LS unit is damaged. If the modifier doesn't cure the problem you may want to take the LS unit apart and look it over. Not that it will help a lot, parts are hard to come by.
Al 95 Z28