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Another broken 12 bolt thread

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Old May 3, 2007 | 10:16 PM
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Unhappy Another broken 12 bolt thread

ok.... i have a strange 12 bolt with 4:10's 33 spline axles lpw cover and posi. i broke it in as reccomended and used 2 quarts of vlavoline non synthertic 80w 90 gear oil + 2 bottles of gm posi additive. i have the heavy duty crossbrace mounted spohn adj. torque arm with driveshaft loop also. the 12 bolt just hit 1800 miles and it has always whined a little. lastnight i drove over a large bump and even at an extreme angle tryin to aviod it, the crossbrace bottomed out pretty hard. right after that i noticed it was whining somewhat louder. i parked it for a couple hours then drove home. when i left the parking lot it was making a LOUD grinding noise at slow speed. on the way to the house i babied it and it progrssively got louder and i noticed some vibration. i started to panic about this time.... when i would acellerate the noise would die down but when i let off it came back LOUD. i took the cover off today and checked the gears. they look fine to me but there were some very fine metal shavings on the magnet drain plug. i noticed alot of oil under it and some drops building up around the pinion seal and splatters all on the undercairrage. could the torque arm have gotten knocked out of alingnment and fucked up the pinion angle then proceed to **** up the pinion seal/bearing?

What could this be!!?! should i give up and just have it checked out and possibly rebuilt? some one please help! the car will not move untill this is solved
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Old May 5, 2007 | 06:47 PM
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I'd put your car on jack stands and check out the underside, maybe something is hitting the floorpan. Are you sure the pinion seal wasn't leaking prior to this? Bob
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Old May 5, 2007 | 07:16 PM
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its up on stands right now, it wasnt leaking any to my knowlege. it did leak out of the bottom bolt hole on the rear cover tho. now the pinion seal leaks pretty good, im sure its the pinion seal and possible the bearing since there were metal shavings on the drain plug
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Old May 5, 2007 | 07:30 PM
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sell it and get a 9 inch
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Old May 5, 2007 | 07:33 PM
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Originally Posted by 1nastyss
sell it and get a 9 inch
Ditto. 60's/70's Muscle cars = 12 Bolt, 4th Gens = 9 inch!
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Old May 5, 2007 | 08:08 PM
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Originally Posted by westxwitesnake05
its up on stands right now, it wasnt leaking any to my knowlege. it did leak out of the bottom bolt hole on the rear cover tho. now the pinion seal leaks pretty good, im sure its the pinion seal and possible the bearing since there were metal shavings on the drain plug
Shavings on the drain plug are pretty common, as new gears become broken in. Does the torque arm look damaged? Bob
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Old May 6, 2007 | 09:12 AM
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I have a Strange 12 bolt just like yours. Whines loud as sh*t but isn't broken. You bottomed out and probably messed up the pinion angle on the torque arm or something.
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Old May 6, 2007 | 08:31 PM
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Bob - yeah the torque arm is all scraped up and the tubing is bent in slightly at the cross brace but i dont think it would throw off the P/A enough to blow the pinion seal? the 2 pivot blots were also pretty lose

i checked the angle with a dgreewheel and it was -9 on the driveshaft yoke and -6 on the rear end. of course the car isnt perfectly level and i belive to correctly measure the p/a you have to remove the driveshaft and check the degree on the yokes? i found good writeup on measuring p/a on here i just need to read it.

i was thinking about gettin a diffrent torque arm that mounts to the trans. i wasnt sure if i should do that or not cause i will hopefully have a stroker in the future and dont want to have all that stress on the trans. what is the maximum rwhp/tq a trans mounted t/a could take? also should i get an adjustible one or non ajustible? i was lookin at a UMI non adjustible t/a

also how hard is it to replace the pinion seal and bearing?

thanks for all the help fellas

Last edited by westxwitesnake05; May 6, 2007 at 11:34 PM.
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Old May 7, 2007 | 04:31 AM
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It does not sound like you broke it with power, it sounds like you broke it by slamming it into a speed bump. Just kinda misleading with the thread topic.
Your cardomain page says something to the effect of "F--- ground clearance"
Perhaps you should rethink that philosophy.
Not trying to be a dick, I know I sound like one but it sounds like you need some ground clearance.
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Old May 7, 2007 | 05:03 AM
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Originally Posted by westxwitesnake05
Bob - yeah the torque arm is all scraped up and the tubing is bent in slightly at the cross brace but i dont think it would throw off the P/A enough to blow the pinion seal? the 2 pivot blots were also pretty lose

i checked the angle with a dgreewheel and it was -9 on the driveshaft yoke and -6 on the rear end. of course the car isnt perfectly level and i belive to correctly measure the p/a you have to remove the driveshaft and check the degree on the yokes? i found good writeup on measuring p/a on here i just need to read it.

i was thinking about gettin a diffrent torque arm that mounts to the trans. i wasnt sure if i should do that or not cause i will hopefully have a stroker in the future and dont want to have all that stress on the trans. what is the maximum rwhp/tq a trans mounted t/a could take? also should i get an adjustible one or non ajustible? i was lookin at a UMI non adjustible t/a

also how hard is it to replace the pinion seal and bearing?

thanks for all the help fellas

I wouldn't go to a tranny mounted torque arm. The BMR trac pak, pn# TPU001 gives you much better ground clearance.
http://www.exoticperformanceplus.com....html?item=171

You will want to replace the crush sleeve when replacing the pinion seal. It is not an easy job if you are not familar with the internals of rear-ends. A google search could probably come up with the procedure though. Bob
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Old May 7, 2007 | 08:30 AM
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Originally Posted by revtime
It does not sound like you broke it with power, it sounds like you broke it by slamming it into a speed bump. Just kinda misleading with the thread topic.
Your cardomain page says something to the effect of "F--- ground clearance"
Perhaps you should rethink that philosophy.
Not trying to be a dick, I know I sound like one but it sounds like you need some ground clearance.

i know i did not break it with power. And youre right, i do need the clearance. i am going to get rid of this torque arm no matter what since it is what caused all my clearance issues. so if i get something that doesnt hang so damn low i was thinking of slightly lowering the car later on. sorry for the misleading title. i thought it would be the last thing on my car to break... but thats my luck
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Old May 7, 2007 | 11:39 AM
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Originally Posted by Exotic Performance Plus
I wouldn't go to a tranny mounted torque arm. The BMR trac pak, pn# TPU001 gives you much better ground clearance.
http://www.exoticperformanceplus.com....html?item=171
Actually our transmission mounted torque arms will not effect ground clearance at all. When you go with a tunnel mounted set-up like that and ours too then yes they can reduce ground clearance.

Hope that helps,
Ryan
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Old May 7, 2007 | 05:37 PM
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Originally Posted by Exotic Performance Plus
I wouldn't go to a tranny mounted torque arm. The BMR trac pak, pn# TPU001 gives you much better ground clearance.
http://www.exoticperformanceplus.com....html?item=171

You will want to replace the crush sleeve when replacing the pinion seal. It is not an easy job if you are not familar with the internals of rear-ends. A google search could probably come up with the procedure though. Bob

man that trak pak looks like a flimsy lil piece of crap compared to the one i have now the only problem with the spohn is it just hangs way to low. my exhaust has plenty of room. hell i could just build my own cross brace and tie it into the subframe like the trak pak. i bet i could make one with alot better ground clearance. just a thought.

thanks for all the help guys
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