10 Bolt Help
January 5th, 2011, 09:55 PM
#1
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10 Bolt Help
I looked all over this thing and could not find any numbers on the outside!!!
Can someone help to identify it from this pic and numbers from inside!!!
123477:40-13:GMC
17e0dc17.jpg
Thanks Drew
Can someone help to identify it from this pic and numbers from inside!!!
123477:40-13:GMC
17e0dc17.jpg
Thanks Drew
Last edited by Wyze; January 5th, 2011 at 10:01 PM.
January 5th, 2011, 10:07 PM
#2
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ee1164a6.jpg
Looking at the yellow paint would you say it's had some parts replaced from the junkyard??????
0b95e3e7.jpg
Looking at the yellow paint would you say it's had some parts replaced from the junkyard??????
0b95e3e7.jpg
Last edited by Wyze; January 9th, 2011 at 07:43 PM.
January 6th, 2011, 04:50 AM
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Looks like an 8.5" 10-bolt,3:08 posi. The posi unit is a cone style. This probably came from a 71-72 Buick Skylark/GS. If I saw the rest of the rear,I would know for sure.The codes that were stamped on the outside,were on the passenger side axle tube,facing the front.Look between the pumpkin,& the spring perch.As long as the tube isn't too rusty,they should still be there. You should also find a large "A" on the top of the pumpkin,and the cover is smooth,with notches at 9:00 and 3:00.
January 6th, 2011, 04:52 AM
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Not to sound like an *** but how can you tell it's a 8.2 and not 8.5??????
I heard that if it has 3/4 bolts it's a 8.5!!!!!!!
Brian I just saw you post, it maybe did come out a 72 Skylark but they weren't sure!!!!!!
I heard that if it has 3/4 bolts it's a 8.5!!!!!!!
Brian I just saw you post, it maybe did come out a 72 Skylark but they weren't sure!!!!!!
Last edited by Wyze; January 6th, 2011 at 04:56 AM.
January 6th, 2011, 06:00 AM
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The 8.5's are enlarged above & below the ring gear,for the larger gear,compared to an 8.2". The pictures are not the greatest,but everything appears to look like an 8.5".
The cone style is fine for a cruiser,but I prefer a clutch style unit for anything I build,or for anything with good power going to it.
The cone style is fine for a cruiser,but I prefer a clutch style unit for anything I build,or for anything with good power going to it.
January 6th, 2011, 06:23 AM
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10 bolt 8.5
Brian you are correct. 8.5 Bearing caps are the dead give away - Olds 12 bolt uses the same caps BUT since this has 10 bolt cover we know for sure it is not that...lol. 
Also as the other gentleman said 3/4" bolt heads (another point to 8.5). side note (69 70 71 72 pontiac 8.2 did use 3/4 headed bolts too that are reverse thread 7/16") ALso the lower 5-7 o'clock castings are there as all 8.5 rears have. CAT ears / or shark teeth I guess people call them...lol
The posi is a Borg Warner cone type...Some were used in chevy rears also then they used all trac Lock units with clutches later. This is probably a 71 because of the BW unit... Looks pretty original.
So if the rear has bolt in axles and flange to flange is 55 1/4" you have your self a Buick or Olds 71 72 A -body rear that will bolt into any 1967 -1972 BOP or 1968-1972 Chevy...with some slight drive shaft mods if the not a 71 72 cutlass or Buick skylark which obviously are a DIRECT FIT.
Great find - clean it up put some new bearings in it, check the posi and have some fun with it. JIm
Also as the other gentleman said 3/4" bolt heads (another point to 8.5). side note (69 70 71 72 pontiac 8.2 did use 3/4 headed bolts too that are reverse thread 7/16") ALso the lower 5-7 o'clock castings are there as all 8.5 rears have. CAT ears / or shark teeth I guess people call them...lol
The posi is a Borg Warner cone type...Some were used in chevy rears also then they used all trac Lock units with clutches later. This is probably a 71 because of the BW unit... Looks pretty original.
So if the rear has bolt in axles and flange to flange is 55 1/4" you have your self a Buick or Olds 71 72 A -body rear that will bolt into any 1967 -1972 BOP or 1968-1972 Chevy...with some slight drive shaft mods if the not a 71 72 cutlass or Buick skylark which obviously are a DIRECT FIT.
Great find - clean it up put some new bearings in it, check the posi and have some fun with it.
JIm
January 6th, 2011, 08:09 AM
#12
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I'd have to mod if I had a Chebbie????
Smh!!!!
Well Can I go get a Buick driveshaft????
If not, how much does it cost to shorten
What's the going rate for this rearend???
Thanks Drew!!!
Last edited by Wyze; January 6th, 2011 at 08:14 AM.
January 6th, 2011, 09:28 AM
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I'm not trying to be a pita but I'm still a little confused!!!
January 6th, 2011, 09:46 AM
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Yes,the trans doesn't matter. What is different is the 8.5" 10-bolt rear has a longer pinion snout,compared to the 12-bolt O-axle,so it needs less shaft to reach it.
Since you would be installing the rear into your 68,with a TH350,you "could" find a shaft from a 71-72 Cutlass that also had a TH350,since it would also have that 8.5" rear.Make sure it is a 2-door.
If you need the exact measurement for that particular shaft,I can get it for you,so you know what to look for.
Since you would be installing the rear into your 68,with a TH350,you "could" find a shaft from a 71-72 Cutlass that also had a TH350,since it would also have that 8.5" rear.Make sure it is a 2-door.
If you need the exact measurement for that particular shaft,I can get it for you,so you know what to look for.
January 6th, 2011, 10:23 AM
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Gotcha!!!! Now I understand!!!
I asked about a price because my buddy told me I had stole the thing for what I paid for it!!! ($250)
I just called the guy I got it from to see if he had the driveshaft!!!
He said he's pretty sure it came from a 72 Skylark!!!
Can I use that one???
I asked about a price because my buddy told me I had stole the thing for what I paid for it!!! ($250)
I just called the guy I got it from to see if he had the driveshaft!!!
He said he's pretty sure it came from a 72 Skylark!!!
Can I use that one???
Last edited by Wyze; January 6th, 2011 at 10:32 AM.
January 6th, 2011, 10:48 AM
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Can't complain about that price.Clean it up & re-bearing/seal it,and it should be good for quite awhile.If he has the shaft,and you can get it real cheap or free,get it.I don't know what length the Buicks had though.
Here is a breakdown of ALL of the bearings & seals in that rear:
Pinion,inner bearing = M802048
Pinion,inner race = M802011
Pinion,outer bearing = M88048
Pinion,outer race = M88010
Pinion seal = 2043
Carrier bearing = LM501349(need 2)
Carrier race = LM501314(need 2)
Axle bearing = SET9 or also known as A9(need 2)
Axle seal = 712146 or 2146 ***These seals have different thicknesses.Most of the A-casting 8.5's have needed the thinner 2146,but if you get the 712146,it will work.You just don't want the axle to slide in/out at all when it's all torqued in there.This is part of the job of the seal.
Ring gear bolts = 65ft-lbs with red Locktite
Carrier cap bolts = 65ft-lbs no Locktite
Here is a breakdown of ALL of the bearings & seals in that rear:
Pinion,inner bearing = M802048
Pinion,inner race = M802011
Pinion,outer bearing = M88048
Pinion,outer race = M88010
Pinion seal = 2043
Carrier bearing = LM501349(need 2)
Carrier race = LM501314(need 2)
Axle bearing = SET9 or also known as A9(need 2)
Axle seal = 712146 or 2146 ***These seals have different thicknesses.Most of the A-casting 8.5's have needed the thinner 2146,but if you get the 712146,it will work.You just don't want the axle to slide in/out at all when it's all torqued in there.This is part of the job of the seal.
Ring gear bolts = 65ft-lbs with red Locktite
Carrier cap bolts = 65ft-lbs no Locktite
January 6th, 2011, 03:32 PM
#22
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I was just going by the shape of the gasket that was on the housing.
1971 GS diff cover gasket in the first pic 8.5
1968 GTO diff cover gasket in the second pic 8.2
I did say it was a guess but after hours of searching online, I still can't find a pic of an 8.5 that takes the pic 2 gasket.
1971 GS diff cover gasket in the first pic 8.5
1968 GTO diff cover gasket in the second pic 8.2
I did say it was a guess but after hours of searching online, I still can't find a pic of an 8.5 that takes the pic 2 gasket.
Last edited by InfoJunkie; January 6th, 2011 at 05:27 PM.
January 6th, 2011, 06:53 PM
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10 bolts
The 10 bolt 8.5 1971 72 73 74 Buick olds Pontiac rears have the same scalloped LOOKING <--- stress on the LOOKING...because they are NOT the same as the 8.2 10 bolt cover in bolt hole pattern.
EASE way to tell the difference in the 8.5 cover and the 8.2 cover with the scalloped cover is -
10 bolt 8.2 cover has a cut in the top of the rim edge of the cover 12 o'clock bolt for the chassis brake hose bracket to mount about a 1/2" cut.
The 10 bolt 8.5 does not and has little rim bulges at the 12 and 6 oclock rim edge. ALSO the 8.5 has a boss at the top of the cast housing inbetween the upper control arm ears where the chassis hose mounts. It is taped for a 5/16 bolt.
That is it... now everyone should have very good info to ID the 8.5 from a 8.2. Jim
EASE way to tell the difference in the 8.5 cover and the 8.2 cover with the scalloped cover is -
10 bolt 8.2 cover has a cut in the top of the rim edge of the cover 12 o'clock bolt for the chassis brake hose bracket to mount about a 1/2" cut.
The 10 bolt 8.5 does not and has little rim bulges at the 12 and 6 oclock rim edge. ALSO the 8.5 has a boss at the top of the cast housing inbetween the upper control arm ears where the chassis hose mounts. It is taped for a 5/16 bolt.
That is it... now everyone should have very good info to ID the 8.5 from a 8.2.
Jim
January 6th, 2011, 06:57 PM
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10 bolt 8.5
all 8.5 UNITS ARE INTERCHANGEABLE eVEN THE 30 SPLINE 8.5 UNITS FROM 1990 -1996 WILL FIT THE HOUSING. Even the truck units will fit the 1971 housing. 8.5 is 8.5 .
YES-
This rear is 28 spline so you should make certain the aftermarket auburn unit is 28 spline.
YES-
This rear is 28 spline so you should make certain the aftermarket auburn unit is 28 spline.
January 6th, 2011, 07:07 PM
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posi
WELL the best way is always to unbolt the unit and disassemble it to see how close the cones are to the bottom of each 1/2 they wear into. IF you see any shiny spots on any of the flat surfaces NOT the conical area that will look scarred (normal)
If the bottom of the cone 90degree surface or tower in the bottom of the case is rubbed shiny then the cone has bottomed out and the posi is worn out. We can machine the cones and reshim the unit to work again but it will only be a fix and we never know how much life is given back. I have done many and keep checking back with customers to see how they are running - 2 years on one so far pretty hard spirited driving.
again reference pictures.
red arrows show where the cone bottoms out in the case- This is a newer auburn unit and will be slightly different from yours inside but it will be roughly the same deal. Jim
If the bottom of the cone 90degree surface or tower in the bottom of the case is rubbed shiny then the cone has bottomed out and the posi is worn out. We can machine the cones and reshim the unit to work again but it will only be a fix and we never know how much life is given back. I have done many and keep checking back with customers to see how they are running - 2 years on one so far pretty hard spirited driving.
again reference pictures.
red arrows show where the cone bottoms out in the case- This is a newer auburn unit and will be slightly different from yours inside but it will be roughly the same deal. Jim
Last edited by monzaz; January 6th, 2011 at 07:10 PM.
January 7th, 2011, 12:07 PM
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pictures
Yah the picture say so much more than words ever do. I love that feature on the sites cause trying to explain and then terms from one person to the next differ etc. :0 Good luck on the rear.
January 9th, 2011, 11:14 AM
#32
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The driveshaft that you will need,for a 68-72 Cutlass,with a TH350 transmission,and the 8.5" 10-bolt rear,is 55" from center of u-joint to center of u-joint.
Another note: The A-casting 8.5" 10-bolt,which are the ones with the notched cover that look like the BOP 8.2",originally came with the squiggly gasket,and the O-casting 8.5" 10-bolts,with the round cover with the protruding rib from 12:00 to 3:00,came with the wider/solid gasket.
Another note: The A-casting 8.5" 10-bolt,which are the ones with the notched cover that look like the BOP 8.2",originally came with the squiggly gasket,and the O-casting 8.5" 10-bolts,with the round cover with the protruding rib from 12:00 to 3:00,came with the wider/solid gasket.
January 9th, 2011, 12:07 PM
#33
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Bad news!!!!
I was just trying to clean oil out the rearend and found some metal inside of it!!!
Smh!!!!
I couldn't see it at first but I do now!!!!!
I've heard that's a very bad sign!!! Just my luck!!!!
I'll get pics after I warm up and go back out in the garage!!!!!
I'm pissed!!!!!!!!
I was just trying to clean oil out the rearend and found some metal inside of it!!!
Smh!!!!
I couldn't see it at first but I do now!!!!!
I've heard that's a very bad sign!!! Just my luck!!!!
I'll get pics after I warm up and go back out in the garage!!!!!
I'm pissed!!!!!!!!
January 10th, 2011, 05:25 AM
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ring gear
Well the ring gear appears to be in good condition sop I am sure the pinion is fine also.
POsi you will never know until you remove the unit and tear it apart. You can do a inthe rear torque test but it is unreliable at BEST.
There is always going to be some metallic silt if you have large sharpe shaving or chunks YAH you could have an issue. Best thing is to take a gallon of kerosene and pour it in after you let the rear drain upside down for a day 2 days if your in the COLD weather states....LOL. Jim
Pour the kero in after and get a brush clean it the best you can turn the pinion round and feel how much grit you have... after you think you got the OLD oil broken down enough dump the kero into a seperate pan from your oil so you can still use some of the fluid for cleaning after you remover the carrier too. OF if you have plenty of clean just pitch it and use new. Jim
clean clean clean....
POsi you will never know until you remove the unit and tear it apart. You can do a inthe rear torque test but it is unreliable at BEST.
There is always going to be some metallic silt if you have large sharpe shaving or chunks YAH you could have an issue. Best thing is to take a gallon of kerosene and pour it in after you let the rear drain upside down for a day 2 days if your in the COLD weather states....LOL. Jim
Pour the kero in after and get a brush clean it the best you can turn the pinion round and feel how much grit you have... after you think you got the OLD oil broken down enough dump the kero into a seperate pan from your oil so you can still use some of the fluid for cleaning after you remover the carrier too. OF if you have plenty of clean just pitch it and use new. Jim
clean clean clean....
January 10th, 2011, 06:11 AM
#40
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Lol!!! Yeah we posed to get 2-5" of snow today so it'll prob be a couple of days!!! Smh!!!
I'll keep you posted!!!
I was thinking that guy might have known those metal chunks were in there!!!!
My reason for saying that is how easy the cover came off & the price he sold it for ($250)!!!!!
I'll keep you posted!!!
I was thinking that guy might have known those metal chunks were in there!!!!
My reason for saying that is how easy the cover came off & the price he sold it for ($250)!!!!!
