I've found a GM 10 bolt that should work great under my '52 chevy pickup project. Its the right width and the axle perches line up with the original pu springs. It came out of a 67 firebird convertable, 400, powerglide. I was under the impression that all gm 10 & 12 bolts were C clip axles, this one has press on bearings. Is this a good find or is this going to be some oddball thats hard to find parts for?
Olds Cutlasses, etc. around the early '70's had the axle bearings retained by plates just like Fords. The gears were odd sized so any hop up stuff probably won't work, but it will work as is if you like the ratio.
It's a Buick, Olds, Pontiac 8.2" 10 bolt. Bolt in axles. I always thought that they had to be a least a "little" better than the Chev C-clip 10 bolts. Summit carries one or two gearsets yet(I think), and Auburn makes a limited slip unit for them. My cousin runs one in his 12 second Grand Prix with a mini-spool. Its no 12 bolt, but if its the width you need, I'd run it.
i've got one in my 69 camaro. came out of a 68 firebird 400,great rearend, mine has the factory inboard traction bars that work real good. i'm running mine behind a 427 and a muncie 4 speed and (knock on wood) have had no problems in the 10 plus years i've been running it
Thanks for the info, I feel a lot better about this axle now. The gear ratio is 2.56:1, highway gears, but I think it will work for now. Now if I can only find a running 261 chevy inline six that I can get dirt cheap and isn't a thousand miles away
If it's a posi, you can usually repair them by sanding the "cones" inside the rearend with emery on a piece of glass or some level surface. It's an old trick showed to me by a fellow mechanic back in the 70's...Last one I did was for a black 67 Firebird 10 bolt. Got that old poncho hookin up with both rear tires for as far as you cared to smoke the tires...400, 4 speed. That weekend, the owner oversmoked and totalled the car!
10 bolt chevys are pretty strong if built right, i have one behind my big block, came stock with the car in 67... eventhough there is some play when you yank the rear wheel, its withstood alot of abuse..
I put a 69 Firebird unit under my 35 Buick. With a 390 Cad and hydro it never once gave a problem in about 4 years of driving all over the East and Midwest. Best part was the width was perfect and just had to move the spring perches a bit.
Lots of great info. I did buy the rearend and have easily found parts for it. within about 5 minutes of looking I found a variety of gears 3.36, 3.55, 3.73, 4.11, and 4.56 are all available as well as posi units. A hopped up 235 inline 6, T5 trans, and this rear should get me anywhere I need to go. Oh, and he threw in a rear sway bar for it too.
i know that this is an old thread but i'm trying to remove the axles from a 10 bolt posi that was removed from a '66 buick skylark. I have the cover off and all the bolts that mount the backing plates and the flange that holds the axle to the rear end housing assembly. I cannot pull the axles out. Not sure whats holding them in place. Any ideas what to look for behind the carrier?... Maybe a limited slip?... Any help would be greatly appreciated.
hook a slide hammer to the lug studs and give it a few good pulls. They get stuck. 66 Should be the BOP rearend. Does the cover have a small semi circle on each side like the pic below?
how are you pulling the axles?...slid hammer?...if the axles have a flange and bolts @ the backing plate then no C clips....A 2' length of logging chain hooked to a lug nut and snapped back will usually do the trick...used to do it every weekend when I put 4.56 third member in my '56 chevy street/drag car. good luck
Many 8.5 10 bolt rears are non c clip.Far as I understand all 10 bolt 8.5's have interchangable carrier gears .Quite rugged ,some say as good or better than a stock Ford 9 inch or stock 12 bolt GM.The earlier 8.2 10 bolt isn't as strong. On a 8.5 inch 10 bolt,the carrier break is 2.73,meaning 2.73 higher numerical gears will fit .A 2.56 gear carrier needs special gears or spacers for 2.73 and up gears.
thank you so much guys yes my diff cover looks the same as the pic. how do you know the difference between a limited slip and a posi dont know what i have???
just got the axles out of the rear thanks for the help. next question is how do i get the bearing and collar off of the axle? are they pressed on to the axle?
You hit one of my peeves with this. "Limited Slip" is a posi. So is a "Traction Lock" or a "Sure Grip" or a "Detroit Locker". All are positraction units. A non posi is an "open" differential. Most of the names used were trademarks or marketing names for their optional axles. If you can clearly see the differential gears, no springs, no inner housing (best way to describe it) it's an open rear gear set.
Once again a slide hammer will do the trick. They make a tool that works nifty on bearings and seals. I'd go to autozone and get a free loaner. Yes they are pressed on the axle tubes.
If no slide hammer available, this trick works well. Make sure the jackstands are placed securely, unbolt the retaining ring then put the brake drum on the studs backwards. Put the lug nuts on several turns, make sure that they're pretty much at the same depth, leaving a couple inches play. Grab the drum firmly, pus it back to the flange and use it as a slide hammer. Worked as a mechanic at an Oldsmobile dealership in the late 70's, when they had the big recall on Cutlass axles. Took literally hundreds of them out this way.
Hold on- let's clarify a little. The only 8.5" ten bolt that was non C-clipped was the 71-72 Buick and Olds A body unit(Skylark and Cutlass). The Pontiac A body still used a Pontiac 8.2" ten bolt, and the Chevy A body used a Chevy 8.2" ten bolt. The units are not the same. The Chevy was a weaker rear with C-clips, smaller axles, smaller spline count, and a small pinion. The Pontiac had larger bolt in axles w/ a higher spline count and a larger pinion gear. The Camaro used a Chevy 8.2" ten bolt from '67 until the switch to the 8.5" Corporate ten bolt w/ C-clips in the very early 70's. The Firebird used a Pontiac 8.2" ten bolt (the same as the LeMans/GTO, just set up for leaf springs) from 67 until 70. Then a switch was made to the 8.5" Corporate 10 bolt w/ C-clips. The 8.5" C-clip rear is a good piece, I just don't care for the C-clip axle retention. NOTE- the above info EXCLUDES the performance cars (GTO, Trans Am, SS Chevelle, SS Camaro, etc.) that used a 12 bolt when it was available.
Absolutely! Thank you for stating this. I hear guys tell me they have a limited slip for sale. I show up and it's an open diff. Posi-traction was Chevy's name for a limited slip differential.
Just to clarify a little Detroit Locker, EZ Locker, Aussie, lunch box style, ect are automatic type locking diffs. Detroit True Trac is a LSD. Not to many Non 4x4 guys run a Detroit or automatic style unless it's a track only car in which case they probably run a spool. I just found this thread searching for info about a 10 bolt under my '80 Trans Am. The axle is a non c clip with 28 spliners. It has a regular 10 bolt cover with the swoosh in the top (not like the cover on page 1). What is throwing me off is that it has the upper control arm mounts cast in the diff and small coil buckets with my leaf/shock mounts boogered on. I think I've got a bent shaft because when in drive on the lift the wheel goes caddywampuss. This could've been caused by my engine blowing up violently 10 feet from the traps at the track or by me just beating the crap out of it. Thinking I had a Monte Carlo rear, I found one on the local list for $50. Pulled the 28 spline c clipers, got new non tapered bearings and seals. When I went to pull the shafts out of my car, I see they're non c clip style. Now I'm back to thinking I've got an 8.2. It's a stock style posi with s clips and clutches and 4.56 gears. My question is do the 71-72 Buick and Olds 8.5's have coils and upper control arm mounts. If so I hope that's what I've got because it seems to be the best and strongest 10 bolt. C clips make me nervous with 489hp and the possibility that if broken my wheel could fly off. Thanks
And a TrueTrac is a gear driven, torque biasing limited slip at that (ala, Torsen). Hard to place that in the same category as a clutch-style limited slip (ala, Positraction, Trac-Lock, Powr-Lock, etc.), but there it is. This is a pet peeve of mine. Maybe we can subdivide that category into active v.s. passive limited-slip. One uses a clever array of gears to transfer torque to the wheel that has the most traction, the other just makes it really difficult for the axle shafts to turn out of sequence with the carrier.
Ahh yes, more clarity. Dig it. I'm more familiar with the popping and banging of the automatic types and the selectable and mighty ARB air locker, which I've run 3 going on a 4th in my jeep(stock 30/44 now 60/14bt). These 10 bolts are kinda new to me. Just wait 'til I get to the banjo in my '29 and that Columbia 2 speed if I can get him to sell
Just a little experience with the GM 8.5 corporate rearend I have had..... DO NOT use them in a dirt track car. The bearings do not hold up very well under a side load for too long. Just thought the info might be of use to someone out there.-Weeks
i put a 12 bolt in a tbucket and pulled the cover to install a chrome cover and it would not fit(different bolt pattern)come to find out it is a olds 442 rear end.first one i've seen.12 bolt,full floater.looks like 12 bolt chevy car but different.o well
First of all, that is not a 12-bolt and you got ripped off if you paid big dollars for it. You have a Type O axle, used only in the Cutlass/442 cars from 1967-1970. It has 12 bolts on the cover but only ten bolts holding an 8.5" ring gear. A real Chevy 12 bolt has 12 bolts holding an 8.875" ring gear. Parts for the Type O are very hard to find and "corporate" 8.5" parts don't fit. The "12 bolt" refers to the number of bolts holding the ring gear, not the rear cover. It is only coincidence that the Chevy 10 bolt and 12 bolt axles use the same number of bolts on the ring gear and on the cover. Other GM axles do not, as you have found out. Also, the Type O is not a "full floater". That refers to the type of axles used on one ton trucks where you can pull the axle shaft out of the housing with the hub and wheel still in place. The Type O uses the same type of axle shaft bearing design as any other car axle. The difference is that the bearings are pressed onto the axle shaft and retained into the housing with a plate, so no C-clips are required. This is the factory version of the "Olds axle ends" that everybody welds onto Chevy axles.
I plan to reduce the rear temp. It is not necessary for the high efficient pump setup because I am not racing this vehicle. How much (percentage) will the aluminum cover reduce the temp? What cover options would you recommend? It would seems that most any cover will do the job with minimal differences depending on the design (heat sink fins or smooth). Thanks,
<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <wunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]-->I think I found some useful information on aluminum differential covers. After market covers with increase the fluid capacity can run 15 to 20 degrees cooler. The following URLs may help. http://www.mag-hytec.com/differential.htm and http://www.drivetrain.com/parts_catalog/accessories/differential_covers.html They cost in the range of $200 - $300.
The Jalopy Journal
