Hi all! I have a 1970 Skylark Custom with a 350 2bbl, TH350 and 10-bolt 8.2" open diff. Recently the cross pin snapped right off and the spider gears were thrown around inside the diff damaging the other gears. Not a big deal because I wanted to fit a posi diff anyway. I did read some of the other threads here, saying that there are not many options to go for with my 10 bolt 8.2" axle, and getting a 8.5"axle is a good option. However, I do find some posi units that I believe willfit in my original axle: http://www.taperformance.com/proddetail.asp?prod=TA_1780-C http://www.summitracing.com/parts/etn-19674-010 Will these fit? If I can reuse the original axle, that would be the best. Not 100% sure which gears to go for, but I'm thinking 3.55 or 3.73 ratio. Most of the time I will cruise slowly through town, with the occasional burnout, but I will also do some highway driving (50mph) from time to time. Not very far though, like 120 miles or so. I would like to fit some gears that would help enhance the responsiveness and perceived power of the car, and that's more important than keeping highway rpms low. I do have some future plans for the engine as well, so I would like to fit gears that match.Although I'm a calm and behaved driver, an american muscle car for me should be able to do a burnout from stand still. Without power braking! So this will be my goal, to be able to smoke those tires when the green light hits. Sorry if I sound like a savage, this kind of driving will be the exception. Its more knowing that you can, rather than doing it. This thread should focus on the gears, but I do believe that considering the other upgrades are important to choosing the right gears. I'm thinking of fitting a new cam,something like this maybe: http://www.taperformance.com/proddetail.asp?prod=TA_284-88H-350 As well as a new carb and intake: http://www.taperformance.com/proddetail.asp?prod=TA_1235P Not sure if these upgrades are the best or alone will give the power to burnout, but I don't want my rear gears to limit future upgrades if you know what I mean. Additionally I probably need some kind of installation kit for my new posi unit? Like shims and bearings and stuff? Not sure what would fit there? Hope someone can give their opinion and help me in the right direction! I need to be sure before ordering, because shipping and import taxes to Norway is not a joke. I just cant wait to have my skylark back on the road as summer is approaching! Pic of my axle: Thank you!
The T/A unit will fit, and it's a good one. I think the only gear choices you will have are 3.42 or 3.64 and the the 3.64's are hard to find...Both are expensive.For the driving you describe, I'd say the 3.42 is a great gear....I've got it in two of my cars, and I like the ratio alot. Look in the parts for sale section, and you'll find someone who is having a run of them done from Fabcraft, and T/A may have them as well.... I will say by the time you buy all the parts for the 8.2, you'll be at the price of a totally rebuilt 8.5 with a 71-72 driveshaft, which is arguably a better axle, or at least much cheaper and easier to get parts for. Carhex, Mr Skylark or Everyday Performance can hook you up and ship quick and easily.
There are two gear ratios available from FabCraft,in Texas. They are 3:42 & 3:64. About $475.00/set. The posi unit is the easier part,as there are a few different types available that will fit.
There is only One posi unit for the 3.42 or 3.64 Fabraft gears. It is a Modified Auburn unit I have modified other units to provide posi units for 2.56 2.73 2.93 also. I can also build you a custom 3.64 -5.00 posi unit also But will be pretty expensive... Rebuild kit is not a problem at all I have all the kits instock on the shelf BIG thing you need to worry about before beginning to think about rebuilding the rear... IS the rear a GS rear with the 68 69 sealed bearing? IF yes YOU MUST find RW507GR first...If the rear needs axle bearings. IF you can not find these STOP... That will be a BIG hurdle to over come. Everything else is just MONEY. Jim J D
Thank youall for your opinions! It's hard for a beginner to find the right stuff in thisjungle of parts! Thanks for taking your time. So if Iunderstand you correctly, this gear won't fit the TA-posi unit and my 8.2"axle? I can't see why, but I believe you. http://www.summitracing.com/dom/parts/mgr-bp882355/overview/ I totallyagree with your arguments on the rebuilt 8.5" axle, it seems like thebetter choice for the future. The reason I was looking for replacement parts to my 8.2"axle, is to eliminate some additional factors. I know that the 8.2" axlealready fits in the car, the drive shaft fits, the wheels, brakes, suspensionand everything fits. I live far away, so I really need things to fit the firsttime. But, you guys know what fits and what has to be done, so if you help meunderstand, I will for sure consider the rebuilt 8.5" axle. In addition,shortening the drive shaft might cost another $500-600 in Norway, so I need tokeep that in mind as well. Are there anything else I need to worry aboutregarding the 8.5" axle? Will it bolt right on to my '70 skylark? By theway, I'm not steady in all the terms, do you have different names for the shaftbetween the gearbox and the diff. And the diff. And the wheel? It is the shaftbetween the gearbox and the diff that needs to be shortened, right? Jim: howcan I check if I have the GS rear with sealed bearing? Is this bearing for thepinion gear? How much would it cost for you to supply everything I need for a3.42 posi rebuild, assuming I don't need the sealed bearing?
I haVE NOTseen any pictures of your differential ....So I can not tell you what will or will not fit. Jim J D
The ONLY thing you would need to modify,if swapping a 71-72 8.5" 10-bolt into 70 Skylark,is the driveshaft. Everything else is the same. As far as the the original 8.2" Buick rears that came in those,I use the 8.5" 10-bolt posi units in them. The 8.2" Buick and 8.5" have the same inner diameter on the ring gear,which is 4.995". They also have the same bolt circle on the ring gear,6.125". Same 7/16 bolt holes,so the ring gear is a direct bolt-on. Yes,the Buick has two different bore diameters for the carrier,but they are a common size for other rears,as well as the 8.5". All of the new 8.5" carriers have the larger bearing hub,so you install the SET 36 bearing on the driver's side,just as the factory did,and for the passenger side,you install the LM102949 bearing & LM102911 race,which is what you use when you install any of these new carriers in the older 8.5's.No special machining voodoo needed. I'm doing a 70 3:42 now,and will be doing another 70 3:64 in the future,but I will be upgrading that one with 30-spline axles.
Jim: so you even have variations of the '70 8.2" 10-bolt axles? Would you need a picture of the serial number on the axle or somthing like that? I'm sorry if I'm slow to get it, but this is all new stuff to me. I'm learning, so please bear with me. Brian: what you are saying about the use of 8.5" parts in the 8.2" axle is interesting. Why do you prefer the 8.5" parts? Is it because of the price, availability or selection? Won't the 8.5" ring gear be to large for the 8.2" housing? I'm probably wrong again, but in that case, would this 8.5", 10-bolt, 28-spline posi unit fit? http://www.summitracing.com/int/parts/etn-19557-010/overview/ I see they mention the same bearings. If it doesn't fit, do you have a link to an example unit? Thank you all!
You don't and can't use the 8.5" gears.Only the Buick gears will work,and FabCraft is the only one making them. I use the 8.5" posi units because they are a lot more common,cost less,and you have a wide selection to choose from. I don't care to use an overpriced Auburn.
Ok, I'm beginning to get the picture. I've been talking to some friends of mine with mechanical background, and they all encourage me to go for a complete rebuilt axle. Apparently it's not straight forward to set up those new gears, and there's a risk of damaging something if its not done right. The parts alone would be somewhere around $1200 + shipping and local tax. I think I saw somewhere here on the forum that a rebuilt 8.5" posi axle is about the same? I've also got hold of a dude who will shorten my driveshaft for a case of beer, so that's nice. The one big concern that I have is the shipping cost of a complete axle to Norway.. Has anyone here shipped stuff like that to Europe before, and have an idea of shipping method and cost? Thank you all for your inputs guys!
I have shipped rearends to Holland,Sweden twice,and Australia. They were all shipped to either a dock on the east coast or California.At this point they were put in a large shipping container and shipped by boat to that country. I was only responsible for getting it to the dock,where the container was.My customers had made the arrangements after they were placed in the container.
Check your local Car guy forums.... There are ALWAYS guys wanting to fill containers as fast as possible... Local restoration shops may have a USA connection with a container. Trust me there is someone in Norway wanting to complete the container. Jim
I've been looking for some containers to join, but so far no luck. I will keep looking. In the meantime I have gotten hold of a dude who can help install new parts in my 8.2", and currently that seems cheaper and a lot faster. I contacted summit racing, and they told me these parts would fit my axle. I'm a bit worried about the 3.55 gears, didn't you say they were only available in 3.42 and 3.64 for the 8.2" axle? a) Positraction Differential: http://www.summitracing.com/<wbr>nv/parts/etn-19674-010 b) Ring and Pinion Set: http://www.summitracing.com/<wbr>nv/parts/rmg-4900821/ c) Complete Installation Kit: http://www.summitracing.com/<wbr>nv/parts/rmg-8310401/ Would these parts fit my axle, or would I just end up with heavy and expensive paper weights? Thanks!
See post #9 again. The 64-67 BOP 8.2 rear IS NOT THE SAME as the 68-70 8.2 10 bolt BUICK rear. Sumitt does not know this. Lots of people make that mistake. You can't afford to do that given your location. A minor inconvenience for someone here is a big problem for you. http://jdrace.com/diff_id/10bBOP_Early.htm http://jdrace.com/diff_id/10bBOP_Pontiac.htm is not the same as the Buick 68-70 8.2 10 bolt http://jdrace.com/diff_id/10bBOP_Buick.htm Look at the differences.
Hi all, time for an update. Got a shipment of parts from Jim @ JDrace a couple of days ago, so the rebuild process can start. 3.42 gears, limited slip differential and rebuild kit + wheel bearings. Removed the rear axle yesterday, so I'll start disassembly and cleaning this weekend. Not gonna rush this rebuild, as it's the first time I do something like this.
Hi guys, Grinded down the rust and disassmebled the axle yesterday, but stoped after removing the pinion gear because I wasn't sure how to proceed. I assume this is the new seal? It looks a bit different that the old one, but I bet it will fit inside the housing. Can i just remove the old seal with whatever means? How about the inside? The shiny metal ring behind the race here prevents me from tapping out the race from the outside of the axle. What do I do with that? Do I need to save it for later use? The race is pretty snug in there, so not sure if I can pull it out. Thanks!
The OIL SLING...As it is called...MAY not be totally necessary...BUT the thickness of the item under the race will make a difference if you remove this item. SO. You should be able to take a punch from the back side (yoke outer pinion bearing hole) and drive it outwith the race. IF you have a round socket (BIG) you can use that so as not to mangle the sling... Nothing is super easy so take your time and in the end it will save you headache in the long run. IF you mangle it beyond reuseableness <<< (real word? lol) measure how thick it is and try to get shim material behind the race OR you can put it under the pinion shim area as you reset the new gears. ...Ok? Hope this helped... This is what my web site for... Jim
