Oldsproject

Looking for advice on rear end selection/change. I have a "65" Cutlass with 3:08's (non-posi). The 425/exhaust combo I put in is eating up the tires and pavement. Can a rear end be converted from non-posi to posi? It's a 10 bolt.

2blu442

Yes, you can install a posi unit in a non-posi rear but I don't know the availability of the one that would fit your 1965 Cutlass rear end. If your not concerned about original numbers it might be easier to find a newer A-body posi rear end and swap the whole thing. I understand 64-72 will fit, the 68-72 are about an inch wider, but unless you've put big meats under the car I don't think this will be a problem. 71-72 uses the corporate 8.5 10 bolts and parts are readily available. Supercars unlimited in Portland sells new Eaton posi units, I think he has both the 68-70 and 71-72 styles available. So you've got lots of options. I've got several non-posi rear ends available for the 68-72 if you decide to get a newer housing. John

joe_padavano

That axle should be a BOP 8.2". You can get parts here:

http://www.drivetrainspecialists.com...iac/index.html

Oldsproject

Thanks Joe and 2blu442, before I dive in I want to be sure I'm not getting in too far over my head.... (well I already am I guess). First things first though.

I raised the rear of the car, removed the tires and hubs. Since allot of this is new to me, this might seem as stupid questions but please bear with me.

1. While I had the car up I noticed I could turn rather easily the rear wheels even though the car was in park and the drive shaft and yoke were not moving, is this normal (boith wheels turned, oposite directions of course)?

2. I also could feel a what seemed like the gears in the rear end engaging but kind of a clicking feeling which seems somewhat normal but something is bothering me about it. It wasn't a real noticable feeling but instead of coming from the center housing felt more towards the outside ends (both) of the axle housing which makes me think that perhaps there's pitted or worn bearings or something of the sort? I may just be a bit paranoid as I read something about "64" and "65" cutlass axle bearing problems. The crux of the article was to be sure to check them as they had a tendancy to go bad and could destroy your axle. However, I can't find where I read it and perhaps it was all just a dream. Am I paranoid or is there something to be concerned about?

3. How difficult is this job IF I tackle the rear end to at least inspect the axle, bearings, gears, etc? Are there any special tools or can the usual run of the mill set accomplish the task (i.e. I don't have any way to press or remove bearings, etc.)

4. Can the job be done with the rear under the car?

I'm ready willing and able if it makes sense and with a little help from my friends.

monzaz

I can walk you through all of it and have helped may do so.

The axles can be checked in the car no problem. you just need a 9/16 socket with a extention and some muscle. remove all 4 bolts and then remove the retention plate and pull away...you should use a axle puller tool...BUT I know people just do not have these specialty tools laying around. SO, if you can get a pry bar behind the axle and brake cylinder and some other ideas like a 2x4. If you can get a couple of the backing plate bolts back on the flange with out the axle retaining plate that will give you a good sturdy place to pry against again. Then agian you may get super lucky and it will just pop out. If you car is driving and not been sitting to long it should pop out with little effort.

The diff rebuild would be alot ALOT easier out of the car.

Besides don't you want to clean the undernethof the car and paint up the control arms etc. NOW would be a great time for that.


Jim - J D Race

GM Diff specialists

CaliBoricua

Curious to know if a 67 GTO rear end fit a 65 Cutlass?
What would be the best posi rear end for a 65 cutlass? I hear aot about Eaton Posi units but I am not clear if its for rear ends that have posi or to convert a non-posi rear end?
Thanks

2blu442

Yes it will bolt up, I don't know if it has the same spring perches or not. I've been told it was mid-year 1966 when Olds went from the bolt on the rear end springs to the ones that sit on a ring. One of the diff guru's will have to comment on the best posi to use. One consideration might be if you want to keep the original style rear end underneath it, or if that's important to you. Another could be your plans for the car. Will it be a street driven car or primarily used at the race track. And also how much money do you have available for this upgrade.

I'd suggest you create a new thread to explore these ideas rather than work off this old one. John

monzaz

Yes it will bolt into the chassis with your original arms from the 65.
The bottom of the 1965 spring is a bit larger diameter than the 67-72 because they used the raise nipple for the spring to seat in. I have seen people use a rubber insulator and just use the stock 65 spring with newer 67-72 rears.

NOW something else to consider. 1967 BOP rears were 1" wider overall than your 65 66 rears with the flat perches. THE Chevy 1967 A body rears were still narrow like the 65 66. So if tire clearance is close be careful.

If you want the correct fit... them get the 67 springs too. They are a one year deal.

Jim
J D Race

CaliBoricua

I think rebuilding my rear end might be easier then replacing only because I cant seem to find an posi rear end at any of the local junk yards.
So which one of these posi trac would you recommend:

- Eaton
- Auburn
- Powertrax

I think I already have 3.73 gears but what low gear would you recommend for street and freeway use or do you think I am fine. I am not sure if the tranny has anything to do with what type of gears you can go but I have a TH350 but considering a TH400..

507OLDS

The Powertrax is a unit that installs into your existing open carrier.You would remove the spider gears & side gears,& install the Powertrax unit per the given directions.
The Auburn unit is a cone-style posi unit,pretty much just like the original posi units in those earlier rears,like the 8.2" 10-bolt BOP rears.You will need to remove your existing open carrier,remove the ring gear,& reinstall it onto the posi unit.At the least,you will need an assortment of carrier shims to reinstall the posi unit,& achieve the correct backlash.The pinion depth is not effected,if you are keeping the same gears.A new Auburn unit for the BOP 8.2" 10-bolt is $350.00,including the shipping to you,in Oregon.
The Eaton posi unit is a clutch style unit,& is also tunable & rebuildable.This would install just the the Auburn,as it is a posi carrier,not an insert,like the PowerTrax.One of these would be $450.00,including the shipping.
There are also aftermarket axles available for the 8.2" BOP 10-bolts,with better material that is less-prone to twisting & breakage.A pair of these would be $375.00 shipped,& include the a pair of axles,bearings,retainers,studs,& the seals to install into your axle tubes.

nonhog

I'm also curious about which style to use on my 12 bolt. I will have it checked out and tubes welded as well as c clip eliminators.
I will probably do 90%(or more?) street driving.
Good manners around town sounds good to me.
Cost is less important than reliability.

6 of one/half a dozen of another?

gearheads78

Go with the Eaton.

panos

I went with powertrax and im really happy with it (8,2 rear 3:36),easy to install no special oil needed and you get 100% lock when its needed! many people dont like the sound that they can make but when i installed mine it "clicked" a few times the first 10 min.or so of driving and then absolutely nothing!!! it only clicks a little when i reverse and thats it!!! i already drove it in rain and it has better manners than i thought,no problem att all.

jmo Panos

507OLDS

Eaton in the 12-bolt Chevy as well.

monzaz

The unit should still click in turns...Hoping everything is ok? Jim

That is just the way it works. NO slip will do it only one FULL rotation of the rear tire...Maybe just tight turns to the right is will be more pronounced... JIm

panos

mmm it maybe does it but its nothing that i can hear when im driving
when i put the hammer down it still lives some nice 11s on all 3 gears,so i think it works fine