What better than to come to you guys?

I can get my hands on a v6, for parts purposes mind you... the one I'm looking at has a stick with 3.42 and posi and drums. Does anyone here know much about these options?

I'm thinking of changing out the differential and need to know the specs on that rear, spline, carrier etc if the differentials are compatible.

 

It's got a posi? Sure about that? As far as I knew, no v6 came with a posi.

But why swap the gears and axle and etc out? Just put the whole friggin' axle under your car! The v6 gears/axles weren't weaker than what came under a v8, it's the same axle assembly. I take it you have rear drums now? You've got a simple swap... remove your axle, install the v6's axle, then bleed the brakes.

'Course, I'm known for complicating things... you could rebuild the axle while you've got it out of the parts car. I put a 3.73/posi/disc axle from an '84 trans am under my car. (Then the posi blew up and I had to get a junkyard axle for $100, still gotta fix the 3.73 one, dammit.) I painted the axle with http://www.por-15.com 's Super Starter Kit, in semi-gloss black. I replaced the rear axle shaft bearings- these are commonly "misnamed" as rear wheel bearings- and the rear grease seals. I rebuilt the rear brake system... originally I rebuilt one rear caliper, and the other was too rusty inside to rebuild, so I traded it in as a core for one that was already rebuilt. Turned out GM had a recall out on the 82-88 rear calipers, so I took 'em off again, and rebuilt 'em myself with the GM recall kit.

One thing you should know first before pulling the axleshafts to change the rear bearings/seals- you've gotta remove a pinion shaft lock bolt, to remove the pinion shaft, to remove the c-clips, to remove the axleshafts from the car. Those lock bolts like to snap in half, leaving the pinion shaft locked in to the differential, and it's a bitch to remove. So you might not want to risk it!! I snapped the one on my original v6 axle, and had to buy the junkyard axle when my 3.73/posi/disc died. (I planned on swapping the posi unit for my original axle's "open" differential, then snapped the bolt, and couldn't get it out.. dammit.) Then I snapped ANOTHER lock bolt in a junkyard, trying to get 28 spline (90-up) axleshafts out of a v6 f-body.

But like I said, I'm complicating things. Of course, you should change the rear fluid, and check the magnet inside the cover for large chunks of metal. But if all's good, just unbolt your axle and slide the new one under. You could rebuild the drum brakes with new shoes, springs, clips, and wheel cylinders. I recommend you replace the brake hose with a new one- brake hoses deteriorate over time. 'Fact, I hope by now, you've replaced the front brake hoses already! (Don't want them to crack or clog or burst on ya.)

If your drum brakes are in better condition overall than the v6 axle's, you can unbolt the whole drum assembly from both axles, and put your drum brakes onto the v6's axle. But if you rebuild the v6's drum brakes, it should be fine. It's much easier to work on an axle when it's out of the car. Fun tip: When swapping 'em, you can put the tires back on the axle, and wheel the axle around instead of dragging it across the yard. Looks kinda cool, too.

More than you wanted to know, eh? You could do searches on the trans/drivetrain board, too, because like I said, v6 axle = v8 axle in terms of parts & strength & etc.

 

From my reading,
GM offered two posi carriers.
Both kinda weak & "expensive" to rebuild/replace.
Apparently for about $400+ Powertrax is a very wise option.
Sixes & 3:42 & Posi, Also don't believe it existed for our cars.
Never say never, but.....

 

I think te powertrax $400 kit is the superduty one. the reg limited slip diff are around $320 or so.

 

wasnt the iron duke 4 banger that got the 3.42 posi????? in some cases.

 

My car 91 RS with 3.1L came with a posi rear end, sadly I do not know the gear ratio, anyone have any idea on what it might be? I think this was an option included in the O2 package, not sure though.

 

Why not go with a takeout Torsen from SLP? They usually sell them for $99, and sometimes less. The Powertrax, unless they have changed it, is crap. I have driven two cars with Powertrax units in them, and they constantly locked and unlocked, jerking the car, even when going straight. Not to mention the noise...it sounded like they had clydsdales in the trunk!!!

 

I have heard that too & have read different
I only threw out an option or knowledge.
Beyond that, no the solution ain't exactly cheap.
Easy to spend, CORRECTLY about a grand on an axle set up right.

 

The takeout posi needs to be on a 90-up f-body because it uses 28 spline axleshafts. In mid-89, GM went to a 28 spline axleshaft instead of the weaker 26 spline axleshaft. Only way to tell if you have the 28 spline axleshaft on an '89 car is to pop the rear cover off and start counting splines.

Now, an 82-89 car can take the 28-spline axleshafts from a 90-92 car. But, 90-92 cars are rare in the junkyards; and if the pinion lock bolt snaps (like it did on the '90 car I found), and you're lying in the dirt/weeds under the car, you'll never get the snapped lock bolt out. It's tough enough if you've got the axle out of the car!

 

Good point Tom...I got my 28 spline axles from Bruce at Hawk's 3rd Gen.