Can I change the Peg leg to Posi ??

[BandAid]

Can this be doen just by swapping parts in the dif,or do I need a whole new axel assembly,I undestand that the gears need to be set up by an experienced person,just need a direction to go and if you have recommenadtion please share ... :wink:

 

[pacecarta]

can b done with axle in car and you dont need new axles or ring and pinion gear (unless you dont have 3.42s right now)

you need the carrier section that the ring gear bolts onto , eaton is a good choice at about 350 from gearsareus.com, but youll also need the larger bearings install kit

for 3.42 gears you need a 3 series carrier for an 8.5 rear for 28 spline axles
if you go for a 30 spline carrier youll need to get 30 spline axles (moser are good)

if you pull a posi from another 8.5 like a 70-81 TA with 273up gears its a drop in replacement (bolt your ring gear onto it and shim for proper backlash)

 

[Hawaiian Turbo]

You could put in a Lock right. It uses your old carrier and you don't have to reset the gears. Just pull the axles, remove the spider gears in the carrier and replace with the new spiders, install little springs, C clips, and you're done. There are some down sides, it's really loud on turns, and once in a while it'll jolt after a turn when it locks back up.

 

[84gnguy]

I put a Lock Rite into my 3.31 geared open 12 bolt 5 years ago..works mint.
Little noisy from time to time,but nothing worth complaining about

 

[BandAid]

I remember my 1st GN did that chatter ,added the GM rear end fluid and it was cured,,have you guys tried that for the noise....thanks for the info,by looking under the car lastnight the rear seems smaller ,are there different one for a NA car,,,no tags or codes anywhere on this car...
http://www.powertrax.com/buicklr.pdf
Do the 7.5 and 8.5 rears both have 10bolts???

 

[pacecarta]

if its not a turbo car (or a hurst olds 442) its should be a 7.5" , unless someone swapped an 8.5 in there
yes they both have 10 bolts but the 7.5 is bolt pattern is flatter at top and bottom , the 8.5 bolt pattern round

the lockrite or locker type conversion uses plates with large squared notches in them , these plates breaking loose and relocking and are what causes the chatter (more like chunking) when turning or anytime the rear is in diff mode and cant be fixed with diff lube. IMO these are more suited for off road trucks at low speeds than drag cars putting down loads of torque at high wheel speed when fighting for traction ,

posi (or also called limited slip ) is what gm used and what you asked about a posi uses stacked clutch plates that are designed to slip on turns and on those rears the diff lube helps it to slip a little easier

 

[Hawaiian Turbo]

Yep, excatly what pacecar said. The reason I put it in was I didn't need to reset the gears. And it's either locked or it's not, no slipping involved.

 

[NJVetteGuy]

I put a Lock Rite into my 3.31 geared open 12 bolt 5 years ago..works mint.
Little noisy from time to time,but nothing worth complaining about

Those lock-rights and powertrax units may hold up on the street with street tires, but if you race at the track regularly with a drag radial or slick it's not going to last long. You're much better off buying an Eaton for 28 spline axles and just swapping it in. You'll need new carrier bearings, races, and a shim kit. Then use a dial indicator to set backlash as noted above. Since you're not changing gears you don't need to worry about pinion depth, etc. I'd change axle bearings/seals while you have it apart, it's a bit intimidating for someone who hasn't done it before but not all that difficult.

 

[Hawaiian Turbo]

I was going low 11's all day long for 2 years and it's still going in a street car till this day. Raced it at least twice a month. I guess it's just a personal preference.