Rear unit Questions

[duodec]

"Green" sealed roller axle bearing set $50. The True Trac requires the removal of the end play adjusters, hence the green bearings.

I've always wanted to go with a Torsen style differential since I saw them at SEMA in the 1980s; shortly after that the company that made them got so involved in military contracts that they let the commercial aftermarket slip.  I'd heard rumor that a few 8-3/4" Torsen differentials had been built but never followed up.  Its good to know there's an alternative.

I gather from looking at usenet posts (I've really been out of the Mopar netloop for the last 8 years or so) that the green bearing versus taper bearing question raises near religious fervor, but I'll ask anyway.

Is gaining the capabilities of a Torsen style differential worth giving up the strength and capabilities of tapered bearings at the axle ends?

I've already got a nicely rebuilt 742 with a clutch type sure grip, plus a core open 489 and a NIB Mopar 2881343 cone type sure grip for use in my '71 Challenger (choices, or just can't pass up deals on parts when I see them)... I've always planned on using OE tapered bearings due to long ago conversations about green bearing limitations and a target 'road oriented' rebuild, not a drag car.

Thanks for any info

Rich

[Chryco Psycho]

there must be a way to limit side travel on a tapered roller without a center spacer

[moper]

I have to side with the "tapered bearings" crowd in terms of engineering. But, I've never seen aGreen bearing go bad from use. I've seen them get rusty after 10 yrs of not moving, but conversely, I've personaly had many factory tapered bearings go bad from normal use. I dont replace for the sake of the "better Green design" because I dont hink they are any better in terms of strength. They just get rid of parts you cant buy new anymore (you cant get the endplay adjusters, only the flange and seal for the other side) or when you need to remove the adjustment. Greens are also a little cheaper when you do buy them IIRC. I can get them as low as $45/pr.

[kingtroll]

King, I have a supplier in Montana, so shipping is a little bit..But it breaks down like this: True Trac $550, ring and pinion $185, bearing/install pkg $100, solid spacer to replace crush sleeve $40, Billet Chromoly 7290 Mopar 29spline yoke $161, "Green" sealed roller axle bearing set $50. The True Trac requires the removal of the end play adjusters, hence the green bearings. The car it went into is driven hard, and makes some power, so I replaced the yoke with one that wont ever break. Labor is always between you and your shop or mechanic. Out the door was about $1250. I can gauranty this car will never break it. I've seen local "rebuilt" centersections go for $250 more, with remanned cone types and no new axle bearings. Some guys pay over and over to replace them. The new Aburns are the same type of cone deal. Once they do slip, they will slip worse,and will be dead fairly quick in a hard driven car. Several locals went thru them in 1 summer. I dont really like doing things more than once. If you do it twice, you have spent more than doing it once really well would have cost.
Bullet, That is a factory clutch type. The factory auburn produced cone type was never designed to be rebuilt. They simply wear the housing and the cones, and they are metal on metal from day one. Some guys do rebuild them, and shim the spider gears so they arent dangerous or weaker, but once they sliip once or twice, they wear, and every time the metal in the oil gets in them and slips again, they wear faster. I'd stick a magnet in there if you rebuild one. It may keep it around longer. The trick would be to win this auction, but dont have him ship the case if you dont need it. It's heavy and that Sure Grip will bolt into any 8 3/4 housing. It will need to be rebuilt tho. The frictions, steels, and springs shouldnt cost more than $70 to make it "good as new".

Thanks for the info moper. That's going to be one of the many future projects for me. Ahhhh soooo many projects .

[Chryco Psycho]

the torson style diff has to be the best design I have seen for a diff

[Ornamental]

I'm considering a hot small block with 500++ hp.

Will a 8 3/4 handle this, and what diff should i get for street use?