8 3/4 third member q's...

[hot440roddin]

Since I will be having to do a little bit of a rebuild on my 727 TF to go along with the fresh 440 that will be coming along soon, I'd figure I'd ask this question.... I'm my 489 case 8 3/4 rear axle, it has the factory 3.23 open setup. I'd like to go with some kind of a locking differential, but not sure which would be fine for my app. I thought about trying to find a factory setup, but not sure, but to me it would seem that this might be the lowest price way to go..... Otherwise I will have to hunt up a new one, and after some of the prices I've seen, ouch. I've been told that Detroit Locker is the way to go in this case, but what else is there that I should look into? As for the ring and pinion, since I'm wanting to go to a 3.55 ratio, I'm sure that will help on the performance side of things, any set in particular that I should look into, or will pretty much any brand do fine? I do plan on rebuilding the whole rear axle, and perhaps going with those green bearings, but have not made up my mind.... Anyway, look forward to your replies and possible questions. Thanks in advance.

[moper]

I dont use the Auburn type grips anymore. Even the new ones are designed to fail quickly. I'm not a fan of lockers unless it's a drag car that sometimes goes on the street. They are clunky and harsh in most cases, even with the lighter springs. It's more procey, but the one I love for a street car is the Detroit Tru Trac. It's a mechanical limited slip. It never wears out, and never breaks, and slips silently like a stocker around corners. It does have a "hit" to it when you power out of a corner but it's not like a locker... just an odd feeling in your behind when it locks. That's what I'd run.

[hot440roddin]

http://www.summitracing.com/parts/DTL-913A572/
Assuming that you mean this one?

[ShelbyDogg]

That's the one.  I play with it everytime I see their display on the Power Tour. No ratcheting action.

Still might be cheaper to add a clutch style sure grip to your current set of gears. I always see complete clutch centers at mopar swap meets for less than $300.   You might try a want ad on Craigslist.

[hot440roddin]

That's the one.  I play with it everytime I see their display on the Power Tour. No ratcheting action.

Still might be cheaper to add a clutch style sure grip to your current set of gears. I always see complete clutch centers at mopar swap meets for less than $300.   You might try a want ad on Craigslist.

Be nice to be able to find a setup with 3.55's.... I have came across some in the past with 3.91's on it that were used, and at a local car show, I had found a rebuilt setup with 3.91's (but he wanted like a grand for that so....)....

[ShelbyDogg]

If you just find the sure grip and add it to you 3:23 pumpkin, I think you'll be happy with the performance and gas mileage behind a built 440. You'll be able to turn those tires over easily anyway.

[hot440roddin]

Hmmmm, I know with my old 69 Charger R/T with 440 and 727 it was a little fun, but couldn't get the tires to easily spin on the road from any speed (even dead stop)... But it would launch hard... If the tires will fry (on my command) with the 3.23's, then perhaps I'll hold off on the 3.55's, esp if it will still take on a buddy of mine in an '8? Firebird that he replaced his worn out V-6 with a 305.... I'm sure it will anyway, but the more the marrier, lol. On that note, I'm not looking to race the car, but it would be nice if it would live up to it's muscle car heritage, and fry the tires when I want it to.... I did contact Doctor Diff as mentioned by JS29N0B, they made mention of the green bearings though, here's what they said about them:

You won't have problems with the snap ring style green bearings.  The problematic parts are the first generation green bearings sold by Mopar Performance.

So I would think about running them if I want have any problems out of these, I'd like to get away from having to mess with a preload adjustment, and would like to replace the outer and inner seals while I have it apart rather than getting down the road a few miles and it start leaking... Which brings up another question, assuming that my current bearings are good (and I'm thinking they are since there was no roaring sound coming from the back end when I pulled the car home (about one mile, glad to have found something so close to me that I managed to get).... If and when I pull these bearings off, what are the chances of them getting damaged at all when pulling them off to replace the seals?

[ShelbyDogg]

Are they leaking now?

The collar, I guess can be prssed off and reused if you really want to try it.  They go on easily enough. I have never tried getting those off without just cutting off the collar. When you buy a new bearing, you get a new collar, so Why not change out the 40 year old bearings. You won't have to change them again for another 40 years.

For now, if they don't leak, they'll be okay if you just pull out the axles to R&R the gears. I do it all the time.  The end play adjustment is a one-time thing like your front wheel bearings. How often do you adjust those? 

 I'll never trust those ball bearings for side loads. look at the small contact area of the balls compared to the large roller bearings in the stock ones.  How many people do you know that have had to change wheel bearings on their front wheel drive cars when they start howling? All ball bearing type bearings.

[hot440roddin]

I guess this is all something to continue to think about.... The tires that I'll have on the car will be a 28" tall tire, and roughly 12" wide... At least the tread will be 12" wide, I've already got a leaf spring relocation kit, rear leaf spring slider mounts, and am planning on going with something that will help traction out... Which would make it just that more interesting I guess to get the tires to spin, lol.

As for the current setup, I do not think that they are leaking right now, but since the car had been sitting up for some amount of years, and I've had it for a little while now and it's been sitting up, I'd imagine that there are seals that are probably dry rotted by now, and might need to be replaced, otherwise I could just easily see a leak not to far down the road.... Almost like my International pick up that's been sitting.... Went to drive it in the yard, found that the front brakes were gone, but the rears worked.... The seals on the brake wheel cylinders were gone.... Glad I stayed in the yard, and didn't go on the road, bad thing is, there was fluid in the master cylinder, I guess the booster pushed it out...