8 3/4 rear maint. and durability

[fizz]

So the rear axle in my 70 r/t seemed sound when I drove the car in the shop, now I am building a 550-600 hp 500 inch stroker, most likely will have a 727w/GV overdrive. At the most it will be driven hard a little on radial street tires. Should I spring for a strange s60 or pull the 8 3/4 apart and freshen it up. No drag strip around here and no fast brand x or y cars to take down.

[BlaineKaiser450]

Which case? 489, 741, or 742? I have a 741 (weakest) cased 8 3/4 rear end with a 3.73 Suregrip behind the 440 and 727 combo in my Plymouth, and some pretty solid street tires with no issues at all. I don't plan on taking it to the track really, just like you mentioned, hard driving on the street and it should be fine. I would guess that my 440 has 550 or more horsepower also. Just have it rebuilt with quality parts and you should be fine.

[AKcharger]

83/4 are pretty tough, I've never heard of one "blowing" unless it's had 1000+ HP going to it.  Is the rear end quiet when you're driving? If so and its working OK I'd drive till fail...which will be a LOOOOOOONG time

[fizz]

Only drove it a few miles but didn't appear to have any noise. It is the stock unit out of a 70 r/t, if that helps identify it. Is there a good reason to do anything like replace the axles for stronger ones, etc. Other wise we will just replace bearings and seals and run it

[AKcharger]

Hi Fizz

The only reason I'd tear into it is if the sure grip function isn't working (clutches worn or cones bad) or if it's making noise. To have a shop rebuild the unit you're going to be looking at $750+ and 99% of the time you will not even be able to tell any kind of difference.  My suggestion is check the fluid level and if it's good, drive it. Again unless you're building your car for the strip you'll be fine, Spend you're $$$$ on things that will really make a difference like Heads/carb/cam or killer stereo

As far as swapping the bearings I would not touch the ones on the Carrier...if you do, you risk getting the ring/pinion out of alignment and tearing the whole Carrier apart. The axle bearing can be changed if you really want to but do NOT use the "green bearings"

Oh, FYI I had my 3:91 center rebuild by a VERY good shop here in anchorage, cost $900, installed it and found the clutch pack too tight so had to pull it and return it to the shop...lesson here is just because something is "rebuilt" doesn't mean everything will be fine.

Below is a narrative on pulling the center section if you choose to and info on rearends

http://www.dodgecharger.com/forum/index.php/topic,2077.msg25934.html#msg25934
http://www.moparfins.com/Repairs/8-3-4_Rebuilding/Information_on_Mopar_Rears.htm

[fizz]

Thanks for the advise. It has a leak at the pinion seal so we'll open it up and freshen it, with a gear change as I plan to go for an overdrive trans. We keep a full time mechanic at the shop working on heavy equipment so my costs aren't so bad. It is easy to get into a trap on spending money replacing parts instead of rebulding them.

[Cooter]

As long as you aren't running a 4-speed and Slicks, an 8 3/4 should be fine. I sold an 8 3/4 chunk 4.56 gear to a buddy that didn't tell me he was running a 4-speed. Well, I asked how it was doing and he replied "It's in a bucket"..[Broken]

[AKcharger]

It has a leak at the pinion seal...

Yeah, no way to fix that unless you pull it all apart. If you are planning to do anything I guess now is the time. Good luck!

[stripedelete]

I wasn't going to touch mine for pretty much the same reasons listed above.  But, it stuck out like a sore thumb since it was the only part on the car that had not been refreshed. 

Glad I did:

[Hot_Rodder]

Stripe, that's looks very familiar.... I pulled my center out of my '69 I used to have after rebuilding the trans, same thing, but probably a little worse.... Luckily I came across a local guy who use to have a Mopar (until rust claimed too much of it), he had the exact same center section as I did, picked it up for practically nothing, tossed it in, and took off..

[stripedelete]

Stripe, that's looks very familiar.... I pulled my center out of my '69 I used to have after rebuilding the trans, same thing, but probably a little worse.... Luckily I came across a local guy who use to have a Mopar (until rust claimed too much of it), he had the exact same center section as I did, picked it up for practically nothing, tossed it in, and took off..

It seems the small pin broke allowing the larger one to walk around.  Was that that the case with yours?  Any idea what caused it?

I'm just glad it was found in the shop and not a thousand miles from home.  I'm planning some serious road trips.