3rd member and axles change?

[moparmusclecars]

I have a 489 chunk and rear end complete out of a 1970 6 pack Super Bee (v coded car) auto car. I am assuming 323 gears, but i will need to confirm. Car was wrecked with 9k miles on it. Rear axle tube on one side is bent slightly. I also have a rear end in my 69 Super Bee that has a good housing, but is a 741. Can i use the 741 housing and switch all the guts out of the '70 Super Bee rear end? I believe the housings are the same, correct? Is this something i can do myself, or would i need special tools to accomplish this task? Pull the 3rd member, axles, brakes etc and clean up the housing i will use, installing new axle bearings, seals, etc. I noticed the 741 unit did not have the brake drums with fins, so i am assuming it is no the original rear for my 69 Bee. What more is there to doing this. Since the chunk should all be good still, its merely swapping out parts for the most part, correct? TY for any advice.

 

[Demonic]

Yes, nothing special needed, just have to set the end play, I like to use a dial indicator. The FSM is your friend, likely on the web somewhere too. 8 3/4 center sections interchange as an assembly. Ring & pinion are specific to each casting #.

 

[moparmusclecars]

Housing are the same, correct?

 

[Demonic]

There was a very slight width change in 70 or 71, not sure which. But if it's bent bad, no point in saving it, unless it can be fixed or narrowed.

 

[68Moparmaniac]

I have a 489 chunk and rear end complete out of a 1970 6 pack Super Bee (v coded car) auto car. I am assuming 323 gears, but i will need to confirm. Car was wrecked with 9k miles on it. Rear axle tube on one side is bent slightly. I also have a rear end in my 69 Super Bee that has a good housing, but is a 741. Can i use the 741 housing and switch all the guts out of the '70 Super Bee rear end? I believe the housings are the same, correct? Is this something i can do myself, or would i need special tools to accomplish this task? Pull the 3rd member, axles, brakes etc and clean up the housing i will use, installing new axle bearings, seals, etc. I noticed the 741 unit did not have the brake drums with fins, so i am assuming it is no the original rear for my 69 Bee. What more is there to doing this. Since the chunk should all be good still, its merely swapping out parts for the most part, correct? TY for any advice.

Yes the housings are the same, both from similar year B bodies. 741 and 489 housings are pretty stout pieces, the most significant difference between the two is the pinion bearing diameter, one being 1 3/4 verses 1 7/8. The gear ratio should be stamped on the gear set. I'm assuming this is your first rear end job or do you have experience? If not, there are several web sites or manuals that can walk you through the procedures of 3rd member rebuilding, setting backlash, establishing gear pattern, axle end play etc., the rest is pretty basic wrenching. If you don't have access to a hydraulic press you may need to just farm out the work to someone who has experience with rebuilding your 8 3/4. I guess it all boils down to whether you have the funds to have it done by a reputable shop or if you just need suck it up and learn to do it yourself.

 

[moparmusclecars]

yes, would be first rear end job on a mopar. I think i could do it, but ofc i may not have the needed tools to do it all. At that point, it may be better for me to just take both rear ends to someone that does this. Not necessarily a money factor decision, but i prefer to do things myself when i can.

 

[dukeboy_318]

yes, would be first rear end job on a mopar. I think i could do it, but ofc i may not have the needed tools to do it all. At that point, it may be better for me to just take both rear ends to someone that does this. Not necessarily a money factor decision, but i prefer to do things myself when i can.

The center swap and bearing/seal job is easy peasy. I taught myself at 15 in highschool how to do it, by trial and error. That said, the straightening of the bent axle tube, that really needs a jig to do it right and actually get it straight. and the trick is not creasing or crimping the tube. You'd be money and time ahead to just replace the housing. For a B body, the cost of a good used one is not much.

 

[66Satellite47]

The housing is the same on B bodies. However E bodies(70 & newer) had a slightly wider housing. A 741 is the small 1 3/8" straight pinion bearing pumpkin, 489 is the newer 1 7/8" tapered pinion bearing. The 741 was normally used in small block or low perf applications as I recall. The larger 742 case 1 3/4 straight pinion used in Hi perf vehicles. IIRC the finned drums were on the Hi perf vehicles, but maybe not all.

 

[BeepBeepRR]

 

[Jerry Hall]

If you have done rear end work on other brands, I think you will find it easier on a Mopar. I say, you have another housing just do it. Everything in your housing will swap to the other. Just check or have checked the axle on the bent side.

 

[BeepBeepRR]

Also Toyota Tacomas use the same setup.. easy swap there too.

 

[66Satellite47]

To recap, the 489 pumpkin is the stronger unit, the housings are the same, if gears are what you want, do a swap. The job only requires pulling the axles, un-bolt the pumpkin from the housing. NO SPECIAL tools needed for that. Gear lube goes everywhere, mostly on you if the housing is in the car. Swapping housings is also easy, pull the brakes, axles, pumpkin, then remove the U bolts from the leaf springs, slide the housing out one side. No problem.

 

[moparmusclecars]

Thanks everyone. yes, i have torn down rear ends before, just not on a Mopar. I will be using the good housing, instead of messing with the bent one. So nothing needs to be set up with a dial caliper or anything if I'm just putting new bearing in the housing, using the good axles, and pumpkin assembly, correct? i'm not taking the 3rd member apart. Just basically swapping the 3rd member, and axles, along with installing new bearing. Using all the brakes, backing plates, and drums off the original bee Rear End.