741 open to 489 suregrip swap

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megavites

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currently, my 67 satellite has a 2.76 open 741 rear and I just picked up a 3.23 489 case.
I read somewhere that I would need to change the pinion? Any input on what's needed for this swap would be appreciated.
 
Assuming the 489 setup uses the same sized u joint, no need to change pinion yoke. And you can get a combo u joint that will match small to large if needed.

Assuming your existing setup used oe roller axle bearings and 489 came from setup with same it should be a direct swap

If your 741 was setup for green axle bearings, the 489 will need to be setup accordingly
 
If the 489 case is empty, the 741 pinion will not fit it.
 
If you bought the entire 489 "chunk" which is what we call the preassembled unit, it will swap with no problem. You take out the unit with the 276 gears and install the whole unit with the 323s. About the only thing that can be different is the yoke size. As stated already, They make two: a large and a small. You can get a two sided adapter u-joint from a number of locations that is small one side and large on the other.

As noted above a ring and pinion from a 741 case will not fit in a 489 case.
 
gregpurcell said:
If you bought the entire 489 "chunk" which is what we call the preassembled unit, it will swap with no problem. You take out the unit with the 276 gears and install the whole unit with the 323s. About the only thing that can be different is the yoke size. As stated already, They make two: a large and a small. You can get a two sided adapter u-joint from a number of locations that is small one side and large on the other.

As noted above a ring and pinion from a 741 case will not fit in a 489 case.
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Yes, I have the entire 489 center section. So my understanding is that I'll need to check the yoke size on the 489.
Any links to a vendor that sells the two sided adapter?
 
Make sure you have addressed the thrust block depending on which type of axle bearings you have
 
Make sure you have addressed the thrust block depending on which type of axle bearings you have

He did not say if the 323 unit was a sure grip or open unit. The thrust block is only an issue with rear housings that have been converted to green bearings and center sections running the "old style" clutch style sure grip unit. On the old style clutch type sure grips, there is a thrust block to assure that the axle end play adjustment can be achieved. They tend to fall out of the unit when the center section is removed. The block HAS to be there if you are running the stock adjuster and does not have to be there with green bearings. On newer sure grips and open units it does not fall out so the issue is moot.

I very highly doubt that a 67 Satellite with a 741 case 276 open would have been converted to run green bearings so this is probably something that you don't have to worry about.
 
gregpurcell said:
Make sure you have addressed the thrust block depending on which type of axle bearings you have

He did not say if the 323 unit was a sure grip or open unit. The thrust block is only an issue with rear housings that have been converted to green bearings and center sections running the "old style" clutch style sure grip unit. On the old style clutch type sure grips, there is a thrust block to assure that the axle end play adjustment can be achieved. They tend to fall out of the unit when the center section is removed. The block HAS to be there if you are running the stock adjuster and does not have to be there with green bearings. On newer sure grips and open units it does not fall out so the issue is moot.

I very highly doubt that a 67 Satellite with a 741 case 276 open would have been converted to run green bearings so this is probably something that you don't have to worry about.
Click to expand...
The 3.23 is a suregrip. The 741 in the car now I'm sure is original. The 3.23 is one of the units in this pic. I'm picking it up on Turkey day.
rears.jpg
 
IMHO... if you have the option to get a clutch type (top row except for 2nd from left) you would be better off as the clutches can be easily replaced. all the rest are "cone" type and while they can be rebuilt, require machining.

Regardless of the center section my understanding is that the thrust button or lack thereof needs to match the axle bearings being used.

megavites are you planning on changing out the rear axle bearings and to which type OE or Green?


gregpurcell said:
On newer sure grips and open units it does not fall out so the issue is moot.
Click to expand...

My understanding is that the thrust button doesn't allow the axels to seat properly when using green bearings hence the need to remove it when using green bearings. Perhaps I don't understand the issue correctly? (not flaming anyone I just want to be clear on the issue)
 
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Dana67Dart said:
My understanding is that the thrust button doesn't allow the axels to seat properly when using green bearings hence the need to remove it when using green bearings. Perhaps I don't understand the issue correctly? (not flaming anyone I just want to be clear on the issue)
Click to expand...
The problem with that theory would be that the open units and the later cone type rears do not have removable thrust blocks so that IF that were the case, you would not be able to use them with green bearings. I do not think this is the case. The thrust block IS necessary when running stock axles and a clutch style sure grip. The quickest
way to check if the thrust pin is in place is to look into the center section and make certain that you cannot see daylight coming in from the other side.
 
when i installed green bearings in my dart a couple years ago, i was concerned about removing the thrust block. cass told me that the newer greens will work with the thrust button still in. mine's been in there for 2 years now without any problems.
 
so my understanding is if this 489 case has the larger yoke I'll need the conversion joint (7260-7290).
 
You can check the condition of the sure grip before you buy if you have a couple of axles and a friend. With the chunk laying on the ground or floor,Stick one axle in one side and the remaining axle in the other. Have your friend twist his axle one way while you turn yours against it. It should not slip at all. Which ever of you is stronger should be able to flip the other guy. Some units will "click" some will openly slip but when the engine torque is put on the unit, it will be a lot more force than two guys with axles.
 
megavites said:
so my understanding is if this 489 case has the larger yoke I'll need the conversion joint (7260-7290).
Click to expand...
That should be the only variable in the equation. And I second dana67dart's suggestion that if you can get a unit with a clutch type carrier your better off. They are the ones that you cannot see springs inside of and their not only a stronger unit but easily rebuildable. I've seen cone type units (the ones that you can see springs inside of) that were worn so bad they could not be saved
 
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