What are the pros and cons of using green bearings for the 8 3/4? This is for my daily driver 69 valiant. I only know what I have read and I am a little confused.

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69 valiant

I would use stock-type bearings. They work well and last a long time. Note that Green is a brand of bearing, not a particular design, but "Green bearings" refers to replacing the original tapered-roller style bearings with ball bearings. They work, and IIUC they're necessary if you're running a spool rather than a conventional differential, but they don't offer a real advantage unless you're building a dedicated drag racer, and the tapered-roller original type bearings offer greater side-load capacity than ball bearings (that's important on the street...not so important on the drag strip). If you put in ball bearings, you're likely not going to have any kind of a big, spectacular bearing failure or anything, but you will likely not drive anywhere near as far before the bearings are loose 'n' sloppy and in need of repair.

The stock-type bearings are also adjustable, which the "Green" (ball) bearings are not.

This topic is a little like carb manufacturers or poly vs. rubber bushings. You'll find strongly-held opinions on both sides.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Which ever way you go, save your right side "spanner nut" bearing retainer plate. These are no longer available and are in short supply.

Last time I needed one, I had to carefully remove it from a used axle shaft. (cut-off the bearing, don't press it off, pressing off the bearing distroys the plate and adjuster)
DD

Thanks Dan and Doc. It wil be in a drag car with a spool.

Doc, I read your reply about saving the retainer in other threads, so I will definately do that if I decide to go the 'green' route.

What if anything will I have to change if I go with green bearings?

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69 valiant

FYI, I have used the "Green" several times and have put over 20K + on them on the street with no problem under high HP.
This is not relevant as you are using a spool but is suggested to remove the axle thrust buttons in the early suregrip applications.
In a race application they have been my car for 6 seasons. No problems.
All in all other than price and not having to set end play it is just personal preference.

There are two different "subtypes" of the green bearings for the 8 3/4". The style that had come out by mopar performance, the flange is pressed on the body of the bearing. Then the later type where the flange rides on a clip.

You want the later kind that rides on a clip. The idea is... if your housing isn't 100% dead straight, which most aren't due to factory tolerances, the pressed on flange type bearings will get tweaked in the housing by the axle causing premature wear and failure. This is the one most people have problems with.

The type where the flange rides against a clip instead of being securely pressed onto the bearing - this allows for a little give to accomodate for uneven housings, etc.

Afaik all the mopar performance ones use the securely mounted flange. I think mancini has the newer kind listed for for willwood brake kits. Check with doctordiff on moparts he has cheaper prices.

Romeo was right about the thrust blocks.... I didn't pay attention to the spool part, but I know that if your not removing them from the stock open differential you must use the steel backing plate gasket to get the spacing right.

Many oems used this style bearing. Toyota, certain ford 9". I'll try to find a picture to post of the flange riding on the clip so it makes more sense.

Snap rings, not clips, thats what they were called... I take no credit for this picture, found it on moparts uploaded by "Kamstra Kuda"



Now imagine if the flange was rigidly mounted to the bearing body. That would place the bearing in the housing at the same angle the housing end was welded on. But if this isn't perpendicular to the axle 100%....

When using the stock tapered bearings, the end play adjustment built into the setup would make the same accommodation.

MO-400 / ST-400 is the one you want, RP-400 is the one you don't want.