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-   -   8 3/4 rear end. (http://www.moparchat.com/forums/showthread.php?t=57539)

Cody9902 08-20-2002 03:51 PM

8 3/4 rear end.
 
i found a set of 3.92 gears for my 8 3/4 rear end. i have 3.23s in there now, will these fit on the stock carrier? also i heard somthin like 69 and older rear ends are different than the newer ones. or are they all the same? thanks

6 packin 08-20-2002 04:10 PM

Mopar made a few diff cases and the ring and pinons are NOT interchangable!

Last 3 digits of the casting # as follows!

Small stem units up to 1964 was 657 and another small stem unit casting # 751 was used ever since for non HP application!

Small stem was 1 3/8 inch

Large stem 1 3/4 was used up to 1969, casting # 742

Tapered stem 1 7/8 replaced the 742 case and is casting #489
The sure grips a diff too, but I think interchangeable between the cases! Which were:

1962-1969 Dana Power lock
1969-present Borg-Warner Spin Resistant!

gotcha 08-20-2002 06:41 PM

Just a quick note....the small stem carriers have a 741 casting number and not 751 (Probably a typo). The rear gear will be listed as a 3.91 ratio. The ring gear and pinion must match the carrier as listed, but any third member will fit the housing.

ehostler 08-20-2002 08:01 PM

As there were 3 different carriers, you need to determine what size the pinion shaft (of your 3.91 gears) is. Then look at your carrier and find the las 3 digits of the casting number.

1820657 (1957-1964), 2070741 (1964-1972) use the 1 3/8" pinion.

1634985 (1957-1964), 2070742 (~1961-1969) use the 1 3/4" pinion.

2881488, 2881489 (1969-1974) use the 1 7/8" (tapers to 1 3/4") pinion.

There is alot more good information at http://www.autohobbydigest.com/8_75.html

Duffys Ramcharger 08-21-2002 03:57 AM

O.K. boys and girls:D. Here's the scoop on the 8 3/4

http://www.autohobbydigest.com/8_75.html

Hope this answers you questions.

71dart666 08-21-2002 03:35 PM

Im just curious what was the strongest 83/4ths out there? The 489 or the 741 or 742, i get those last two mixed up and i know one is quite a bit stronger then the other.

gotcha 08-21-2002 06:36 PM

The 741 is the weakest, the 742 and 489 are about a toss up in my book. I have used all three in drag racing, oval track, and street use. The 742 is my personal favorite, but others may feel that the tapered stem 489 is the best. You will not have a problem with either 742 or 489 and ring and pinion sets are easier to come by. The only 8 3/4 failures I have encountered are extreme use (transbrake) where the pinion tries to climb the ring gear on launch. Parts are more readily available with the 489 case.

Cody9902 08-22-2002 03:47 AM

thanks for the help. its very confusing holy. i thought it would be easy. ive blown the rear end in my truck twice and it has the 9.25. i found out from like 76 on all dana 44s are the same, so it was easy to find a set of gears. this is pretty confusing but ill figure it out. thanks


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