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The '61-'71 Dodge Sweptline Truck Forum #5

The Official Forum of the DTA. Here's your place to talk about Dodge trucks made from 1961-1971. The Truck of The Week belongs to Mark M.. To view the DTA Photo Albums, click on the "Return to Website" link below. To view Sweptline.Org, click on "DTA HOME"

SWEPTLINE CD's 

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1483 Perkins Lane

Edgewater Park NJ 08010

or Paypal to: jmegee57@hotmail.com

See the CD page at

http://www.olddodges.com/sweptlinecd.htm

61-71 Glove boxes, Core Support/Radiator seals, 69-71 Tool Stowage Decals, 69-71 Firewall Insluation Pads, and A100 glove boxes.
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Subject:   Re: 8.75" Chrysler rear axle, 3rd member - which one is best?
Name:   Jims68
Date Posted:   May 6, 06 - 6:05 AM
Email:   jmegee57@hotmail.com
Dodge-Link   http://www.olddoges.com/sweptlinecd.htm
Message:   Walt, here is some help that I recieved from JEFF C. I hope these notes that I saved are usefull to you. I know they helped me:


BELOW THIS INFO CREDIT GOES TO JEFF C.



There are 3 common center sections or pumpkins for the 8 3/4. The last 3 digits in the pumpkin housing for these are 741, 742, and 489.

Stay away from 741 if you can because it has a small pinion shaft diameter. The 742 is the next improvement. Some say this is the strongest and best because of its large pinion diameter and the fact that pinion depth is adjusted with shims. It also has the best limited slip unit, which uses replaceable clutch discs.

The third series is the 489. This has the largest pinion but it is adjusted with a 'crush sleeve' which is the weak link in the design. It uses the Auburn cone style limited slip which is not rebuildable in the normal sense without some machine work.

You can get a solid spacer instead of the crush sleeve for the 489 which makes for a very strong differential.

All of these center sections will interchange from axle to axle. All of the limited slips are interchangeable, as putting a 742 clutch type limited slip together with a 489 ring and pinion. You must match the ring and pinions themselves by type, and cannot use a ring from one and a pinion from another. You cannot put a 742 ring and pinion in a 489 carrier.

Those axles with nuts are 'tapered axles'. Avoid them if at all possible. That center section will fit in any other 8 3/4 rear end. The other types use a 'flanged axle' which is semi floating and stronger.




Check your case number, if it was a 741
case it was the weakest of the 3 late cases.
Sounds like a busted pinion or stripped ring
pinion, must of had some hard use to do that
to it.
Look for a 742 or 489 case as a replacement
(last 3 numbers cast into case), a S or X is often stamped into the bottem of the case
to indicate that is a suregrip. 489 it the
strongest of the 3 and you will find them
in vans and trucks most often, the 742 is also very strong and was used behind the
hemis in the late 60s.
If you find a Auburn suregrip unit you
will need to upgrade the axle bearings
to the green bearings if there is no
pin to float the axles in the center.
Your axles should be fine, but when there
out have them checked for straitness just to
be sure.




1-3/8" small stem pinion... (aka. '741')...
Carrier casting numbers: 1820657 (1957-1964), 2070741 (1964-1972). This assembly was typically used in low weight/low horsepower applications through low weight/medium horsepower and high weight/low horsepower applications. Pinion depth and bearing preload is set with shims. Differential bearing setting (ie. backlash ) is set with threaded adjusters.


Axle and Housing Notes
Because the 8-3/4" axle was available in most body lines, there are a variety of housings available. The 8-3/4 was also available in the 58-74 D100/W100 trucks (and variants), the 64-70 A-100 trucks and vans, the 67-70 A-108 trucks and vans, the 71-74 B100/B200 vans and non-listed 57-64 full and mid-size car models.
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