742 versus 489?

[MoparLeo]

742 with the better clutch type Sure-Grip as opposed to the cone style Auburn type.

 

[dvw]

The clutch sure grip will fit any carrier. It is the better sure grip. Last used in 741, 742 1968.
Doug

 

[R/T Boy 67]

As Dipstick mentioned, the larger diameter at the pinion head is to prevent pinion deflection and broken teeth, not to increase shear strength.

 

[mike.c]

HI ,i have read this 7everal times and the question i have is can you use a 1 3/4 in pinion in a 741 ,i have a 2070741 with stock factory 1 3/8 pinion and want to up grade to the 1 3/4, whats the difference between the two the 741 and 742 any help would be greatly appreciated thank you.

 

[john-9]

the 742 case uses much larger pinion bearings than the 741 case -- so unless you want to machine your 741 pinion bearing pockets out to 742 bearing sizes ,,, but why bother ,, finding a 742 case is not hard -- although there is nothing wrong with the 741 case
742 case pinion bearings HM803149 / HM803110 --i.d. 1.750" ,,, o.d. 3.500"
HM89443 / HM89410 -- i.d.1.312" ,,, o.d. 3.00"
741 case pinion bearings HM89446 / HM89410 -- i.d. 1.375" ,,, o.d. 3.00"
M88048 / M88010 -- i.d. 1.312" ,,, o.d. 2.687"

 

[5.7 hemi]

You want the ultimate 8 3/4? Use a 489 case, crush sleeve eliminator kit, and your golden. If ya can’t get a 489 case/crush sleeve eliminator, then stick with a 742. Wanna go big? Dana 60.....boom, drop the mic!

 

[mike.c]

the 742 case uses much larger pinion bearings than the 741 case -- so unless you want to machine your 741 pinion bearing pockets out to 742 bearing sizes ,,, but why bother ,, finding a 742 case is not hard -- although there is nothing wrong with the 741 case
742 case pinion bearings HM803149 / HM803110 --i.d. 1.750" ,,, o.d. 3.500"
HM89443 / HM89410 -- i.d.1.312" ,,, o.d. 3.00"
741 case pinion bearings HM89446 / HM89410 -- i.d. 1.375" ,,, o.d. 3.00"
M88048 / M88010 -- i.d. 1.312" ,,, o.d. 2.687"

 

[mike.c]

I get it now, i was confusious, on the bearing diameter,i am on the right path now ,thank you for your help and time,peace.

 

[66-67-Belvedere]

The Mopar factory used a solid sleeve but the aftermarket makes a crush sleeve. If you have the '742 professionally rebuilt, insist on the solid sleeve. I specified the solid sleeve and as I reviewed the build before they shipped it back, I asked which sleeve was used, they said crush so I had them tear down to meet my build requirements. Unfortunately, one cannot inspect the crush shield, so I hope I got what I asked and paid for.

The '742 was the performance differential until the '489 came along, so use it in good health.

For safety, get a US Car Tool driveshaft loop:
http://store.uscartool.com/Bolt-In-Driveshaft-Loop-64-72-Mopar-B-Body-70-74-Mopar-E-Body_p_21.html

 

[hunt2elk]

The Mopar factory used a solid sleeve but the aftermarket makes a crush sleeve. If you have the '742 professionally rebuilt, insist on the solid sleeve. I specified the solid sleeve and as I reviewed the build before they shipped it back, I asked which sleeve was used, they said crush so I had them tear down to meet my build requirements. Unfortunately, one cannot inspect the crush shield, so I hope I got what I asked and paid for.

The '742 was the performance differential until the '489 came along, so use it in good health.

For safety, get a US Car Tool driveshaft loop:
http://store.uscartool.com/Bolt-In-Driveshaft-Loop-64-72-Mopar-B-Body-70-74-Mopar-E-Body_p_21.html

The 742 never used a crush sleeve, that was new in 69 with the 489 case.

 

[5.7 hemi]

The 742 uses shims, Dana 60 also. 489 is crush sleeve and a solid spacer with shims is an aftermarket upgrade the makes the 489 really strong.

 

[451 Big Block]

I ran 630 HP in my 3675 pound Charger thru a 741 case with 3.91 gears going 1.6 sec 60 foot on 10 inch slicks. No trans break. Never had a problem. When a 4.3 gear spool went in, used a 489 case. The 8.75 pumpkin is stout.