[Eddie]

Hey guys, I was pokin underneath the Challenger today and I was thinking,, is this thing gonna hold 600+FT. Lbs. and my manual Keisler RS 5-Speed with 17X8 Drew sized Rubber? Should I sell it to a dude who wants it for his project and invest in a New Strange or Moser Dana 60? If so whats this '489' casting worth? I was thinking a new Randy's Ring&Pinion built center section with a Torsen geared diff and alloy axle shafts in 35 splined size that way if I decide to use a Dana the axles would swap over. Stupid, smart, leave it alone??

[fbernard]

Hey guys, I was pokin underneath the Challenger today and I was thinking,, is this thing gonna hold 600+FT. Lbs. and my manual Keisler RS 5-Speed with 17X8 Drew sized Rubber?

From my experience, the Tremec will fail first.
For details, 26x8 slicks did OK for 3 years, 28x10.5 rubber killed the Tremec instantly.
With street tires, you won't have any trouble.

I am in the process of buying a TF727 with a GV overdrive.

[dave-r]

I am in the process of buying a TF727 with a GV overdrive.

I was years ahead of you there.

Eddie that axle sounds pretty strong to me. My axle survived with some strip action and a lot of street abuse and i was still running the original shafts, suregrip, bearings etc.

[Eddie]

I am in the process of buying a TF727 with a GV overdrive.

I was years ahead of you there.

Eddie that axle sounds pretty strong to me. My axle survived with some strip action and a lot of street abuse and i was still running the original shafts, suregrip, bearings etc.

Cool, I think I'll stick with the 8.75 and build it up. Fabien's experience with the Tremec has me feeling but I think I'll take my chances with it cause I wont be using slicks,,ever! .

[drewcrane]

I didnt see this post, but I have 4 different cases 2 are 489 cases one has 3:91,3:55,,and currently I have 3;23,S ,The clutches are bad so only one wheel spins, but I did replace the stock axles with Strange axles ,(did that 4 years ago)I just didnt trust the stock axles, I have seen them break, but the 8.75 rears stay together ,and with the OD it might take a little stress off the rear

[Eddie]

I didnt see this post, but I have 4 different cases 2 are 489 cases one has 3:91,3:55,,and currently I have 3;23,S ,The clutches are bad so only one wheel spins, but I did replace the stock axles with Strange axles ,(did that 4 years ago)I just didnt trust the stock axles, I have seen them break, but the 8.75 rears stay together ,and with the OD it might take a little stress off the rear

Thanks Bro! Thats what I'll do then! I can get a new Nodular Iron '489' case from Dr. Diff built with a Detroit True-Trac, US Gear 3.55 Ratio, 1350 U-Joint for around 1285.00 plus the stronger axles for another 300.00 bucks. Time to save! Should be a strong butt!

[dave-r]

I can get a new Nodular Iron '489' case from Dr. Diff built with a Detroit True-Trac, US Gear 3.55 Ratio, 1350 U-Joint for around 1285.00 plus the stronger axles for another 300.00 bucks. Time to save! Should be a strong butt!

Those things are rock hard mate. Very strong.

[Adrian Worman]

I didnt see this post, but I have 4 different cases 2 are 489 cases one has 3:91,3:55,,and currently I have 3;23,S ,The clutches are bad so only one wheel spins, but I did replace the stock axles with Strange axles ,(did that 4 years ago)I just didnt trust the stock axles, I have seen them break, but the 8.75 rears stay together ,and with the OD it might take a little stress off the rear

I got me a used SureGrip diff unit that I wanna stick in my 8 3/4 rear, I haven't stripped it yet but when I do how do I tell if its toast? Its a cone type I think, seen an article on how to breathe new life into it, just thought it would save a load of stress if I knew what to look for when I inspect it.

[Eddie]

I didnt see this post, but I have 4 different cases 2 are 489 cases one has 3:91,3:55,,and currently I have 3;23,S ,The clutches are bad so only one wheel spins, but I did replace the stock axles with Strange axles ,(did that 4 years ago)I just didnt trust the stock axles, I have seen them break, but the 8.75 rears stay together ,and with the OD it might take a little stress off the rear

I got me a used SureGrip diff unit that I wanna stick in my 8 3/4 rear, I haven't stripped it yet but when I do how do I tell if its toast? Its a cone type I think, seen an article on how to breathe new life into it, just thought it would save a load of stress if I knew what to look for when I inspect it.

The cone type uses a special machined cone that has a taper to it and grooves to match the case. When it wears, it prevents the cone from contacting the bottom of the case in an even 'pattern' and it sits lower in the case, sure you can machine a shim to raise the cone up but I think it's a crutch. The clutch pack types wear the friction discs like a auto tranny friction, the discs become worn and shiny. Auburn cone type sure-grips have a trade in program where they sell you a new one and credit your core. I dont know of a re-build kit for them. You can take them apart and maybe Auburn will sell you a new cone but if the case grooves are worn..... I thought about building my own, but by the time you piece meal the parts you dont save a damned thing. You could contact Dr. Diff, his name is Cass Eslick 406-883-4772 he'll set you straight Ade his customer is service is excellent and very high quality parts. www.DoctorDiff.com

[Adrian Worman]

Cheers for that Edd, your right, the mod tips for that diff say about machining the cones seat and using shims. In all fairness it does say it will only breathe new life into a worn unit, never claims to ne a miracle cure. I'll check out Dr Diff

[Adrian Worman]

I just finished readin this months Mopar Action on the crapper and they had a really good article on a fabricated case 8 3/4" axle and diff from Moser Engineering. Looks real impressive, I don't know how to get it on here, worth buying tho Eddie

[Eddie]

I saw that same article at Drew's home while on his crapper! They are using it on their 69 RR project I think.

[Adrian Worman]

No, sorry mate, it was Mopar Muscle, and they used it on a mental 650hp A body project car