Sure Grip 742 or 489 ???

[ykf7b0]

I want to get your thoughts and opinions on which way to go on choosing a sure grip third member. Please chime in with pro's, con's, and recommendations regarding the 742 and 489 carrier units. Thanks!

 

[Cranky]

If the 89 has a solid spacer, I'll take it. Otherwise, 42. Crush sleeves suck....

 

[70bigblockdodge]

I think both are hard to beat low friction, light weight, easy to set up not working in a hole under a car, on bench standing up. Once set up about the same, if the pinion seal starts leaking or you break the yoke the procedure for removing yoke is different and a extra step is required on 489 you need a turning torque before and then tighten nut to return to that number after repair. The 489 has a little more strength splines and thicker pinion dia, if you were to use crush sleeve eliminator the strength is way up there. DR. diff has a good comparison article posted on moparts.com

 

[5.7 hemi]

Yeah, I'm with what has already been said.

 

[ykf7b0]

Are both the 742 and 489 completely rebuildable?

 

[Cranky]

I think both are hard to beat low friction, light weight, easy to set up not working in a hole under a car, on bench standing up. Once set up about the same, if the pinion seal starts leaking or you break the yoke the procedure for removing yoke is different and a extra step is required on 489 you need a turning torque before and then tighten nut to return to that number after repair. The 489 has a little more strength splines and thicker pinion dia, if you were to use crush sleeve eliminator the strength is way up there. DR. diff has a good comparison article posted on moparts.com

Both need a turning torque to build but the strength really doesn't differ much if at all. The thicker pinion diameter of the 89 case is at the back against the gear head and I've never seen one break there of ALL the cases. If a pinion is going to break, it will be at the nut area and even that doesn't happen very often. When gears fail, it's the ring gear getting shaved by the pinion. Broken yokes....yeah, that can happen on any rear....more splines or not...but doesn't happen very often. If this is for a street car, don't worry about what the rags (magazines) say....even the 41 will do well. Matter of fact, I sell all the 89's and 42's and keep the cheap 41's because they work well too.

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Are both the 742 and 489 completely rebuildable?

Sure Grips? If they are not junk, the cone units can be remachined and all Power Locks have kits....

 

[ykf7b0]

Thanks to everyone!!!!