Limited slip installation.

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circlepilot

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(I may have the title wrong, sure grip or limited slip) One of the many individual parts that I'm working on with my build, is installing a sure grip (limited slip?) in my 8.75. When I got the rear end it had a Dr. Diff spool in it. The ring and pinion are a 4:10.
Both the ring and pinion have very little visible wear. After installing the sure grip I set the rear end up (completely) I.A.W. the factory service manual. Never having experience with (limited slip) sure grip, (only open and locked rear ends and I have the third member on a stand.) I have some questions...How hard should it be to turn the yoke by hand? (It can be turned by hand, but it does require something more than I expected) There seems to be a "dead spot" while turning the yoke. The applied gear marker shows a correct "foot print." Lash properly set with a dial indicator and a correct pre-load on the pinion.
Norm

sure grip.jpg
 
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Some Mopar Purists will correct you by insisting it's "Sure grip." Limited slip smacks of GM products. If it's all torqued and shimmed correctly, It should be good. It's going to be a bit stiff until it's broken in. Don't hammer it, and check your fluid frequently. Nice job.
 
did you check pinion run out / I have seen the yoke end bent , a sign is a leaking pinion seal . when I ran the sure grip the car would go deeper into the corner but got a little loose coming out with power transferring back between the left/right wheels, tried changing the stagger but no help because the inside track was wet and the outside dry /but if your on asphalt it might not be a problem
 
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What case do you have? New bearings? Did you set the pinion preload? Did you check backlash in 4 different places? Need more info.
 
What case do you have? New bearings? Did you set the pinion preload? Did you check backlash in 4 different places? Need more info.
It's a 489 case, new bearings and yes set the pre-load I.A.W. the service manual. Yes it was measured in four places with the dial indicator.
Rear End case.jpg
 
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Then it will be pretty stiff to turn. Did u use a new crush sleeve or use the eliminator kit? Post better pics of the pattern u got. Did u use a rag or anything to put resistance on the crown gear while turning the pinion to check the pattern? Kim
 
Check the rotating torque. Is it the same as b4? Did u tighten the pinion nut during the assambly? Kim
Didn't really check the rotation, prior to total disassembly. After torqueing the pinion nut, the rotation was checked with a torque wrench as instructed in the service manual. The pre-load rotation fell into the allowable limits for an original bearing..."0-15 inch pounds."
Norm
 
Well than what was the BL set at. Usually there is some ring gear run out so you have to check it in several places and set it at a compromise number.
 
Factory or aftermarket gear? If Richmond BL setting is ecthed on the ring gear (normally .010). Move the BL to .010 and check rotation. If the tight spot goes away and you know for sure the bearings and races are good more than likely the runout of the carrier is out of limits. I always check the runout on unkown carriers. People beat the ring gears off with hammers instead of using heat to get old ring gears off. A good machine shop can cut the carrier to zero runout.
 
Factory or aftermarket gear? If Richmond BL setting is ecthed on the ring gear (normally .010). Move the BL to .010 and check rotation. If the tight spot goes away and you know for sure the bearings and races are good more than likely the runout of the carrier is out of limits. I always check the runout on unkown carriers. People beat the ring gears off with hammers instead of using heat to get old ring gears off. A good machine shop can cut the carrier to zero runout.
Thanks, I'll look at that. With all of the help here and with all of the advice, I've gotten...I'm going to go back and check everything again, one more time, before loaded it into the banjo. Thanks to everyone for their input.
Norm
 
Is the pinion rubbing the limited slip? It looks like something it's rubbing right above where you can see the springs in your picture.
 
If it has any backlash at all, you're probably good. I have an old friend WL Kitchens in Warner Robins, Georgia whose a renowned old drag racer all over the southeast. He used to set them all up at zero backlash and let um "wear it in". I never saw him have a failure. lol Although I'm sure he probably should have. He's deep in his eighties now, but still races on occasion.
 
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Is the pinion rubbing the limited slip? It looks like something it's rubbing right above where you can see the springs in your picture.
You know I never noticed that until you mentioned it. The chunk is down in the shop, but I went back and looked at my picture and blew it up. First thing tomorrow, I'll check it out. It sure does look like pinion gear marks.
Thanks
Norm
 
That is not unusual to see witness marks on a cone style SG. I have seen them much worse than that. Seems to be a more common occurrence in the 489 case that uses a crush sleeve. That happens when the pinion nut comes loose and the pinion gear leaves those marks on the case.
 
Yup, that's a very common issue and it comes from the pinion nut backing off. My guess is, it's not happening now, but it sure is worth checking out.
 
Just now had the chance to get out a reply...Those marks, must of been there when I got the sure-grip. I just never noticed them before. Cleaning it up and oiling the hell out of everything, enhanced the marks. I checked and there is no contact being made between the sure-grip and the pinion, ran it through a full 360 degrees. Thanks to all for the "heads up."
Norm
 
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