[96lt4c4]

Well, after all the checking on the posi, I still have a lot of run out on the ring gear. I think I have wore the area that the ring gear presses on to. I can put the ring gear on by hand, its not a press fit anymore. My new posi will be here today, hopefully that will fix it.

[96lt4c4]

Got the posi tonight and was suprised at what I found. The Yukon and Ford Racing are the same posi. If you look on Yukons website the part number is the same as the part number on the Ford Racing posi that I just got from Summit Racing. When comparing the two units something just didnt look right....







The one on the left is the new one. Why in the hell would Quick Performance send my a posi with half of the hat machined off? From what I can tell there should be no clearence issues with the aluminum case. Even if there is I would much rather grind on the case a little then cut half the material off the side of the posi and make it weak. I thought the machine job on the posi looked like crap. I could tell that someone had put it in a lathe and turned it down. Now I can see how much they took off, and its a bunch! I am begening to wonder if the posi was flexing. Crazy.....

[TimoFinn]

Why in the world would they take material off that place,that`s prone to cracking
I ordered my strange rear with the billet half posi for that reason.

[prostreet6t9]

Thats pretty common actually. Sometimes customers are hard to figure out and will gripe if they have to clearance the case if a thick hat is used. Other customers are fine with it. I personally always use the thick and do some grinding if needed.

[96lt4c4]

Originally Posted by prostreet6t9

Thats pretty common actually. Sometimes customers are hard to figure out and will gripe if they have to clearance the case if a thick hat is used. Other customers are fine with it. I personally always use the thick and do some grinding if needed.

I set it up last night and it clears the case but was hitting the billet cap. A flapper wheel on my grinder took care of that, no big deal at all. I didn’t have to remove much material. I would rather have some off the cap than a bunch off the posi. Still getting some run out on the ring gear though. I check both ring gear mating surfaces, spinning the posi and using a dial indicator and it is dead straight. It has to be coming from this ring and pinion. I go from one thing to another. My back lash is varying about .002 around the ring gear. What is acceptable? I know going through this I have had some with no run out. This is a new Motive performance 3.89 gear. I am thinking about sending it back to Summit and trying another one.

[prostreet6t9]

Originally Posted by 96lt4c4

I set it up last night and it clears the case but was hitting the billet cap. A flapper wheel on my grinder took care of that, no big deal at all. I didn’t have to remove much material. I would rather have some off the cap than a bunch off the posi. Still getting some run out on the ring gear though. I check both ring gear mating surfaces, spinning the posi and using a dial indicator and it is dead straight. It has to be coming from this ring and pinion. I go from one thing to another. My back lash is varying about .002 around the ring gear. What is acceptable? I know going through this I have had some with no run out. This is a new Motive performance 3.89 gear. I am thinking about sending it back to Summit and trying another one.

If I was getting a .002 run out I would set the backlash at 8 at the tight spot putting you at 10 on the loose side,and check patterns.

[96lt4c4]

Originally Posted by prostreet6t9

If I was getting a .002 run out I would set the backlash at 8 at the tight spot putting you at 10 on the loose side,and check patterns.

The pattern looked OK I guess, I am sending it back to Summit and getting another RP. Thats one thing I like about buying this stuff from them is they will take it back no questions asked.

[LS1-IROC]

Originally Posted by 96lt4c4

I set it up last night and it clears the case but was hitting the billet cap. A flapper wheel on my grinder took care of that, no big deal at all. I didn’t have to remove much material. I would rather have some off the cap than a bunch off the posi. Still getting some run out on the ring gear though. I check both ring gear mating surfaces, spinning the posi and using a dial indicator and it is dead straight. It has to be coming from this ring and pinion. I go from one thing to another. My back lash is varying about .002 around the ring gear. What is acceptable? I know going through this I have had some with no run out. This is a new Motive performance 3.89 gear. I am thinking about sending it back to Summit and trying another one.

My motive R&P has .003 runout....I'm running it that way currently. I use up the recommended tolerance for backlash with it being like this.