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9" pinion yoke swap/set-up

tarafied1

tarafied1

Well-Known Member
Just got home from Saudi. Took the car out and it was making horrible noise from the rear axle. I pulled the diff and one of the carrier bearings failed and chewed up things. I swapped out the diff but the yoke was different. I swapped the yoke and just tightened the pinion nut with the impact. The rear whines pretty bad now. I didn't drive it far to hear the noise. I read that I shouldn't have tightened with the impact. Can I fix it now? Do I need a new crush sleeve to re-set pinion pre-load? I don't have an inch "bar" type torque wrench either. I don't have lots of time before Power tour.
 
I've been told once you "crush" it's done. Could be true or not.

I used a torque wrench when I did mine IIRC.
 
Yep, I would say you need to start from scratch.....BUT......once the gear pattern has been worn in, you will most likely never stop the whine because you can never match the original crush.

You would have had to compare the thickness of the yokes and then calculate the distance the yoke was in and then set the new crush to that point and maybe....just maybe you could be lucky. Then again, luck could be on your side and one time, you hit the position just right......

At least that is my thoughts here.
 
Regarding the crush sleave, I don't think that has any bearing on the gear mesh, it's there to simply keep the proper preload on the bearings. I thought with a 9" you set the pinion in the small housing, get the preload set, then adjust the pinion depth via shims placed between the pinion housing and the main chunk. The pinion depth and the side to side adjustment at the diff bearing is what I thought controlled the gear mesh setting and back lash. All of that is verified with the paste brushed on the gears, and a dial indicator to check the backlash.

I do agree you need to start over. Since you are reusing the gears, it probably would have been a good idea to check the pattern before removing the bearing so that when you put it back to gether you could have replicated the pattern as best you could...

Even though I've never done a 9" I'm sure fundamentally the setup procedure is probably similar to an 8.8 and 12 bolt... just different manner of adjusting I would think.

If you don't have a in lb torque wrench then you could theoretically attach a piece of lightweight pipe to the yoke extending it out at least 12". At the twelve inch mark, incrementally add a known amount of weight until the lever starts to turn the yoke. then you can caclulate just how many inch pound of leverage where required to spin the yoke. It's not perfect but I used this method as a secondary check to using an in lb torque wrench, and it proved out fine for me...
 
yes on the new crush sleeve. if removing the yoke, replacing the crush sleeve & retorquing doesn't fix it, i've got a good 3.50 chunk you can borrow if you run out of time. it's got richmond gears, which are a little noisy even when set up properly, but just been completely rebuilt.
 
I just realized your reference to the diff was actually the whole center chunk assembly... when I think "diff" I think of the part that the ring gear and rear bearings attach too... which would require a complete setup. Since you are not repalcing the whole gearset, the in lb torque wrench won't do you any good because that measurement is supposed to be done with only the pinion installed... the diff carrier and gears will add resistance and give you a false reading...
 
Instead of installing a new crush washer, why not put in a solid spacer and shims. that's what my new 9" came with, and when I had to change the yoke, 'cause it came with the wrong one. the shop just removed the old one and installed a new yoke with just an impact wrench without having to deal with a crush washer. I've got almost 6k miles on the pumpkin without any issues.
 
I've heard of those but you see I'm leaving for the Power Tour June 2nd. Next week I will be travelling for work and so I don't have time to order parts and wait, put it together and find something else is wrong.
I pulled it apart today. Took the 5 bolts from the pinion carrier out and pulled just the pinion assembly. I took it to the Ford dealer and we checked the rotational force, it was too loose. We tightened it to spec. ~16 inch pounds on used bearings. I put it back together and drove it. It's better but still noisy.
This is the 3.73:1 center section I got from Rick. If I recall he said it was noisy before so maybe it's normal. Anyway, I'll drive it as much as I can to make sure I trust it.
Thanks for all the help.
Steve,
I may take you up on just hauling that thing in the trunk, just in case...
 
Turn up that there fancy music box you got in that thing and get on down the road.........
 
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