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I need help with a torque spec.


Stick

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What is the spec. for the pinion nut on a 12 bolt rear end. Anyone?…Anyone?

 

Thanks in advance

Mike

 

 

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The torque spec is not so much fot the nut but for the pinion bearing preload. per my 72 MOTORS manual used bearings 5-10 inch pounds, new bearings 20-25 inch pounds. Meaning you tighten the pinion nut until there is the above specified resistance to spin the pinion gear. Don't take this advise to the bank just yet though, I'll dig deeper for a better answer.

Anyone else?

 

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70 MonteCarlo - 64 Riviera - 44 GPW WWII Jeep - 77 M882 Mil 4x4 pickup

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1999 Woodward Dream Cruise

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Yep you can take that to the bank!

That is for installing without the ring gear in place. If you were just changeing the pinion seal, you should have used a torque wrench to turn the assembly and see how much resistance it took to spin it. Then on reassembly tighten it to achieve the same resistance as before.

Bob

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I’m confused now. The nut I’m talking about is the one that holds the yoke on the end of the pinion gear for the drive shaft u-joint. I did change the pinion seal and I had to use an impact wrench to take the nut off. Using the info above, I’m assuming I use the impact wrench to tighten the nut?

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if you are familair with the way the axle is assembled it uses a crush sleeve to preload the pinion bearings.

 

what they meant about using a torque wrench before disassembly,is to find the resistence to rotation.this takes a DAIL INDICATOR torque wrench . ....you turn the shaft and read the torque value . then when reinstalling you tighten in small increments , all the while checking the resistence till you achieve the same as before you took the yoke off.

 

i have seen folks make a paint mark on the nut and shaft , then count how many turns it takes to remove the nut . reassemble the same number of turns .

 

if you have the axle apart and the pinion removed it should get a new crush sleeve for assembley.

 

mike

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Wow, I torqued mine to 65lbs. I thought that was what the book said. Just for insurance we put a small weld on mine. I would like to know what the "real" spec is for the yolk nut. Monte

 

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70 Monte Carlo. 355, 10.4 to 1, AFR 210's, 1 3/4" super comps, solid roller 585/597 260/266 @.050 on 112LSA, Edelbrock tunnel ram w/2 600 hp's, 4,000 stall, 4.11. 3800 lbs. 4000lbs with me in it, 12.4 @ 111 mph, 2.000 60' time, launching at 1/2 throttle for 60' to keep from spinning the tires. With that mph it should be between 11.8 and 12.2 once I get it to hook up. New Times coming for the new rear end set up and 200 shot of nitrous.

 

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Quote:
<font face="Verdana, Arial" size="2">Originally posted by Monte:
Wow, I torqued mine to 65lbs. I thought that was what the book said. Just for insurance we put a small weld on mine. I would like to know what the "real" spec is for the yolk nut. Monte
</font>


There is no "real" spec for that nut!
The spec is for the bearing preload.
Think of the pinion bearings like front wheel bearings i.e. too tight it don't turn /too loose it rattles. The "yoke nut" (actually the companion flange nut) pinches the pinion bearings between the "yoke" (companion flange) and the shoulder on the pinion gear.
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Quote:
<font face="Verdana, Arial" size="2">Originally posted by Bob Hansen:
The torque spec is not so much fot the nut but for the pinion bearing preload. per my 72 MOTORS manual used bearings 5-10 inch pounds, new bearings 20-25 inch pounds. Meaning you tighten the pinion nut until there is the above specified resistance to spin the pinion gear. Don't take this advise to the bank just yet though, I'll dig deeper for a better answer.
Anyone else?
</font>


I seem to recall that he is using the correct numbers that I used on my F**d 9".
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call randy's ring and pinion i just put a 390 gear in my 12 bolt and the directions said to torque it betweeen 300 to 400 ft lbs

so i got a torque wrench and torqued it to 250 and then put the end of the torque wrench on a floor jack and jacked it up as high as it could go two times that worked out good if not the bolt wont be tight enough and it will make noise the first time i didnt do that and it made noise heres the ph# 1-800-292-1031

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Here is how I did it (changing the yoke and rear pinion seal only):

- Drained rear end fluid

- Bought a small fish scale at Wal-Mart for $5. Attached the scale to the yoke and measured how much it took to turn the yoke.

- Disassembled yoke & Pinion Seal. It took a 6ft long breaker bar to get the nut off!

- Reassembled with new yoke and seal. Use a new pinion nut. Tightened it with the breaker bar until forehead is full of sweat... biggrin.gif

- Checked to 'force' to turn the yoke with the fish scale again, was approx. same.

- Filled rear diff with diff fluid (don't forget posi additive, if needed)

- Test drive (check for noises)

- Check pinion nut after 200 miles

 

No problem since the last 3000 miles... smile.gif

 

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71 Monte 454 HO 5- Speed "FULMNTE"

01 Camaro V6

Andreas' Monte Carlo Site

Member NMCOA, FGMCC (Event Coordinator)

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"It ain't a car if it's not a Monte"

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