New Rear diff cover and fluid change

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Raptorlander

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26 ft lbs is not really high fyi. Especially for a steel bolt 5/16" in diameter. Frankly it's pathetic for a bolt that size to start stripping at the that torque.

I torqued my rear diff down to 30ft lbs once I got grade 8 bolts. I think Ford torque spec is 33 ft lbs. Either way its not a high torque. Thanks for your comments.
Question, since I sheared the OEM off of my Spicer cover... those grade 8 bolts, did you get the same length as the OEM ones or the Spicer ones. Spicer ones are longer to compensate for the thickness I think.
 

jm77

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Raptorlander

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I used these. Look great and stainless so they won’t rust. Just need a 12 point 10mm socket if you don’t have one. Same length as the bolts included with the cover.

Got yah, I actually ordered these from Summit. It looks like one of my thread holes on the diff was striped partially at the beginning perhaps when trying the shorter oem bolt so was considering a tad bit longer than the spicer so it has more threads to grab on. Thanks for the link, might just stick with these (ARPs) since I have them on hand.
 

Raptorlander

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For those it may help, went to ace and got these grade 8 bolts. Pics attached. Probably could have used a thread chaser but it worked fine. 5/16 X 1
 

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EricM

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You need to torque those grade 8 bolts to a higher spec than the stockers or they will come loose.

Non-graded 5/16 bolt takes approx 5 ft-lbs to properly stretch. Grade 5 5/16 bolt takes approx 10 ft-lbs. Grade 8 5/16 bolt takes about 20 ft lbs to properly stretch the bolt and achieve a clamp load.

You also need to make sure the material the bolt is threaded into can take the higher torque rating when you start making changes. Probably not an issue here given the cast iron diff and realtively small change in torques- but it can be a major problem in engine blocks. You can't swap from stock head bolts to ARP 2000 bolts that take another 75 ft-lbs to achieve a clamp load in every engine block, as it can deform the block or rip the threads out entirely, depending on the engine.
 

thatJeepguy

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In my recent run of maintenance, my next project will be changing out my rear diff fluid

Since I like to do upgrades while doing maintenance, I figured I would put a new rear diff cover on.

this one from Ruff Stuff looks pretty good.

https://www.ruffstuffspecialties.com/catalog/R2486-A.html
No drain plug is a no go for me. In my earlier more inexperienced days ive damaged a drain plug but now to me i feel with a raptor i will never be rock crawling and so to me its more valuable to tot have to disturb the gasket every 50k for a diff fluid change which if you do water crossings or see any water up to the diffs you should consider quite often as its cheap insurance. Ive seen diffs with hella water inside them.
 
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