STICKY FSM (Factory Service Manual) Corrections

AndyG

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My approach to fuel capacity before a trail ride is just like it is before an airplane ride- Fill the blame thing up!!
 

someguysjeep

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Some FSMs list the torque for the Dana 30 and Dana 44 ring gear bolts (most are 3/8-24) as 100 ft/lbs. This is incorrect, any engineering textbook will tell you the correct torque for a grade 8 3/8-24 bolt is around 50 ft/lbs.

https://www.almabolt.com/pages/catalog/bolts/tighteningtorque.htm

this was brought up recently in another post about loose ring gear bolts IIRC.............. scares the crap out of me, the JK Dana 44 axles some of us are using have FSM ring gear torque values stated at 135 ft lbs.
the torque for a 1/2" gr8 bolt is like 80# and your between 9/16 and 5/8 to hit that 135# mark.
are they really stupid enough to keep making the same mistakes over and over in different FSM's? i even called RGA b4 i did this trying to confirm this info......all they said was their stuff could handle it, not whether it was right or wrong.
 
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IOwnCalculus

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this was brought up recently in another post about loose ring gear bolts IIRC.............. scares the crap out of me, the JK Dana 44 axles some of us are using have FSM ring gear torque values stated at 135 ft lbs.
the torque for a 1/2" gr8 bolt is like 80# and your between 9/16 and 5/8 to hit that 135# mark.

Are the ring gear bolts torque-to-yield?
 

someguysjeep

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Are the ring gear bolts torque-to-yield?

IDK honestly, when looked for this spec everything i found said 135#. so that's what i did, even had to make a gizmo to hold the locker so i could get that much force to the bolts.

what scares the crap out of me is i stumbled into another torque list months later that said 135Nm and i'm worried everything i found was bad info copied from 1 bad source to another.
TBH IDK if i ever looked at an official JK FSM, i googled it and read through several JK torque rate lists and they all said the same thing as far as i recall. i didn't feel right about it and made calls to try and figure it out but nobody gave me a straight answer.

either way it's done and i'll have to suffer the mistake if it is. the axle still needs some break in miles and an oil change so i'll definitely inspect them when i get back in there.

here is 1 of the lists i saved because it had multiple axle info on it (from crawlapedia).

gear spec.PNG
 
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whitrzac

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05/06 wiring diagram manual has the #4 clutch bypass fuse as just shorting out the clutch switch. Its tied to the ecu somewhere. The 4wd light comes on, the idle rises a bit, and it eventually resets to not being bypassed anymore.
Cutting/shorting the clutch switch wires at the switch doesn't turn on the 4wd light, or raise the idle and is a permanent bypass.

There were other errors in the wiring section, but I dont remember them off the top of my head
 

Old_Crow

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are they really stupid enough to keep making the same mistakes over and over in different FSM's? i even called RGA b4 i did this trying to confirm this info......all they said was their stuff could handle it, not whether it was right or wrong.

I used to know someone who wrote automotive tech manuals for a living. She was neither an engineer nor much of a mechanic. They're like actors...they work from a script and as long as it's all spelled correctly, that's the end of their proof-reading skills.
 
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hear

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Compared to the 99 XJ FSM, the TJ FSM's are the gold standard. Trying to get Xj Buddy's OBDII reader to connect....there are so many tiny mistakes in the wiring diagrams, extra complicated because there was a diesel version that changes tons of stuff. In particular there are 2 grounds on the data link connector that go to G102, but the grounds diagram only has G102 listed on the diesel version. I may have to find the corresponding circuit on the 99 TJ and pray they ground the same way.

So yeah, let's remind ourselves how lucky we are to not be XJ owners.
 

SSTJ

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I used to know someone who wrote automotive tech manuals for a living. She was neither an engineer nor much of a mechanic. They're like actors...they work from a script and as long as it's all spelled correctly, that's the end of their proof-reading skills.

Like some of the pictures, I gather!

Screen Shot 2023-01-05 at 10.33.45.png
 
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