Q: Torque spec for transfer case drain plugs

NewsSkimmer

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Jun 16, 2008, 10:24:01 PM6/16/08

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I need to change the fluid in my 99 OBS Tahoe's transfer case.

Both the NPT drain plugs and the case are looking mighty soft. Can any of
you techs tell me how tight to tighten the plugs?...maybe a torque spec from
the guides? I'd like to just set the torque wrench and be safe.

I have the New Process two-speed push-button model.

Thanks in advance.

NewsSkimmer

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Jun 19, 2008, 12:58:59 AM6/19/08

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Any help available?

I'm going to change the fluid Thursday or Friday.

Thanks

"NewsSkimmer" <NewsS...@sbcglobal.net> wrote in message
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Repairman

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Jun 19, 2008, 7:11:07 AM6/19/08

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Just snug them up, that's all I did when I serviced my Yukon. The plugs are
harder than the case they go into. A drain plug is a drain plug is
a..............

NewsSkimmer

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Jun 19, 2008, 10:35:12 PM6/19/08

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These NPT drain plugs are as soft as butter....that scares me that the case
is even softer.

NPT plugs like this are a pita.

Thanks for your help....I'd still like a torque value if anybody has it.

skimmer

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klutz

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Jun 21, 2008, 9:11:21 PM6/21/08

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15 foot pounds is probably in the ball park. According to my 2005 Silverado
factory shop manual, transfer case drain/fill plug torque specification is
20Nm or 15 lb. ft. for NVG 149-NP3, NVG 246-NP8, NVG 261-NP2, and NVG
263-NP1. Hope this helps.

Repairman

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Jun 22, 2008, 8:52:45 AM6/22/08

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Okay here ya go per my 1999 GM Yukon factory shop manual.

2 speed auto trac transfer case.
Drain plugs are aluminum and case is magnesium. Only aluminum plugs can be
used due to corrosion issues.
Torque spec is 35 ft. lbs. . Which is snug.........

NewsSkimmer

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Jul 26, 2008, 2:59:45 PM7/26/08

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Thanks everyone. I did this job last week and so far so good. I changed the
fluid out to the new blue stuff. I can post the part number if you need it.

On the torque, I finally found two torques listed in my book. One for the
B-W and one for the New Venture. I'm pretty sure that the two-speed
pushbutton x-fer case is New Venture because the tag said New Process. The
torque also showed 35 for the N-V as reported in the other post by
repairman.

After two drain and re-fills to get all the old stuff out, I torqued the
plugs. I chose my smallest torque wrench and it went only to 250
in-lbs...about 20 ft-lbs. This wrench is about the length of a nice 1/2"
drive ratchet. The plug started to show some resistance and started to run
out of thread before getting to the 20....so I just stopped. I'll watch for
leaks and only tighten it more if I have to. I doubt it will leak or vibrate
out. I hope never to take these plugs out again.

35 ft-lbs just seems too tight for such soft materials. I think the number
should be closer to the number reported by klutz. That's the one bad thing
about old manuals, etc. When GM makes changes, the consumer doesn't get the
update. Same thing happened to me on some Ford spark plugs in an aluminum
head.

Skimmer

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