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Z-71 Skidplates - Installation on my 2007 Avalanche LTZ

Hondo

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Dec 17, 2010
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I wanted to have the factory skidplates on my LTZ (I do go off road with the Av) so I ordered the factory skidplates from GM Parts Giant.

http://www.gmpartsgiant.com/

Front Skid plate - 15843753............ $28.73

Xfer Case Skid Plate - 15049809............ $25.56

UPS Ground shipping............... $8.70

Total.................. $62.99

I went to the hardware store and bought 8 each M10 X 1.5 X 25 buttonhead bolts ( I found this info at a GM Truck forum) and fender washers. The GM bolts are $6 each (self tapping) but all of the hardware I bought cost me approx $8 at Ace hardware.

Here are the two skidplates.

The larger plate is the front plate that protects the front differential & engine- it is made of aluminum.

The smaller black plate is made of steel and protects the transfer case-



Here is the M10 X 1.50 tap, a buttonhead bolt and a fender washer-



These are the 4 holes that I tapped for the transfer case plate. I did have to ream the holes out a bit with a 3/8 bit to get the tap started.



And these are the 4 holes that I tapped for the front plate -



A closeup of the transfer case plate -



A rear view of the transfer case plate  (it covers the lower portion of the transfer case completely)



And a view of the front skid plate -



Because of their location I used a good bead of ant-seize compound on the bolts to fend off corrosion.

So for about $71.00 my LTZ has the factory plates installed. The job took about an hour  and was IMO a good investment.



 

nickaz

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Quick question. Are the holes there for the plates or did you have to mark and drill them? Do you have the parts number by chance?
Thanks for the post and pictures.
 

Hondo

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The holes for the skidplates were there, but they were not tapped.

I had to tap them to use the hardware that I wanted (instead of the expensive self tapping GM bolts).
 

JVZL1

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The front skid plate holes on my 03 Z71 are stripped out.  :E: I considered drilling and tapping.
Then decided to use grade 8 bolts with nilock nuts and thread lock.
I also run a steering stabilizer witch utilizes the front hole. Wish I had another arm and hand with double joints.
But relay not that bad.  
JV
 

joeyz34

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Dec 6, 2007
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costa mesa, ca
so my av really doesn't want its transfercase protected apparently... broke one tap off in the frame last weekend, tried to get it out but couldn't without an extractor, so i figured screw it, 3 bolts will do... went and got another tap, and that one broke today  :E:

front plate was super quick to put on  :D
 

ltklein

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Mar 3, 2005
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Hades, Aridzona
Bummer on breaking the taps...getting them out is always a challenge..

If you have access to a wire-feed welder...you can spot weld a smaller bolt to the broken shank and back it out with a wrench.  An extractor will work if there's enough of a stub...but very hard to drill a hardened tap for an internal extractor.

For those in the audience that haven't done a lot of hole tapping...make sure you use a bit of technique.  You need to lube it constantly as you cut threads (I use WD40 cuz it's convenient).  Screw tap in until it seats...turn another 1/8 to 1/4 turn...and then back it up 1/2 turn...

It takes a bit of pressure...but it has to be measured.  The tap won't flex before it snaps.

Spray again and then turn back in...then a bit further..then back it out...

If you're not making progress..use a bit more pressure.  You'll get the feel for it...

Every few turns...back it all the way out to "back cut" the threads as junk shavings can ball up behind the cutter to..

The shavings come out in the grooves on the tap...





 

pacmano

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Apr 15, 2012
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Just did this, easy add on.  Parts are really cheap in ebay, although I went the same route you did.  Thanks for the write up.
 

CoveredAV

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Sep 2, 2006
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What are you guys using for hardware on the front skid plate?

I have the factory front skid plate on my 2500, and they are attached with fairly large elastomeric pucks incorporated into the hardware that bolts them to the crossmember that ya'll are drilling and tapping.  The plate is not hard bolted.  The elastomeric (rubber, but probably the oil and gas resistant kind) pucks are about 3 inches wide, and over 1 inch thick before compressed to torque (I had to remove my skid plate once to install a steering damper).

My concern for you guys is that when you AV is wiggling and jiggling down the road, especially OFF road, there is not enough working ductility in your hard bolted mounting scheme.  This could potentially lead to the tearing out of the holes you've drilled and tapped, because the twisting stress has to be absorbed somewhere, and with a hard washered mount, there is no give like a big rubber puck would provide.   It seems that GM thought of this issue when they engineered the installation of the skid plate.

My model is a 2005 2500, and it looks like you guys are working with newer body style 1500, so there may be some differences, so pictures of mine may not help.   It might be worth going to a dealer lot, and checking out Z71s with the skid plate factory mounted for your year and model, grabbing the VIN, and ordering the factory hardware to complete your installation with all the functional twist ditch benefits that GM contemplated when they engineered it.  I do not know what they used on your truck, but on mine, they used these big rubber donut spacers that are like body mounts.
 

JVZL1

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I do not know of all 1500 my 03 Z71 with stock skid plates the bussing or grommets are Incorporated in the holes on the front plate. Good point for the front plate the way it is mounted. Do not see a need for any on the Transfer case.
 

BADalanche

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Jan 9, 2004
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I went ahead and bought the 8 factory bolts from GMPD - definitely not cheap @ $5 a pop, but they sure were easy. Only took about 10 min to install both plates. 
 

jackalanche

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OK, so I am leaving an 08 Z71 for a '13 LTZ, and I'd like to put some GM skid plates on this rig (I tend to drive over sh!t like logs, stone walls, etc.)

But the skid plate PN#s listed above (nice write up) come back as valid for 07 - 11 models? I am reading this info right, or will these fit my 2013? If not, does anyone have some PN#s for Z71 skid plates that will fit my 2013?

Thanks kindly in advance . . .
 

jackalanche

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okay, so I think I may have the PN#s for the 2012 - 2013 skid plates:

20944322 - This looks to be a front skid plate
20922755 - This looks to be a skid plate for the transfer case, but I can only get confirmation from on-line GM parts vendors of fitment on 2014 Silverados and Sierras, which kind of spooks me out a little.

further investigation is being pursued . . . .
 

TXBlackDiamond

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I found these pics that seem to show the bushings and special bolt sleeves discussed above. Is this what you are talking about? Does anyone have the correct part numbers and amounts for the sleeves and bushings?
 

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LameSuburbanDad

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I found these pics that seem to show the bushings and special bolt sleeves discussed above. Is this what you are talking about? Does anyone have the correct part numbers and amounts for the sleeves and bushings?
Yes I do. Courtesy of my local Chevy dealership.
Please note that I've labeled "SKID" & "SHIELD" each on their respective papers to help avoid confusion on the wording in the quote direct from Chevy parts (the last image)...If someone is only doing one or the other. Hope this helps!
16020136382721977066750852953111.jpg16020137045955078360662381271289.jpg1602013743007848291123262048638.jpg
 
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