What did you do to your NBS GMT800 Tahoe/Yukon Today?

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01ssreda4

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So I decided I wanted a little more performance, and towing prowess. I ordered some blue box Motive 4.30 gears, part number GM10-430 and a Ratech rebuild kit. I also ordered a Ratech solid pinion spacer. I decided a new cover would be nice also.

20170217_193628_zps8ktpndap.jpg


Motive gears and cover.

20170222_184610_zpsbfxkhfug.jpg


Opened it up and found an open differential. I wasn't too thrilled about this, I figured it had the g80 locking diff. Only thing I can figure is because it was full time awd they skipped the locking diff.

20170222_184415_zps1ndyttqb.jpg


Found a buddy who had a g80 sitting in his garage across town. So I drove over and got it. Here I was passing The Strand Theatre, it is an old and decorative building. Apparently I was missing the concert.

20170225_191744_zpsdkwhvyhm.jpg


Here's the g80 and the stock diff:

20170227_135423_zpslig1v4j9.jpg


Basically there are two bearing sizes for these diffs. The problem is its not just the diffs that are different its the actual housing that's machined bigger. So the deal is you have a small bearing that mates with some diffs and housings, and a larger bearing that mates with other diffs and housings. You dont know what you have until you measure it. The s10 the g80 came out of has the small bearing, and my housing is machined for the larger bearing, and they dont make a bearing that will make it work. So, back to open diff I go. I set the gears up for those interested at 10 pinion preload with no seal, 20 with seal, and 30 with carrier and backlash was about 5/6. I used a 40 shim under the pinion bearing and the pattern was perfectly centered and egg shaped, no hard lines. I was very happy with how these gears went together. I did have to bend the stock panhard rod slightly to clear the cover since its larger then stock.

20170228_174119_zps7gyiugvz.jpg


Driving impressions: light throttle acceleration is very easy, motor never works hard, the converter tightened up its manners and feels really close to stock at light throttle. Hwy cruise it accelerates easily without unlocking the converter. And the little bit Ive rolled into the throttle the rpms climb really quick. Cruise rpm is about 2500 @ 80, and climbs up pretty quick from there if you increase speed. The truck is on 31 inch tires.
 

TheAutumnWind

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this

So I decided I wanted a little more performance, and towing prowess. I ordered some blue box Motive 4.30 gears, part number GM10-430 and a Ratech rebuild kit. I also ordered a Ratech solid pinion spacer. I decided a new cover would be nice also.

20170217_193628_zps8ktpndap.jpg


Motive gears and cover.

20170222_184610_zpsbfxkhfug.jpg


Opened it up and found an open differential. I wasn't too thrilled about this, I figured it had the g80 locking diff. Only thing I can figure is because it was full time awd they skipped the locking diff.

20170222_184415_zps1ndyttqb.jpg


Found a buddy who had a g80 sitting in his garage across town. So I drove over and got it. Here I was passing The Strand Theatre, it is an old and decorative building. Apparently I was missing the concert.

20170225_191744_zpsdkwhvyhm.jpg


Here's the g80 and the stock diff:

20170227_135423_zpslig1v4j9.jpg


Basically there are two bearing sizes for these diffs. The problem is its not just the diffs that are different its the actual housing that's machined bigger. So the deal is you have a small bearing that mates with some diffs and housings, and a larger bearing that mates with other diffs and housings. You dont know what you have until you measure it. The s10 the g80 came out of has the small bearing, and my housing is machined for the larger bearing, and they dont make a bearing that will make it work. So, back to open diff I go. I set the gears up for those interested at 10 pinion preload with no seal, 20 with seal, and 30 with carrier and backlash was about 5/6. I used a 40 shim under the pinion bearing and the pattern was perfectly centered and egg shaped, no hard lines. I was very happy with how these gears went together. I did have to bend the stock panhard rod slightly to clear the cover since its larger then stock.

20170228_174119_zps7gyiugvz.jpg


Driving impressions: light throttle acceleration is very easy, motor never works hard, the converter tightened up its manners and feels really close to stock at light throttle. Hwy cruise it accelerates easily without unlocking the converter. And the little bit Ive rolled into the throttle the rpms climb really quick. Cruise rpm is about 2500 @ 80, and climbs up pretty quick from there if you increase speed. The truck is on 31 inch tires.

Yeah I don't think very many AWD trucks if any got the g80.
 

TheAutumnWind

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Well since he already had one set up the way I wanted, it's done. Quick drop n swap. Going to pick her up in a few hours. Details to come......


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Looking forward to details. Did you get a new torque convertor? The v6 convertor in the trailblazer give you a nice little bump in stall for minimal $...

edit:
which of course its too late to change... reading comprehension fail. I see now it has been completed already.
 
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ATIII

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Well since he already had one set up the way I wanted, it's done. Quick drop n swap. Going to pick her up in a few hours. Details to come......


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Well here goes first impressions are that it's different. Seems to jump forward a little when shifting at WOT. NOT NEARLY like a hard launch forward upshift like I had on my 2wd-2dr Hemi Ram when I pulled the torque management wire, but it doesn't fall into the next gear anymore if that makes sense. Off the line it seems to have a bit more torque, and it doesn't hesitate anymore deciding which gear to go into to pass. Only have about 30 miles on it so far. Driving it more will tell. I do love that it smells like gear oil inside, the smell doesn't bother me like it does some. And no I didn't get any stains, I checked. He had the paper mat in it too. Gonna park it on the concrete driveway tonight to make sure it doesn't leak.


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Cattivo

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01ssreda4

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Man with 4.30's and 31" tires its buh bye hwy MPG huh? What is your primary use for that rig? Tow pig?

I used to use it as a daily, but not anymore. I use it to pleasure drive on my days off or pull my atvs or Camaro or haul the family when needed. No clue what mpg was before, dont know what it is now. According to the computer it was 13ish. Cruising this morning it was 2500 @ 80mph and 3k @ 90mph.
 

ATIII

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I threw my covers in the bushes:chewie:
Yea I'll admit that I can't stand engine covers either, but the 5.3 is so ******* ugly with the coil packs all over the valve covers and all. So I figured these are the cheapest, best way to dress it up a bit. Prolly gonna get them painted blue to match the paint.

I think I'm gonna "header wrap" my intake, and get some purdy colored sparky wires. I've done absolutely nothing under the hood of this truck until I put the CAI on a couple weeks ago. Everything has been exterior, interior and suspension. But I'm sure the wife will be thrilled I've finally started on it now. $$$$$$$


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