What did you do to your NNBS GMT900 Tahoe/Yukon Today?

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89Suburban

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I spent 3 days claying, compounding, and waxing. Also fully detailed the interior....and I didn't get pictures....because......
My transmission finally blew up... And spewed trans fluid ALL OVER the undercarriage and rear hatch. There was fluid POURING out of the bell housing area and just before it all happened, it had a NASTY downshift, then I saw white smoke out of the back, and then lots and lots of slipping. It doesn't move at all now :(

Sorry bro. :(
 

mikeyss

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Sorry to hear that Mike. On the bright side, now you can build it up right and not have to worry about for years and years afterwards!
I'm going to list my plans for the trans on my build page, and ask Nick, as well as you all, for advice on a few of the parts I'd like to toss in there. I figure even if it's just the pump seal that blew out, there is going to be other damage inside since I have lots of miles on it.
 

mikeyss

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Sorry bro. :(
Thanks :)
I knew for the last 1 year or so that the trans was failing. I never thought it would break in this manner though, haha.
My wallet is still recouping from the LS9 cam swap in my G8 I had to do earlier this year, which had an AFM lifter get stuck - with only 44k on it.
 

randeez

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Thanks :)
I knew for the last 1 year or so that the trans was failing. I never thought it would break in this manner though, haha.
My wallet is still recouping from the LS9 cam swap in my G8 I had to do earlier this year, which had an AFM lifter get stuck - with only 44k on it.
sucks mikey
wish you were closer you could grab the core ive got sitting here and rebuild it before having to rip yours out. it, as far as i know, still goes 1-2-3. after that it just free revs, not sure if clutches or drum or what is junk. never thought there was much wrong with it just havent needed to get it fixed
 

j91z28d1

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The price may have gone up due to the ramp up in purchases. I missed a couple cuz they were bought out from under me. Someone's scooping these things up! I was seeing them for $90ish to $110ish, $120-$130 total with shipping. There are a few (three, I think) different part numbers that will work just the same, so you have options. I was kinda wanting one with the clutch but I'm not sore about not getting it. I think I have the part numbers in a post in my thread.


*EDIT* Ugh. Just scanned ebay. They're expensive now. If it were me, I'd probably go with this one.



OK.. you saved me the hassle of searching.. sold.

130$ shipped for a 220amp alt is pretty good. my oem one struggles and can't keep up at idle in this heat with everything on max. it's better with the brushless fan swap, but still falls to battery voltage after a few mins stuck at lights or drive thru.

I like the idea of the clutch, most of the new performance cars use them but back in 08 only the auto cars used them, not the manual. mines the manual plus I have a bunch of different size pulleys laying around to adjust. so normal is good.

now I need a pig tail haha.
 

j91z28d1

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Thanks :)
I knew for the last 1 year or so that the trans was failing. I never thought it would break in this manner though, haha.
My wallet is still recouping from the LS9 cam swap in my G8 I had to do earlier this year, which had an AFM lifter get stuck - with only 44k on it.


ls9? G8?

is it na? how's that go? everything I see says it's a soft. cam in the mid range. but it really like the idea of a oem idle.
 

mikeyss

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ls9? G8?

is it na? how's that go? everything I see says it's a soft. cam in the mid range. but it really like the idea of a oem idle.
It is na, and My other half wanted it to idle as close to OEM as possible. Honestly, I love this cam. I read in the G8 forums that some people feel they lost low end torque, but I have yet to experience that. To me, it feels a little better than the factory cam driving it casually, but when you romp on it, there is definitely much improved top end power.
 

Doubeleive

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OK.. you saved me the hassle of searching.. sold.

130$ shipped for a 220amp alt is pretty good. my oem one struggles and can't keep up at idle in this heat with everything on max. it's better with the brushless fan swap, but still falls to battery voltage after a few mins stuck at lights or drive thru.

I like the idea of the clutch, most of the new performance cars use them but back in 08 only the auto cars used them, not the manual. mines the manual plus I have a bunch of different size pulleys laying around to adjust. so normal is good.

now I need a pig tail haha.
how did you do the brushless fan swap?
 

j91z28d1

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how did you do the brushless fan swap?


different car.. sorry. when Iamdub first did the alt mod I was talking with him about putting one on a c6. and ordered one, but it never showed up. I put a brushless c7 fan on that car, and it helped the stock alt but not enough.

my yukon doesn't have a alternator.

for a brushless on these trucks, you'd probably need the lingenfelter control box. it will tap into the truck and output a pwm signal for fan speed. and then you'd need to find a fan setup. I believe spal makes the best aftermarket fans, they make most of the new gm oem fans, just in a inverted pwm signal. because gm being gm lol. https://www.lingenfelter.com/product/L460320002.html

if you have hp tuners, there might be a drop down box to switch fan output strategy from on off relay to pwm. Lotta of ecm's have this option, it just doesn't always work like you expect and need to. experiment with the settings. sadly it's just not defined on my off all truck at all, or I'd like into it. really helps the ac in these extreme Temps. but theres a trail blazer ss guy that switched his to the new zl1 camaro fan. it's a oem made by spal. some crazy big brushless 900 watt output thing. it will cool a semi lol. but happily slow down to only what you need on cool days. it's all about measuring up your factory shroud size and see what will work, it if you can make up one.

I haven't looked but I'd bet the new tahoes have switched to brushless and might be a good cheap swap when they hit the junk yards.
 

j91z28d1

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oh yeah, quick search a 2021 definitely has a brushless setup.

be interesting to see some dimensions and if it could be easily used as an upgradeImg_2023_07_22_11_06_01.jpeg

if someone here with hptuners could check for the output drop down box. it might be as easy as that.

could even as the black bear guys if the tables are in the ecm already.
 

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