What did you do to your NNBS GMT900 Tahoe/Yukon Today?
- Thread starter phattyford
- Start date
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it happened to me before I had my 03 flushed at the dealer drove it home and the next day a few miles down the highway I looked in my rear view mirror to see a giant white smoke trail behind me, immedialty pulled off the next exit and into a parking lot as it started to not want to move anymore. a line had come loose on the transmission and blew all the fluid out, dealer towed it and copped to it, refilled it and it was fine afterwards. It cleaned up the undercarriage for sure 
I knew a guy with an impala ss. one of the last years, shop installed a tranny temp gauge. on the way home the line they used burst and sprayed tranny fluid on the exhaust, caught fire and burnt to the ground on front of him on the side of the road.
he had one of those small in car fire extinguishers. said it never had a chance, maybe 10sec of flow and nothing.
he had one of those small in car fire extinguishers. said it never had a chance, maybe 10sec of flow and nothing.
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mikeyss
Full Access Member
It's a 6L80, so I'm not sure. The fluid poured out through the inspection cover area, and even after sitting for half a day, it's still steadily leaking out. I have 180k on the trans and it's original, but with a circle D 2600 stall converter. I didn't think 6L80's puked the front pump seal like the older 4L60's
mikeyss
Full Access Member
Yeah, that's for sure! But even before this happened, I have all of the typical failing 6L80 symptoms. I haven't heard of many pump seals blowing out on these transmissions, I'm anxious to see what happened
iamdub
Full Access Member
I was seeing a steady supply of low-mileage take-offs on ebay. It's an alternator and likely to run for 200K+ miles. 10K-20K on one is just a drop in the bucket. Can't beat an OEM alt for $120.
yeah, I know basically nothing about automatic trannys. lol. just a wild guess at best. they are still kinda magic to me.
I don't even remember what the pricing was on this one, it's been to loog haha and they never billed till it shipped, which it never did. I wasn't in a hurry and it must have been a good enough price to not go ebay.
I did a quick search. few on there for 160$ these days. I guess I'll keep an eye out.. gm parts direct lists one for 166. but tax and shipping it's probably pushing 200$
iamdub
Full Access Member
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.
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swathdiver
Full Access Member
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 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
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
Full Access Member
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
Full Access Member
ThanksSorry bro.
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
Full Access Member
sucks mikeyThanks
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.
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
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.
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
Full Access Member
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.
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.
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 upgrade
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.
be interesting to see some dimensions and if it could be easily used as an upgrade
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.
