ivin74
05 NBS Nali
How many miles are on it?
What did you do to your NNBS GMT900 Tahoe/Yukon Today?
- Thread starter phattyford
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Doug118
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220k
My Envoy had the G80, but in an 8" rear, and when I had a similar issue it was replicated from a stop while already being in a small turn. I was on an off ramp, on a hill, turning to the left. Once I started up again, I would get a small "bump" in the rear and it wouldn't do it going straight, only applying a good load from a stop while turning, couldn't figure out what it was.
I ended up with a chipped spider gear and I just swapped the axle for a SS 9.5" as I have the 4:10 anyway.
I'm sure the few rainy exits from a parking lot lighting up a tire then the G80 locking contributed, and this was before I was aware of their delicate nature.
I wonder if it could be a stuck parking brake back there. That could definitely cause some squat on launch.
I suppose anything is possible, but I have a feeling it may just be the rear end.
I remember when I was removing and putting the drive shaft in a couple times with the rear wheels off the ground spinning one wheel would only make the other wheel rotate the opposing direction "sometimes" I tried it couple times but wasn't sure if that was normal or not. still not sure, seemed odd.
Doug118
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$2800 was a little too good to be true. Noticed it had some blowby so I stuck a bore scope down the holes and found a broken piston. Not the end of the world, just annoying to have to fix it. Oh and this thing is FAST compared to my 8000lb suburban lol
Ouch. Looks like some scoring on the cylinder wall too. i’ll bet somebody ran that thing with 87 unleaded in it. Good opportunity to pull that engine, tear it down on the engine stand, and send it out for machining. You could get real serious about power mods for not much money, too.
Doug118
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I’m going to guess it was ran on 87 as well when gas prices were really high. I’m probably going to pull it and throw some stock pistons in it and put it back in. I thought about doing cam and valvesprings but I don’t want to go down a performance rabbit hole. I was fortunate enough for my wife to let me spend $30k on the stereo in the other truck. Don’t want to push my luck with trying to go fast in the “daily”
George B
¯\_(ツ)_/¯
I was thinking something similar. Originally thought something goofy with hill start assist but the tech noted it was hard to turn the wheels on the rack. I didn’t mention it because if that but I thought it.
just got off the phone with them again, there pretty sure it's not the brakes if it was the pads would have been toasted already. they said the backlash is out of spec a bit but no other symptoms. They are going to pow wow on it and unless they come up with something they said just drive it till whatever it is finally breaks lol
otherwise i'm just spending $1500 bucks tightening up the rear and it might not be the cause.
I might just order a tru trac for it and have it on hand, any extra money is going to wife's new-to-her vehicle right now anyway
That sounds normal for an open diff, with the G80.
If you didn't have the G80, and was a limited slip, then both wheels would turn the same direction.
I missed the original post where you are describing your issue in detail, can you tell me what is going on?
Sounds like you have AWD, just curious, are your tires the same size? Meaning same make/model and tread depth?
Maybe also a sticking caliper that slowly releases and doesn't show it's face again making it harder to diagnose, or a collapsed brake hose.
yes all 4 tires are the same and everything is good they have been rotated and re-balanced, just has some slop when taking off and stopping and taking off again, basically anytime you come to a full stop, or go from a full stop or in reverse same thing. no noise, no leaks, both front & rear diff's have about 80-85k on them, transfer case has 162k, motor mounts are both H3 hummer mounts and the motor does not budge, front diff mounts were already replaced a while ago, transfer case/trans mount is good or looks good, drive shaft is new.
previous to the slop issue I had the u-joints replaced and they f-ked that up and it caused really bad vibration for a few miles like 10 miles, had it towed. and then the drive shaft was fixed some and re-balanced and that is when I started feeling the slop and still had vibration. had a new drive shaft made and even with the new drive shaft and it much better but I can still feel a very very light vibration at 80-90mph, it's not bad at all but I do not have to be looking at the speedo and I can tell when i hit 80, with the previous drive shaft the vibration is worse. so I don't know something is wacky. I know the pinion can cause vibration and I have read the transfer case can as well.
when I get a chance I will look at the rear pads I could have put the clips on wrong, I may just throw new pads and clips on it just to see, but the dealer said the brakes are ok
Doug118
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If I wanted to part it out, I’d make that money back on just the trans, t-case, and front diff
honestly the core charge on that 6.2 is probably about what you paid for it haha. definitely throw a piston in it and left it ride.
So all of this started AFTER you had the rear driveshaft serviced?
Using a prybar, make sure the U joint doesn't move, also, does the U joint move somewhat freely? It shouldn't be hard to move when driveshaft is out of vehicle. Not flopping like a wet noodle, but pretty loose, if the U joint is tight, that could be your issue.
Also, the transfer case does not like an unbalanced driveshaft. Be sure to note with the shop that this happened after your drove it.
I'm starting to lean on a binding U joint without seeing it or driving it.
Edit to add: Hopefully the severely unbalanced driveshaft didn't damage the transfer case, which is why you need to contact the shop..in writing might help via email.
it's not the u-joints, the drive shaft and u-joints are all brand new
this all started when I decided that I wanted to change the u-joints on the original drive shaft.
took it to the dealer and the tech some how managed to press one of the u-joints into the ear so hard it cracked the needle bearing holder, they sent it out like that and as soon as I got on the freeway I had some real bad vibration, they were closed already I picked it up at the end of the day, so I limped it home about 10 miles at 55.
had it towed back the next day, they replaced the messed up u-joint and I picked it up, still had vibration but not as bad and I didn't drive it long maybe 20-30 miles didn't notice any slop per sey, so I had that driveshaft re-balanced and that made it much smoother but still had some minor vibration at 80-90 and around 110mph and I noticed the slop now.
so I had a whole brand new drive shaft made, new u-joints and all. still have the slop, vibration at 80-90 is very very slight I don't think it is the driveshaft and the slop wouldn't be either, it's something else
the bad u-joint was at the pinion end when that happened
