Charlie207
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This video shows how the transfer case electric motor and shift fork provide preload on the clutch pack in AUTO mode.
What did you do to your NNBS GMT900 Tahoe/Yukon Today?
- Thread starter phattyford
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992dr
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It's more than the seal. But may have spoke too soon. I retract that for now
Haha, it's been leaking for about 6 years off and on. Thought I'd wipe that off the list but unfortunately seems to have made it worse.
Haha it's definitely been a very reliable and dependable vehicle with very few issues. Preventative maintenance has kept me ahead of the game that's for sure.
Already did my rear main and oil pan. Have to do my valve covers which is next on the list. Sometimes you get more pissed off than usual haha
I'm going to see how things go over the next few months and maybe make up my mind then. So, I take that back, I won't be selling my Tahoe.
Charlie207
Full Access Member
At least the valve cover gaskets are a fairly basic job; two beers if you're slacking.It's more than the seal. But may have spoke too soon. I retract that for now
Haha, it's been leaking for about 6 years off and on. Thought I'd wipe that off the list but unfortunately seems to have made it worse.
Haha it's definitely been a very reliable and dependable vehicle with very few issues. Preventative maintenance has kept me ahead of the game that's for sure.
Already did my rear main and oil pan. Have to do my valve covers which is next on the list. Sometimes you get more pissed off than usual haha
I'm going to see how things go over the next few months and maybe make up my mind then. So, I take that back, I won't be selling my Tahoe.
992dr
Full Access Member
As odd as it sounds, some things you look forward to others not so much. The valve covers I'm looking forward to haha.
I'll drag it out for the beers sake
Charlie207
Full Access Member
Always a good time to check the intake manifold bolts while you're in that area.As odd as it sounds, some things you look forward to others not so much. The valve covers I'm looking forward to haha.
I'll drag it out for the beers sake
Charlie207
Full Access Member
Oul change, with some Pennzoil Platinum 5W-30 from the auto section of Hone Depot, and an AC Delco PF63 filter from a 6-pack I bought from a Toyota dealership.
I thought about switching to 0W-30 for the winter, and might do that next time.... I know the debate has been raging for 30 years, but it'll be fine, right?
I thought about switching to 0W-30 for the winter, and might do that next time.... I know the debate has been raging for 30 years, but it'll be fine, right?
Sir_Hiro
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Thats thin..I run Valvoline 10w-30 all year round on my Yukon. I'm in Michigan.
Charlie207
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My main & con-rod bearings were in great shape, and there were new cam bearings Melling oil pump installed last summer, so I'm not worried about pressure or clearances.
The manual calls for 5W-30, and 0W is still 30 weight at operating temps. That's all I know. Someone with a professor hat will hopefully chime in.
Sir_Hiro
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Bobistheoilguy.com is the best place for oil related information. And correction I run 10/40 in the yukon. Got the C10 and Yukon Mixed up. I did the 10/40 since the Oil Pump o-ring is failing and pressures were low IMO
Charlie207
Full Access Member
Wouldn't thicker oil be more difficult for a pump to suck in, with the leaking o-ring?
Sir_Hiro
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I went from 20PSI at idle to 40PSI and it'll stay at 40 now at cruising.
Charlie207
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Sir_Hiro
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My Theory is that it leaks slower past the oring due to the thickness. But I'm not an oil professor lol. I just know oil in engine is good..oil out of engine is bad.
Charlie207
Full Access Member
Diesel bros in shambles.
Scrappycrow
Full Access Member
Here's an excellent video on this: Do Thin Oils Destroy Engines? Lessons From GM’s Massive Recall
A screenshot from the video, with annotations by me:
an oil rating is a range. you can have 2 different viscosity fall within the same range and be called 5w. also they measure viscosity differently at 0c than at 100c. to different tests run different ways. so even that's not apples to apples. like I used to think it was.
figuring out an oil to run sucks. I hate it. the more you learn the more you don't know what to use.
current opinion, if your starter doesn't have a hard time turning the engine over on the coolest day in your area you don't need thinner winter rating. the history of the tests I read was back in the old days the starter literally struggled to turn the engine over on cold days. so they needed thinner cold oil that wasn't to thin and damage the engine once warmed up. these days my starter can probably spin 50w oil at 0c without noticing anything. so eh..
so I don't know man, keep oil in and it let it ride? haha.
I also read the wild swings like 0w50 have so much additive in them to reach that, there's not as much base oil. and the base oil has to be the low number, cause you can only thicken it, not thin it. and then you can lose viscosity to sheer, which our gear oil pumps do. starting at 5 it can be 0 by the end of 5k miles, so starting at 0. I have no clue what it becomes. and then I am still unclear if the amount of additives has a effect of sheer break down. like more sheers faster than base oil breaking down the whole batch. my brain says you can't do one thing postive without the trade off. and I'm still not 100 sure what trade off is.
I have a headache.
I have also read that running thick oil can increase oil Temps, because of being harder to pump and bypassing more volume for the same psi. but also at high Temps the oil thins out a lot and you need thicker oil, like say towing or racing where oil can see and handle 300deg.
and then there's bearings, as long as the oil pressure can keep the crank and rods riding on the oil, the weight doesn't matter. but then there's all the rest of the metal sliding on metal, like lifters and piston skirts. they probably like a little more viscosity, but at the cost of hp and weight from it being thrown around.
I give up. an ls hardly ever has crank or rod bearing issues. but always has cam and lifter damage. afm or non afm.
figuring out an oil to run sucks. I hate it. the more you learn the more you don't know what to use.
current opinion, if your starter doesn't have a hard time turning the engine over on the coolest day in your area you don't need thinner winter rating. the history of the tests I read was back in the old days the starter literally struggled to turn the engine over on cold days. so they needed thinner cold oil that wasn't to thin and damage the engine once warmed up. these days my starter can probably spin 50w oil at 0c without noticing anything. so eh..
so I don't know man, keep oil in and it let it ride? haha.
I also read the wild swings like 0w50 have so much additive in them to reach that, there's not as much base oil. and the base oil has to be the low number, cause you can only thicken it, not thin it. and then you can lose viscosity to sheer, which our gear oil pumps do. starting at 5 it can be 0 by the end of 5k miles, so starting at 0. I have no clue what it becomes. and then I am still unclear if the amount of additives has a effect of sheer break down. like more sheers faster than base oil breaking down the whole batch. my brain says you can't do one thing postive without the trade off. and I'm still not 100 sure what trade off is.
I have a headache.
I have also read that running thick oil can increase oil Temps, because of being harder to pump and bypassing more volume for the same psi. but also at high Temps the oil thins out a lot and you need thicker oil, like say towing or racing where oil can see and handle 300deg.
and then there's bearings, as long as the oil pressure can keep the crank and rods riding on the oil, the weight doesn't matter. but then there's all the rest of the metal sliding on metal, like lifters and piston skirts. they probably like a little more viscosity, but at the cost of hp and weight from it being thrown around.
I give up. an ls hardly ever has crank or rod bearing issues. but always has cam and lifter damage. afm or non afm.
huh. wonder what changed.
yeah, my owners manaul doesn't even list the fluid for this tranny. these hybrid didn't get a stand alone manaul, only a regular denali and then a extra small sub manaul to explain some of the differences.
Googling the rpo code is nightmare with this new ai shit. so that's useless. was it just like a base 5.3 tahoe that got this t case in the gmt900?
Charlie207
Full Access Member
Yeah, I hear you. I have to make so many grown up decisions at work, sometimes I just want someone to point at the thing I'm curious about, and say, "just do it, it's fine".
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I didn’t know yours was a hybrid. What year is it? The 2 mode transmission does still take Dex VI but I can double check the transfer case. All three transfer case options it showed for a 2010 Tahoe all took Dex VI.
it's a 2011 yukon denali hybrid with a NQH rpo code which I believe is the t case.
yeah, I used amsoil version of dex 6 for the tranny. after a 10k mile flush with normal gm branded atf.
