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

[Doubeleive]

You're really working hard to pretend that you don't understand what we're talking about. No one here has said they're worried about rubber scratching the glass. No one. We've repeatedly used the word "grit," which includes stuff like road dust and sand kicked up into the air and onto your vehicle, which can scratch every surface on the vehicle if it's rubbed on, including wipers moving over the glass. There's no way you don't understand that.

if the rear glass is scratched it's from metal on glass contact such as the arm it's self or the rubber part came off and the metal holder has been scratching the glass, not from the rubber wiper. I suggest a closer look

 

[j91z28d1]

Hows the fluid in the TC?

I changed it back when I got it at 135k ish. (170 something now) it was horrible looking like it had never been changed and had metal on the magnetic drain plug. so I ran it for a few 1000 miles and then changed it again. looked pretty good that time. I haven't touched it since. I honestly never drove it is auto to know if it was noisey before or gotten worse. it's very rare that I'd use it.

it's only a few qts. I'll probably do it again just for the heck of it and see if the drain plug as metal this time.

 

[91RS]

That’s a normal amount of metal on the drain plug for a transfer case. Transfer cases and manual transmissions will always have some. Big chunks are what you have to worry about.

 

[Scrappycrow]

if the rear glass is scratched it's from metal on glass contact such as the arm it's self or the rubber part came off and the metal holder has been scratching the glass, not from the rubber wiper. I suggest a closer look

I hadn't mentioned the rear glass in my Tahoe, but it is indeed scratched. Again, no one is claiming the rubber scratches the glass. It's what the rubber is pushing/dragging that's scratching the glass. It's uniformly scratched across the width of blade, which is evident when direct light hits. I suppose I'll have to break out my DSLR and a macro lens if I care to prove that this is a thing for the doubters, but I really shouldn't have to.

The situations of metal-on-glass you mention would result in defined tracks of scratching (as has happened with the windshield of my '57 Bel Air), which is not what we're discussing.

EDIT to add:

What are wiper marks - DetailingWiki, the free wiki for detailers

Wiper marks are surface imperfections in the direction and line that windscreen wipers move. Simply put, these are marks in the glass caused by the movement of the windscreen wipers. They can affect your vision and are difficult te remove.

www.detailingwiki.org

Wiper marks are scratches in the glass caused by the movement of the windscreen wipers. Windscreen wipers are not perfectly clean, nor is the windscreen itself. The water you might want to wipe off can also contain dirt, dust and other contaminants. When you use the windscreen wipers, they move over the glass, dragging all the contaminants it encounters over the glass. Although glass is very hard and tough, over time it will show visible marks in the glass. These marks are therefore almost always bend lines that start almost vertical and end almost horizontal.

Similar marks can also be seen on the glass on the drivers and passengers side. The rubber seal between the door and the glass can contain dirt. Every time you wind down the window, the dirt is dragged over the glass. The marks on the side windows are therefore almost always straight vertical lines.

 

[Charlie207]

I hadn't mentioned the rear glass in my Tahoe, but it is indeed scratched. Again, no one is claiming the rubber scratches the glass. It's what the rubber is pushing/dragging that's scratching the glass. It's uniformly scratched across the width of blade, which is evident when direct light hits. I suppose I'll have to break out my DSLR and a macro lens if I care to prove that this is a thing for the doubters, but I really shouldn't have to.

The situations of metal-on-glass you mention would result in defined tracks of scratching (as has happened with the windshield of my '57 Bel Air), which is not what we're discussing.

EDIT to add:

What are wiper marks - DetailingWiki, the free wiki for detailers

Wiper marks are surface imperfections in the direction and line that windscreen wipers move. Simply put, these are marks in the glass caused by the movement of the windscreen wipers. They can affect your vision and are difficult te remove.

www.detailingwiki.org

It's identical to how the car-wash brushes end up scratching your paint. Some yahoo covered in mud goes through in front of you, and then your paint catches hell.

(If you take your car off the pavement, and recoil at the sight of filth, go through the self-service bay first, and blow all the big chunks off.)

 

[Charlie207]

Technically when you switch to AUTO mode the front diff remains un-actuated, until such time that rear wheel slippage is sensed. Then when the actuator is engaged, there is a slight lag of around 1/2 second or so for the actuator to extend and push the internal fork. OBS actuators were thermal; the later ones are electric. You can feel this delay in engagement. All this time the transfer case has spun up to the speed needed to match the other drivetrain speeds, so that it's all connected when the front diff actuator is engaged.

And in 4HI or 4LO the front diff is always engaged.

I'm not sure that's accurate. The actuator should be locking the splines together in the front-end as soon as you rotate into AUTO, and the transfer case clutch pack fork is is slightly engaged, for immediate action. The low clutch pressure helps prevent binding during tight turns on pavement in AUTO.

The two speed sensors (one for each prop-shaft) monitor if there is any difference in rotation speed to detect F vs. R wheel slip, and then instantly apply more clutch-pack pressure via the TC motor-to-fork action. A 1/2 second delay in TC clutch lockup is waaaaay too slow to help with traction in a moving vehicle.

Before I swapped my front-end (baaad bearings) it was loud as soon as I switched into AUTO (or 4HI) while the vehicle was moving. Leaving the system in AUTO all the time is why the front diff. wears slightly faster than if you leave it in 2HI., and why you lose a tiny bit of fuel economy in AUTO vs. 2High

This post explain the previous-gen NVG transfer case, but the newer MP3024 (RPO code: NQH) functions similarly: https://www.tahoeyukonforum.com/threads/4-wheel-auto-how-it-works.116141/

 

[89Suburban]

So It's been about 4 years since I deleted the rear wiper. I took these pics of the glass this morning.

 

[Charlie207]

Five inch drip?

 

[91RS]

Yes, the front differential is locked in auto 4Wd.

 

[mikez71]

Thanks for the photo! My eyesight has been declining and I'm starting to wonder if I saw what I saw.. (hoping it's just a cataract in one eye..)
That makes me want a new rear glass. I swear it's also more noticeable when raining. It won't wipe cleanly and you get water lines in an arc, even with new blade.

So It's been about 4 years since I deleted the rear wiper. I took these pics of the glass this morning.


View attachment 471314

 

[Charlie207]

Yes, the front differential is locked in auto 4Wd.

The diff is open (no LSD or locker); the shaft from the passenger side flange to the center section of the diff. is locked together when the actuator motor drives the fork to couple the outer and inner splined shafts together with a cup*.

(I know what you meant, but there are some extra steps happening.)


*Watch the video:

 

[LSCALADE]

Did it take a lot of hacking up to make it fit the OEM housing?

I'm curious about buying some of the projectors you linked, and a pair of El Cheapo housings from Ebay (I see some for like $80), and performing some surgery.

How dumb would it be to jam four of those projectors into these housings? (dumb!!)

View attachment 471297

Make it easy, get a shroud for the 3" projector, install one of these in the low/high beam hole with the nut and drop a shroud on it and you are done. On the turn signal spot get some switchback LED bulbs, white when parking lamps or DRL and flashes amber when turn singnal is on. That would be a quick and very OEM like appearance with excellent beam output. If you put 4 of these in there the misalignment and lack of adjustment on the top ones will drive you insane. Too much hacking.

 

[j91z28d1]

That’s a normal amount of metal on the drain plug for a transfer case. Transfer cases and manual transmissions will always have some. Big chunks are what you have to worry about.

I haven't messed with t-case but did a lot of manauls. they definitely all have metal. this just looked a bit off to me. more like long slivers than the tranny stuff I was used to but definitely not taking it apart since I can switch to 2wd. if it was Awd and sounded like that. I'd have to look into rebuild or replace

 

[Charlie207]

I haven't messed with t-case but did a lot of manauls. they definitely all have metal. this just looked a bit off to me. more like long slivers than the tranny stuff I was used to but definitely not taking it apart since I can switch to 2wd. if it was Awd and sounded like that. I'd have to look into rebuild or replace

Yeah, it'll have some metal on the magnetic plug, but it shouldn't be a ton, and the fluid should be sparkle-free.

Other than chunks of metal, the sparkles are the sure sign of bad bearings.

 

[Doubeleive]

I hadn't mentioned the rear glass in my Tahoe, but it is indeed scratched. Again, no one is claiming the rubber scratches the glass. It's what the rubber is pushing/dragging that's scratching the glass. It's uniformly scratched across the width of blade, which is evident when direct light hits. I suppose I'll have to break out my DSLR and a macro lens if I care to prove that this is a thing for the doubters, but I really shouldn't have to.

The situations of metal-on-glass you mention would result in defined tracks of scratching (as has happened with the windshield of my '57 Bel Air), which is not what we're discussing.

EDIT to add:

What are wiper marks - DetailingWiki, the free wiki for detailers

Wiper marks are surface imperfections in the direction and line that windscreen wipers move. Simply put, these are marks in the glass caused by the movement of the windscreen wipers. They can affect your vision and are difficult te remove.

www.detailingwiki.org

in most cases with our vehicles these marks are superficial and can be polished out
I had these on my 00 that I thought were permanent but they polished out, just took some work
I am not completely disagreeing I am sure there are some light permanent marks that will not come out without advanced polishing
at the point of deeper marks it then becomes a matter of cost to repair versus cost or availability of replacement glass

 

[Doubeleive]

So It's been about 4 years since I deleted the rear wiper. I took these pics of the glass this morning.


View attachment 471314View attachment 471315

use some of that bruces GSR those lines will disappear, you will have apply it with pressure I would use a short ladder or step so you can stand higher and lean into it while applying. glass is harder to polish than paint. you can get it on amazon, virtually nobody sells it retail.

 

[j91z28d1]

Yeah, it'll have some metal on the magnetic plug, but it shouldn't be a ton, and the fluid should be sparkle-free.

Other than chunks of metal, the sparkles are the sure sign of bad bearings.

I didn't expect the fluid to be bad, so I was just used my big roll around drain tank at work. so I never got to inspect the fluid, other than to see it was very black, which is never good for atf ha.

it wouldn't surprise me if it's bearing related. I really should look into those these style work. I just expect it to have a clutch like a auto tranny it could apply and release quickly. but I'm probably wrong as I don't even remember where it got that idea.

it's even odd gm put this tcase in a Denali. I get the feeling it was only the hybrid ones and everything else got the awd. which is weird on its own.

 

[j91z28d1]

I'm not sure that's accurate. The actuator should be locking the splines together in the front-end as soon as you rotate into AUTO, and the transfer case clutch pack fork is is slightly engaged, for immediate action. The low clutch pressure helps prevent binding during tight turns on pavement in AUTO.

The two speed sensors (one for each prop-shaft) monitor if there is any difference in rotation speed to detect F vs. R wheel slip, and then instantly apply more clutch-pack pressure via the TC motor-to-fork action. A 1/2 second delay in TC clutch lockup is waaaaay too slow to help with traction in a moving vehicle.

Before I swapped my front-end (baaad bearings) it was loud as soon as I switched into AUTO (or 4HI) while the vehicle was moving. Leaving the system in AUTO all the time is why the front diff. wears slightly faster than if you leave it in 2HI., and why you lose a tiny bit of fuel economy in AUTO vs. 2High

This post explain the previous-gen NVG transfer case, but the newer MP3024 (RPO code: NQH) functions similarly: https://www.tahoeyukonforum.com/threads/4-wheel-auto-how-it-works.116141/

I missed the link at first.. great info.

I just figured it took atf, bow I see this.

The transfer case requires Auto Trac® II Fluid
GM P/N 12378508


ugh, I really gotta research better haha.

 

[Scrappycrow]

in most cases with our vehicles these marks are superficial and can be polished out
I had these on my 00 that I thought were permanent but they polished out, just took some work
I am not completely disagreeing I am sure there are some light permanent marks that will not come out without advanced polishing
at the point of deeper marks it then becomes a matter of cost to repair versus cost or availability of replacement glass

Sure, I've polished similar scratches out of other auto glass (used cerium oxide on a BMW windshield), but it's preferable to take steps to help prevent it from happening in the first place, thus my additional squirter that started this whole discussion about dry glass & grit.

 

[91RS]

I missed the link at first.. great info.

I just figured it took atf, bow I see this.

The transfer case requires Auto Trac® II Fluid
GM P/N 12378508


ugh, I really gotta research better haha.

That’s for the 800 trucks, these take Dex VI.