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

Charlie207 · Mar 26, 2026

Cleaned the contacts inside the accelerator pedal assembly, and there was just a tiny bit of gunk (oxidation?) on the contacts.

Remove connector from assembly.
Remove two T30 mounting screws. (assembly is now detached from vehicle)

To clean:
Remove four Phillips screws on cover (leave the two T30 screws that are also present on pedal assembly).
Remove cover, and remove small board (it's not retained by anything other than the small spring contacts).
Spray contact cleaner on everything and clean with Q-tips (I used DeOxit, but I'm sure MAF, electronics cleaner, iso-alcohol,etc. works fine)
Let dry and reassemble.

No pics... the dog was playing Tetris on my phone.

mikez71 · Mar 26, 2026

Saw this ad on btdieselworks.com

Usually the autosync with tuning package is $400, now it looks like the Autosync by itself is $300, save $100 I guess.

Sir_Hiro · Mar 26, 2026

Replaced both rear calipers and let them gravity bleed for about 2 hours and all rotor temps after city driving are all hovering around 120. So happy with that.
The fluid was black coming out so I will need to flush it soon and I do need to get a proper bleed done. The pedal has always been a bit soft since I bought the truck.

lowh07 · Mar 26, 2026

Got the 6.0 torn down and I’ll get it to the machine shop soon. I decided a forged crank would be good insurance… and since I was already doing forged rods/pistons, it made sense (in my mind) to go ahead and do a 408. So the rotating assembly is on back order… And since I’m doing a 408, I decided it would be best to go with 823 heads instead of the 317s. Found some on marketplace that I hope to have soon.

I’m not sure I’ve been more excited for anything in my life. Possibly equally, but not more.

SpareParts · Mar 26, 2026

@lowh07 @Tonyv__
Maybe Tonyv could use the rods if you're going to toss them.

lowh07 · Mar 26, 2026

SpareParts said:
@lowh07 @Tonyv__
Maybe Tonyv could use the rods if you're going to toss them.

They’re gen III rods but yeah I’m not using them

Charlie207 · Mar 27, 2026

lowh07 said:
Got the 6.0 torn down and I’ll get it to the machine shop soon. I decided a forged crank would be good insurance… and since I was already doing forged rods/pistons, it made sense (in my mind) to go ahead and do a 408. So the rotating assembly is on back order… And since I’m doing a 408, I decided it would be best to go with 823 heads instead of the 317s. Found some on marketplace that I hope to have soon.

I’m not sure I’ve been more excited for anything in my life. Possibly equally, but not more.

View attachment 481336
View attachment 481337

How bad are your cam bearings? Or do you subscribe to the "as long as I don't look, they're fine" mantra?

lowh07 · Mar 27, 2026

Charlie207 said:
How bad are your cam bearings? Or do you subscribe to the "as long as I don't look, they're fine" mantra?

They seem to be in pretty good shape, but I’m replacing them. A few months ago I ordered the cam kit from Texas Speed, but that was for the 6.0 with 317s. I called and they’ll just exchange for the right cam. They make one for supercharged strokers so that should be ideal

Charlie207 · Mar 27, 2026

lowh07 said:
They seem to be in pretty good shape, but I’m replacing them. A few months ago I ordered the cam kit from Texas Speed, but that was for the 6.0 with 317s. I called and they’ll just exchange for the right cam. They make one for supercharged strokers so that should be ideal

It's interesting how they sell "packages" for all sorts of different engine upgrades (N/A vs. turbo vs. supercharger), but the dyno testing usually doesn't show any difference or significant gains per dollar for special boosted applications.. Head flow, ring gap, and good exhaust flow are the big ones.

I'm no expert, but it's just interesting to see the shift in understanding as more people share their dyno experiences.

lowh07 · Mar 27, 2026

Charlie207 said:
It's interesting how they sell "packages" for all sorts of different engine upgrades (N/A vs. turbo vs. supercharger), but the dyno testing usually doesn't show any difference or significant gains per dollar for special boosted applications.. Head flow, ring gap, and good exhaust flow are the big ones.

I'm no expert, but it's just interesting to see the shift in understanding as more people share their dyno experiences.

Yeah I’m definitely no expert either, so I’m just deciding to trust the experts. I’m sure a bunch of it is just marketing too.

Charlie207 · Mar 27, 2026

lowh07 said:
I’m sure a bunch of it is just marketing too.

Yeah, for sure it is.

A tuner from my old turbo-4 days would say to ignore all the marketing ****, and focus on making your N/A engine as good as possible first, and no matter what, it'll translate into a good boosted engine.

Tonyv__ · Mar 27, 2026

SpareParts said:
@lowh07 @Tonyv__
Maybe Tonyv could use the rods if you're going to toss them.

Appreciate you thinking about me. I don’t even have the capacity to think about that engine right now. Family stuff, added responsibilities. Yada yada yada, I won’t bore this thread with the details lol.

SpareParts · Mar 27, 2026

Update on my NP261HD Transfer case if anyone is watching.
Once i put my good 2.0 reading glasses on i did find some excessive wear.

The range fork has some pads molded onto it. The pads are nearly worn through and one side it is cracked. So replaced.

The range sleeve/gear is also worn on the teeth. Also replaced.

This is the input bearing. I can not find any printed specs for fit but the consensus is .020 movement in/out is perfect and at 0.70 the case is junk. Mine moves.030. I would shim it but the only shim i can find come as two shims and is $30. I ain't paying that and .030 will work fine. I could use JB Weld to take up the space but how long would that last?

Now im just waiting on parts as it seems some companies ship the slowest possible way they can find.

Atrevino0497 · Mar 27, 2026

mikez71 said:
Noticed no park lamps on left side, one tail bulb was out, fuse blown.
Old bulbs were about a year old, sylvania long life my ass!
Old bulb has dark spot, heat discolored the plug a little.. no obvious break in filament..

Swore I'd never buy sylvania again..
(LED taillights, dim, total crap. LED interior lights, ugly geen/blue color temp. Long life bulbs, don't last long at all!)

Go to Oreilly's, guess what the only bulb there? Syl-*****-vania..
Spent $37 for 25 15A fuses($13) and 2 tailbulbs. Guess I spent $20 on a pack of 2 bulbs!

-- DO NOT BUY SYLVANIA! ---- YOU WILL REGRET IT! --

I had the same exact problem but it was my passenger side drl bulb. I was going through them every 6 months. This last time though I noticed the contact on the bulb was melted and making intermittent contact. My connections are tight and no corrosion in the plug or shorts. I switched to the led style bulb and it’s been going strong for 8 months now. Sylvania has gone down hill and they charge an arm and a leg for bulbs that don’t even make it to burning out.

So now as bulbs have been burning I’m slowly switching to leds. Right now I have drl and license plate lights done. One set of bulbs at a time I guess.

My fog lights get used every night. Very helpful for seeing into ditches when watching for deer. That’s the only bulb I have yet to touch

Atrevino0497 · Mar 27, 2026

Joseph Garcia said:
This seems to be the year for pulling off door handles. I just replaced my rear passenger side door handle earlier this week.

I need to pull my driver rear door panel card off and find new clips for it. I got hit by a high schooler back in 2023 after she failed to stay in her lane on a curved road. She first made impact at my front bumper bounced off and back into me and while still holding the gas down.

My whole driver side got replaced and my back left tire was punctured, they also had to pull the center pillar back out and readjust the hinges on top of the striker plate

. I had just gotten it back from getting my alignment, tires rotated and was on my way back home to flush my coolant.

since getting the new door though I get a rattle in my back door and it’s more prominent now since the cold is here. It drives me nuts.

My local Chevy dealer has a brand new collision center. They did a wonderful job otherwise. I know there was a tsb many years ago with the door panel clips for this same reason. I’ll snag the part number off of it and give those a try. Otherwise I’ll put some foam in there and slap it back together again

Atrevino0497 · Mar 27, 2026

Sir_Hiro said:
Drivers side rear brake caliber is sticking..ofc its right after i put brand new powerstop pads on....so ordering up a set for both sides and the soft line.

Then gonna take it to a shop to have it bled cuz I have been unsuccessful and its had a spongey pedal since I bought it.

Also developed a belt squeal and exhaust mani leak. This winters been hell lol

It can be a bear bleeding the brakes without a vacuum pump. Having someone hit the brakes before you open the bleeder screw these days is a hit or miss and I’ve noticed the same thing. Spongy brakes, no issues with the vac. Best money spent and paid itself off the first time I used it

Charlie207 · Mar 28, 2026

Atrevino0497 said:
It can be a bear bleeding the brakes without a vacuum pump. Having someone hit the brakes before you open the bleeder screw these days is a hit or miss and I’ve noticed the same thing. Spongy brakes, no issues with the vac. Best money spent and paid itself off the first time I used it

I have the Motive brand version, but this one looks perfect, and comes with a brake fluid drain.

https://www.amazon.com/Orion-Motor-Tech-Compatible-Chevrolet/dp/B0FH9Z3H4R/130-2516352-0248258?pd_rd_r=5f099524-00e8-472c-b6a8-258e5b0d4d09&pd_rd_wg=3AdhY&pd_rd_w=cjAIu&pd_rd_i=B0FH9Z3H4R&psc=1&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWxfdGhlbWF0aWM=

SpareParts · Mar 28, 2026

One of the upgrades im doing is replacing the synchro friction band thing.
The OEM style is high metallic requiring ATF fluid. The new low metallic is designed to work with 5w30 synthetic motor oil.
Being all bearings, gears and a chain running 5w30 would only help with lubrication. Makes sense to me anyway.
This synchro is what enables shift on the fly 2H to 4H
Old on the left, new on the right.

89Suburban · Mar 28, 2026

Charlie207 said:
I have the Motive brand version, but this one looks perfect, and comes with a brake fluid drain.

https://www.amazon.com/Orion-Motor-Tech-Compatible-Chevrolet/dp/B0FH9Z3H4R/130-2516352-0248258?pd_rd_r=5f099524-00e8-472c-b6a8-258e5b0d4d09&pd_rd_wg=3AdhY&pd_rd_w=cjAIu&pd_rd_i=B0FH9Z3H4R&psc=1&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWxfdGhlbWF0aWM=

Yup, I use mine very year or 2 to replenish the brake fluid.

SpareParts said:
One of the upgrades im doing is replacing the synchro friction band thing.
The OEM style is high metallic requiring ATF fluid. The new low metallic is designed to work with 5w30 synthetic motor oil.
Being all bearings, gears and a chain running 5w30 would only help with lubrication. Makes sense to me anyway.
This synchro is what enables shift on the fly 2H to 4H
Old on the left, new on the right.

View attachment 481489

This is interesting stuff thanks for taking the time to share.

Sir_Hiro · Mar 28, 2026

Charlie207 said:
I have the Motive brand version, but this one looks perfect, and comes with a brake fluid drain.

https://www.amazon.com/Orion-Motor-Tech-Compatible-Chevrolet/dp/B0FH9Z3H4R/130-2516352-0248258?pd_rd_r=5f099524-00e8-472c-b6a8-258e5b0d4d09&pd_rd_wg=3AdhY&pd_rd_w=cjAIu&pd_rd_i=B0FH9Z3H4R&psc=1&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWxfdGhlbWF0aWM=

I might buy that. I could just let all 4 gravity bleed for a day since I have 4 other cars to drive...but I do like suction power...HA

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