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

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Charlie207

Full Access Member
Joined
Apr 13, 2021
Posts
1,526
Reaction score
2,937
Location
LFOD, New Hampshire
For the Yukon, I exchanged 1 gal of ATF before I change all the fluid and filter.
Current trans fluid has 62K miles, 125K total. I removed the upper cooler line and used a fitting attached to a hose into a bucket.

View attachment 406509

Fluid was slightly dark but still had some red tint and smelled good.

My plan is to let the new fluid work around for a week and then change the filter along with about 3-4 gallons of fresh fluid.

Too much of a pita to drop the pan in short order, my thinking is if any cleaning is done the new filter won't get too contaminated, maybe dirty it up a bit this week with the 1 gal change.
I don't think swapping out a gallon of fluid will make any difference if you didn't drop the pan, clean it out, and swap the filter. Unless you do this every time you change the engine oil.

You just made the entire system slightly more red, but left the gunk in the filter and pan to circulate.
 

dkad260

Full Access Member
Joined
Jul 21, 2019
Posts
373
Reaction score
376
I don't think swapping out a gallon of fluid will make any difference if you didn't drop the pan, clean it out, and swap the filter. Unless you do this every time you change the engine oil.

You just made the entire system slightly more red, but left the gunk in the filter and pan to circulate.

Correct.

My plan is to let the new fluid work around for a week and then change the filter along with about 3-4 gallons of fresh fluid.

I don't want to change all the fluid at once then leave it alone. Any small cleaning or varnish removal will hopefully get caught in the old filter during this week.
 

j91z28d1

Full Access Member
Joined
Feb 28, 2022
Posts
2,837
Reaction score
3,389
cooling system stuff kinda sucks haha. good thing I'm not a flat rate guy, I'd be broke.


I'm a bit surprised it calls for 17qt and I only got 12qt in it, even draining the block and blowing out the heater core lines. oh well, maybe the spec is wrong for these trucks.

I did notice these hybrids have 5/8 tranny lines running to a front mount cooler. nothing in the radiator end tanks. I caught a comment in a online manual somewhere saying the electric motors in the tranny can make a lot of heat. I guess gm didn't play with tranny cooling. never seen tranny lines that big even in big trucks. front mount cooler is almost an inch thick, size of the radiator, split in the middle. bottom half is tranny, top is hybrid inverter cooling system. kinda wild. I guess that's why it normally runs in the 130s and max I've seen towing is 167.

water pump weep hole was clean, hoses all looked and felt good. if it wasn't for the stupid quick connect T's. I'd say these cooling system would outlast the trucks. kinda felt silly changing stuff. I think I'll throw the old parts on a shelf, my luck the new stuff will fail. haha
 

RooTBeeRthe1st

Full Access Member
Joined
Jul 11, 2018
Posts
1,083
Reaction score
2,457
I saw on the national news that a lot of areas in SoCal were worried about flooding and were filling sandbags. Also worried about mudslides/landslides if too much rain.

I always thought Cali would slide into the ocean due to an earthquake, but it might be a tropical storm
They're actually was a five point something earthquake in Ojai this afternoon too
 

Charlie207

Full Access Member
Joined
Apr 13, 2021
Posts
1,526
Reaction score
2,937
Location
LFOD, New Hampshire
I was getting tired of the cone filter on my truck, so I swapped the factory airbox back in. I cut down the aftermarket pipe, and used that to free up some space vs. the factory plastic mess.

ZgQiu94.jpg

Had to lop off a fair bit of tube to work with the factory accordian connector, which luckily worked as a reducer from the larger OD aluminum tube. (I was worried this conversion wouldn't work for a minute there...) It was a PITA to get that accordian connector off the OEM plastic intake; it was glued on pretty good.

lTazL7Y.jpg

But.... it went together. Not the prettiest "mod", but at least I get the better filtration of the factory air filter. Probably was a waste of $100, but the cone filter was pretty to look at, until it wasn't.

AXNyCt4.jpg

Squirted off the MAF sensor while I was swapping it back to the OG airbox location.
 

Charlie207

Full Access Member
Joined
Apr 13, 2021
Posts
1,526
Reaction score
2,937
Location
LFOD, New Hampshire
after a tank and half of e85 my mpg only dropped from 11.7 to 11.2 but mine seems to be really slow to change unless I clear it out completely
How noticeable is E85 vs. 87, or E85 vs. 93 octane? It's not available anywhere in my state, and I'm curious about how many furious ponies I'm missing out on.
 

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
25,461
Reaction score
37,819
Location
Stockton, Ca.
How noticeable is E85 vs. 87, or E85 vs. 93 octane? It's not available anywhere in my state, and I'm curious about how many furious ponies I'm missing out on.
I have my foot in this thing all the time and I honestly cannot tell any difference on the e85 versus 92, maybe, maybe a pinch more umph.. maybe. I am still trying it out, but so far nothing that makes me go ooooooh. other than it's a dollar a gal cheaper.
 

Forum statistics

Threads
131,411
Posts
1,850,604
Members
95,503
Latest member
SBRKPRO
Top