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

[j91z28d1]

My first Cold Case Radiator (original design) lasted 2 years/30,000 miles.

Replaced under warranty with 2nd design in 2022, no issues as of yet.

Mine was leaking into the tray under the Radiator as well and appeared to possibly have some cracking around the mounting posts on the bottom and maybe where the tubes met the tank at the bottom, but couldn't verify exactly.

View attachment 425020View attachment 425022View attachment 425023

good lord the welds on that thing..

OK, I got why they leak. it's a quality control issue would be my guess

 

[iamdub]

Yeah, I thought for a while that I had the AGM charging problem solved with a new alternator, but it's super clear to me now that AGM is not the right choice for these rigs because the software governs the battery management, and it was written for flooded lead-acid batteries. Putting an AGM battery in one of these is throwing good money away. I have been through three AGM batteries in the last 5 years on these rigs. The first two died within months so I chalked it up to defective batteries.

I have 4 year old agm's (interstate) in the yukon and the silverado and both are fine so far...
4 years around here is about max life so I have been watching for signs of them getting weak but no signs of that yet

Mine will be installed one year this Cinco de Mayo. So far, no issues. Perhaps we could compare you two with how your AGMs were used? Like, did the vehicles often sit for a few days or a week or whatever between crankings or were they used daily, etc.? Just trying to see if there are some common denominators one could be mindful of.

 

[Doubeleive]

Mine will be installed one year this Cinco de Mayo. So far, no issues. Perhaps we could compare you two with how your AGMs were used? Like, did the vehicles often sit for a few days or a week or whatever between crankings or were they used daily, etc.? Just trying to see if there are some common denominators one could be mindful of.

We have 3 vehicles so it might get used daily or might sit for 10 days or anything in between
sometimes it depends on how much gas each one has in it and if I am busy it might just sit there until I have time to go fill it up
I ran the odyssey's for a long time since way back when they used to make them for sears, but seemed like the quality went downhill and they wouldn't even make it out of warranty anymore. 2 interstates from costco for the price of 1 odyssey and it has been 4 years without a hiccup

 

[Geotrash]

Mine will be installed one year this Cinco de Mayo. So far, no issues. Perhaps we could compare you two with how your AGMs were used? Like, did the vehicles often sit for a few days or a week or whatever between crankings or were they used daily, etc.? Just trying to see if there are some common denominators one could be mindful of.

Our 2012 has the cold case and often sits for several days to 2 weeks between drives. It’s our towing rig so it doesn’t get used much. If it’s been a while I’ll drive it long enough to get the oil fully warmed up. Say, 30 miles on the highway or so. It has an AGM battery in it as well that’s 4 years old also. Same brand and model as the one I replaced in the 2007.

So our 2007 is the one that needed a battery and that gets driven every other day at the outside and most of the time daily.

 

[mikez71]

Installed factory trans cooler, I did them after motor mounts, no benefit to having the mounts out of the way.
Pulled hose ends/lines from the backside to the front. Had to remove bumper cover (super easy!) to move the bumper bracket to get the lines through in front.

drilled new holes for the cooler bracket, then realized I just needed to push the bracket further to reach existing holes.. Oops!

 

[89Suburban]

Installed factory trans cooler, I did them after motor mounts, no benefit to having the mounts out of the way.
Pulled hose ends/lines from the backside to the front. Had to remove bumper cover (super easy!) to move the bumper bracket to get the lines through in front.

drilled new holes for the cooler bracket, then realized I just needed to push the bracket further to reach existing holes.. Oops!

No pics and documentary?

 

[kbuskill]

Is that a petcock valve I see on there for draining the coolant?! Why didn't GM do this?

Yes it is, GM saved nickles and dimes on the GMT900 trucks, they got rid of lots of little things the previous generation trucks had. GMT900s (at least the Tahoe/Yukon/Suburban) had NO Under hood light, NO cabin air filter, NO lights in the door panels, NO pet **** in radiators, NO rear window release button inside, NO under dash lights, probably more stuff I am forgetting.

 

[Grady_Wilson]

The lack of a cabin filter always amazed me.

 

[mikez71]

No pics and documentary?

Well if you like, but it's boring and fairly straightforward.
I can snap pics of the routing eventually, and will have bumper off again, but my camera is down at the moment..
So here's a quick rundown..

I got GM lines from Amazon, $90 for the first one (2 lines), and $20 for the second one currently..
https://a.co/d/1OvcynD 25999420 Automatic Transmission Fluid Cooler Inlet and Outlet Line (transmission to lower radiator, return from cooler to transmission)
https://a.co/d/htPJBIJ 15779543 Automatic Transmission Auxiliary Fluid Cooler Inlet Line (upper radiator to cooler)

20880895 Automatic Transmission Auxiliary Cooler

I got a 'TYC' cooler (made in Taiwan) from rockauto for $60 ($110 cheaper than GM)

More Information for TYC 19031

Needed bolts for
1. the trans cooler itself (2x 10mm head size screws, same screws that hold the bumper bracket on are perfect.)
2. cooler lines bracket to engine block (1x 10mm head size screw, short)

Everything bolts in, only things you need to remove are
1. under cover(s) (4-8 bolts)
2. old transmission cooler lines
3. front bumper (8? bolts on top, 2 on bottom. 2 screws and 2 pushpins on each fender liner, unplug foglights)
4. front bumper bracket (6 bolts)

I snaked the hose front to back, and it will snake through there if you keep adjusting the ends
Then at the front the bumper bracket had to be loosened and the lines swung up into place behind it, there is a notched section where they fit through
Cooler slides right onto existing support, just to the right of a temp sensor.
Plastic on temp sensor VERY brittle, touched and broke the mounting on mine. I left it hanging in a corner.

 

[89Suburban]

Stumbled across this broken bolt while checking the oil. Guess I am part of the club now. Not leaking though.