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

I'm doing my typical engineer "paralysis by analysis" for installing an auxiliary transmission cooler and I've run across some interesting stuff.

Before I say what that is, yes Tru-Cool 40K cultists, I've heard your proselytizing plenty and know The Good Word of your sacred installations!

The first thing is something that I've always known and assumed others did too, but I'm apparently mistaken in my assumption. A surprising number of folks don't understand that the in-radiator transmission cooler is on the "cooled" outlet side of the radiator, not the "hot" inlet side of the radiator. They think and a few tech articles imply the in-radiator transmission cooler being in coolant means it is in coolant that's at the engine's operating temperature -- IT IS NOT! It's not in contact with coolant coming out of the engine, it's in contact with coolant going back into the engine.

The second thing is that the traditional "knowledge" that the transmission fluid is warmed up more quickly by being in the coolant. However, this doesn't apply for ambient temperatures of ~80°F and above (and undoubtedly lower, but how low I don't know because I haven't tested at those temperatures). I know this because I have installed thermocouples on the radiator outlet, transmission "hot" line as it goes into the radiator, and the transmission "cooled" line as it exits the radiator. The transmission "hot" and "cooled" temperatures always climb faster than the radiator "out" temperature, so the transmission fluid is never being warmed in these conditions.

The pics attached below show a Torque Pro screenshot and a picture of the thermocouple unit, taken within a few seconds of each other. This is in moderate stop-and-go traffic, and ambient is a couple of degrees lower than the intake temperature; from top to bottom, the thermocouple readouts are: radiator outlet, trans hot in, trans cool out. Before anyone asks why the trans temp on Torque Pro and the thermocouple trans hot temperatures don't match, I've found that when in traffic the trans temp is always higher, but when in steady-state on the highway, they are very close.

89Suburban said:

I'mma be lookn for yo ass too gangsta. I'm gonna cover all of NJ south to north, then hop up into your area. Make my way from there out to KC to see that mamaluke @07Burb. Then shoot down to OK, Louisianna, up to Tenn to see that sorry ass @pwtr02ss and VA @Geotrash. Come back up 81 into PA and back home.

Click to expand...

What? You're not going to come into the Northeast and visit me too? WTF!

leveled, tinted. 5% all around 20% full windshield. Geoshield Pronano Ceramic(so yes, you can see perfectly fine from the inside) pic below to prove exactly that
6 high mod.
dod/afm turned off.
changed rims a bunch. currently on stocks & super swamper m16's (way better tire than the mud grappler IMO) however the black/chrome mavericks (20x12's) looked the best (paid $350 for them lol)





from the outside


inside looking out



6 high mod - prob the best 25 dollars i've spent on it

Scrappycrow said:

I'm doing my typical engineer "paralysis by analysis" for installing an auxiliary transmission cooler and I've run across some interesting stuff.

Before I say what that is, yes Tru-Cool 40K cultists, I've heard your proselytizing plenty and know The Good Word of your sacred installations!

The first thing is something that I've always known and assumed others did too, but I'm apparently mistaken in my assumption. A surprising number of folks don't understand that the in-radiator transmission cooler is on the "cooled" outlet side of the radiator, not the "hot" inlet side of the radiator. They think and a few tech articles imply the in-radiator transmission cooler being in coolant means it is in coolant that's at the engine's operating temperature -- IT IS NOT! It's not in contact with coolant coming out of the engine, it's in contact with coolant going back into the engine.

The second thing is that the traditional "knowledge" that the transmission fluid is warmed up more quickly by being in the coolant. However, this doesn't apply for ambient temperatures of ~80°F and above (and undoubtedly lower, but how low I don't know because I haven't tested at those temperatures). I know this because I have installed thermocouples on the radiator outlet, transmission "hot" line as it goes into the radiator, and the transmission "cooled" line as it exits the radiator. The transmission "hot" and "cooled" temperatures always climb faster than the radiator "out" temperature, so the transmission fluid is never being warmed in these conditions.

The pics attached below show a Torque Pro screenshot and a picture of the thermocouple unit, taken within a few seconds of each other. This is in moderate stop-and-go traffic, and ambient is a couple of degrees lower than the intake temperature; from top to bottom, the thermocouple readouts are: radiator outlet, trans hot in, trans cool out. Before anyone asks why the trans temp on Torque Pro and the thermocouple trans hot temperatures don't match, I've found that when in traffic the trans temp is always higher, but when in steady-state on the highway, they are very close.


View attachment 489026View attachment 489027

Click to expand...

one of the differences is you are reading external vs internal on the transmission temp, regardless the temps look accurate enough
without a thermal regulator it's going to be all over the place regardless. I have seen mine go as low as 80deg in below freezing weather, that was on a road trip and is not normal weather I encounter all the time so I have no need for a regulator.
I know if let it sit and idle parked for a extended period of time in moderately warm weather (ac on) it will pretty much go up to and sit right at 180deg all day long.
the bottom line is if you follow severe duty maintenance on the transmission fluid, then the fluid will always be able to do it's job. heat kills it, that's a fact. I don't care what "the manual" says.
If anyone goes out right now and pull out the transmission fluid dipstick and wipe it on a white paper towel, if the fluid is not a pretty light red/pink, then it needs to be changed.
brown is bad, dirt color is bad. dark red is questionable.
just like your brake fluid should not be BLACK, brake fluid is almost clear..... black indicates it's burnt and likely has moisture in it which reduces the boiling point.

I've been running with a semi-OEM CAI setup for a while, since the gasket material between the air cleaner box and the passenger inside quarter panel had rotted away. I remembered a post a few years ago, I think by @Doubeleive , that said that he used some Frost King weather-stripping foam as a replacement gasket material. So, I gave it a try, and it works!

I used the 1 1/4" x 1 1/4" foam weather-stripping and cut pieces to go around the circumference of the two openings. Then, I epoxied the foam strips to the air cleaner box, and to each other.

Like an idiot, I forgot to take a photo of the gasket side of the bottom half of the air box, before installing it, and I was not going to remove it again, just for a photo. I did take a few photos after the bottom half of the air box had been installed.

Joseph Garcia said:

I've been running with a semi-OEM CAI setup for a while, since the gasket material between the air cleaner box and the passenger inside quarter panel had rotted away. I remembered a post a few years ago, I think by @Doubeleive , that said that he used some Frost King weather-stripping foam as a replacement gasket material. So, I gave it a try, and it works!

I used the 1 1/4" x 1 1/4" foam weather-stripping and cut pieces to go around the circumference of the two openings. Then, I epoxied the foam strips to the air cleaner box, and to each other.

Like an idiot, I forgot to take a photo of the gasket side of the bottom half of the air box, before installing it, and I was not going to remove it again, just for a photo. I did take a few photos after the bottom half of the air box had been installed.

View attachment 489050

View attachment 489051

View attachment 489052View attachment 489053

Click to expand...

I don't think it was me but ya any hardware store will have various size/thickness of foam padding insulation, etc. basically weatherstripping.
if they don't have the size you need you can cut it down or double it up, either way....
beats a $100 "part" from the dealer.

Joseph Garcia said:

I've been running with a semi-OEM CAI setup for a while, since the gasket material between the air cleaner box and the passenger inside quarter panel had rotted away. I remembered a post a few years ago, I think by @Doubeleive , that said that he used some Frost King weather-stripping foam as a replacement gasket material. So, I gave it a try, and it works!

I used the 1 1/4" x 1 1/4" foam weather-stripping and cut pieces to go around the circumference of the two openings. Then, I epoxied the foam strips to the air cleaner box, and to each other.

Like an idiot, I forgot to take a photo of the gasket side of the bottom half of the air box, before installing it, and I was not going to remove it again, just for a photo. I did take a few photos after the bottom half of the air box had been installed.

View attachment 489050

View attachment 489051

View attachment 489052View attachment 489053

Click to expand...

It was @iamdub (Chris) who posted the air filter box re-foam.

Fless said:

It was @iamdub (Chris) who posted the air filter box re-foam.

Growing up doesn't have to suck

I had some 20K-mile LS6 springs (yellow) from some Z06 heads I had for a past project. I got the 2600-2800 converter. I think it's the famed I-6 Trailblazer converter, but with an upgraded clutch and slightly higher stall. The rep said my Tahoe should still roll if I idled in gear with my...

www.tahoeyukonforum.com

Click to expand...

Who dat? Name sounds familiar.....

Fless said:

It was @iamdub (Chris) who posted the air filter box re-foam.

Growing up doesn't have to suck

I had some 20K-mile LS6 springs (yellow) from some Z06 heads I had for a past project. I got the 2600-2800 converter. I think it's the famed I-6 Trailblazer converter, but with an upgraded clutch and slightly higher stall. The rep said my Tahoe should still roll if I idled in gear with my...

www.tahoeyukonforum.com

Click to expand...

Super! Thank you for identifying who had the original idea.

installed this thing, on the ground. it wouldn't have been hard if it had of been on a lift, but this was a huge PITA from being on my back!!! not to mention, it was all OEM stuff on there, so it's been stuck for (you might as well say) 20 years.

Scrappycrow said:

I'm doing my typical engineer "paralysis by analysis" for installing an auxiliary transmission cooler and I've run across some interesting stuff.

Before I say what that is, yes Tru-Cool 40K cultists, I've heard your proselytizing plenty and know The Good Word of your sacred installations!

The first thing is something that I've always known and assumed others did too, but I'm apparently mistaken in my assumption. A surprising number of folks don't understand that the in-radiator transmission cooler is on the "cooled" outlet side of the radiator, not the "hot" inlet side of the radiator. They think and a few tech articles imply the in-radiator transmission cooler being in coolant means it is in coolant that's at the engine's operating temperature -- IT IS NOT! It's not in contact with coolant coming out of the engine, it's in contact with coolant going back into the engine.

The second thing is that the traditional "knowledge" that the transmission fluid is warmed up more quickly by being in the coolant. However, this doesn't apply for ambient temperatures of ~80°F and above (and undoubtedly lower, but how low I don't know because I haven't tested at those temperatures). I know this because I have installed thermocouples on the radiator outlet, transmission "hot" line as it goes into the radiator, and the transmission "cooled" line as it exits the radiator. The transmission "hot" and "cooled" temperatures always climb faster than the radiator "out" temperature, so the transmission fluid is never being warmed in these conditions.

The pics attached below show a Torque Pro screenshot and a picture of the thermocouple unit, taken within a few seconds of each other. This is in moderate stop-and-go traffic, and ambient is a couple of degrees lower than the intake temperature; from top to bottom, the thermocouple readouts are: radiator outlet, trans hot in, trans cool out. Before anyone asks why the trans temp on Torque Pro and the thermocouple trans hot temperatures don't match, I've found that when in traffic the trans temp is always higher, but when in steady-state on the highway, they are very close.


View attachment 489026View attachment 489027

Click to expand...

is there a question in there somewhere?

j91z28d1 said:

is there a question in there somewhere?

Click to expand...

What's the title of this 2674-page-long thread? Do all of the 53,460 posts before mine that aren't replies to others' posts have "a question in there somewhere"?

Scrappycrow said:

What's the title of this 2674-page-long thread? Do all of the 53,460 posts before mine that aren't replies to others' posts have "a question in there somewhere"?

Click to expand...

oh, totally didn't read it that way and honestly I just click on the notification bell and read along, usually while doing some run else at the same time.


are you buying the 40k cooler or no?

changed these things. they were at .60...set the new 1's to .40.

j91z28d1 said:

oh, totally didn't read it that way and honestly I just click on the notification bell and read along, usually while doing some run else at the same time.


are you buying the 40k cooler or no?

Click to expand...

Ha, no worries!

Nope, I'm going with a stacked-plate, along with a remote filter mount and this inline thermostat (haven't decided whether I'll go with a 145°F or 165°F, but a rebuild kit with a different setting is only $14). This more-square 25-row stacked-plate has the same BTU rating as the Tru-Cool 40K (46K vs 45K BTUs, respectively), but is more "square," which will facilitate a shroud/fan combo should I decide to fabricate/install that later; it's also much easier to change sizing because the fitting spacing stays the same as you go up in number of plates, which would matter since I'll be fabricating hard lines.

commercialfshrmn said:

changed these things. they were at .60...set the new 1's to .40.
View attachment 489114
View attachment 489115

Click to expand...

looks like you might need a catch can and new drivers side updated valve cover if not already installed. probably sucking some excess oil fumes in.

Doubeleive said:

looks like you might need a catch can and new drivers side updated valve cover if not already installed. probably sucking some excess oil fumes in.

Click to expand...

they're still the 07 OEM covers.GM did a recall/update?

catch , eh? best value for the $? not looking to spend too much

commercialfshrmn said:

they're still the 07 OEM covers.GM did a recall/update?

catch , eh? i'll order one now. best value for the $? not looking to spend too much

Click to expand...

yes there was a update to them in 2010, just order a LEFT one for a 2013 on rockauto the oem one is about =$65-70, there's a 5% discount code posted on the main forum page, tons of catch cans on amazon, take your pick

Doubeleive said:

yes there was a update to them in 2010, just order a LEFT one for a 2013 on rockauto the oem one is about =$65-70, there's a 5% discount code posted on the main forum page, tons of catch cans on amazon, take your pick

Click to expand...

never got that in the mail. all i ever get is the recall for the air-bags. can i take it to the local dealership & have them fix it under recall?

commercialfshrmn said:

never got that in the mail. all i ever get is the recall for the air-bags. can i take it to the local dealership & have them fix it under recall?

Click to expand...

it's not a recall, it's just a redesign to help prevent excessive oil consumption