Th400 transmission cooler for towing

[Supercharged111]

Electric fans are a grate swap, but like everything else, they need to be big enough to do the job and a little extra is a plus. I have a set of Cadi Deville fans on my truck. Grate swap. That 350 never over heats. 454 s have always been known to run hot. More colling is a good thing.

GenV is known to run hot. My supercharged dually is rock solid even loaded to the gills.

Gen V

That was my guess. You sure you don't have an external cooler? The mechanical fans suck at a standstill but are excellent if you're moving and redlined.

 

[89_C3500_Larry]

GenV is known to run hot. My supercharged dually is rock solid even loaded to the gills.



That was my guess. You sure you don't have an external cooler? The mechanical fans suck at a standstill but are excellent if you're moving and redlined.

I'm sure, the lines come out of the transmission and go straight to the radiator. That's the only cooler on the system

 

[Supercharged111]

I'm sure, the lines come out of the transmission and go straight to the radiator. That's the only cooler on the system

That's insane. Definitely get the most monstrous cooler you can fit on that thing without a lockup converter.

 

[stutaeng]

The very early GMT 400s 2500/3500 I think are a little weird like that. I've read here that some 3500s even had vaccum-assist brakes and semifloat axles!

These were the transition years between square bodys and GMT400. It's pretty crazy when you consider that the last square body RV series up to '91 got the 4L80 but early GMT 400s got the TH400, no? Backwards of what you'd think.

 

[Supercharged111]

And some of the TBI trucks got engine oil coolers and seemed more generous with the 4.10 gears and whatnot.

 

[1989GMCSIERRA]

One of the largest coolers you can get are the coolers off a 6.0 Ford diesel. I bought a 32 row for my 7.3. It’s literally about 24x24 inches. Its really about the size of a small car radiator. It’s 3x the size of the stock 7.3 trans cooler which is decent size in itself. But the new cooler is 3x that size. I’ve installed a few of these on friends trucks and they all said the temp never gets above 175. And these guys tow. None of the coolers have auxiliary fans. They rely on the belt driven clutch style fan which will pull more air than any electric fan.
Check to see if your clutch isnt going bad, I had that happen once and I tore the damn cooling system apart till I thought to check the clutch
That Ford style cooler also comes with mounting ears. They can be bought for about 160-300 bucks depending on where you look. And they have 1/2 inch in and out nipples.

I usually run my coolers separate. If I lived in a colder climate I would run it as a in line or secondary to the stock in radiator cooler.

 

[Supercharged111]

24x24 trans cooler? 'Murica!!!

 

[df2x4]

Just FYI, the TruCool M7B is a great upgrade that will fit in the factory external cooler location. You can even use the factory mounting brackets if you trim them down a little. Here's a thread on that process, you'd need to add the lines since your truck never had an external cooler.

https://www.gmt400.com/threads/how-to-factory-auxiliary-trans-cooler-upgrade.18104/