Trans cooler and upgrade radiator

[Caman96]

I installed a factory cooler, plumbed factory style and replaced single core radiator with duel core. Even towing in 100° plus temps, watching coolant temperature in real time it never exceeds 200°. It might tick over 195° for a minute but immediately comes back. Transmission typically around 145-150° on highway, 170-175° around town. Factory system works fine for me, original steel fan as well.

 

[Logan R]

Yes sir

Ok sounds good, so I can just route it from rad to external cooler than to radiator and it’ll feed through the external cooler to the trans without me having to route another line straight to the trans?

 

[Insert Quarter]

Ok sounds good, so I can just route it from rad to external cooler than to radiator and it’ll feed through the external cooler to the trans without me having to route another line straight to the trans?

Radiator outlet to cooler then the cooler outlet to transmission - The instructions have a picture - Figure "B" In-Series Installation

 

[L31MaxExpress]

Ok sounds good, so I can just route it from rad to external cooler than to radiator and it’ll feed through the external cooler to the trans without me having to route another line straight to the trans?

I would route it from the radiator cooler to the auxiliary cooler then back to the trans, using as much of the OE hardline as possible. Put the coolers in series, not parallel. Radiator coolet then auxiliary cooler. That is how GM setup all the OE coolers. Trans fluid enters the top port of the radiator, then it comes out the bottom port to the aux cooler, then it goes back to the transmission.

 

[Schurkey]

Trans fluid enters the top port of the radiator, then it comes out the bottom port to the aux cooler, then it goes back to the transmission.

Sure?

I thought the trans cooler flow within the radiator was opposite to the radiator "water" flow.

Trans fluid enters the bottom port, comes out the top port.

'97 C/K service manual page 7A14D-22 and 23 seems to support "opposite" flow--the discharge (back to the transmission) is the upper fitting on the radiator.

Am I misunderstanding?

When I worked at The Bus Company, we were told that reverse-flow through a cooler (Hot oil goes one direction, "coolant" flows the opposite direction.) resulted in ~10% better efficiency/effectiveness.

With an in-radiator-tank heat exchanger, the hot trans fluid would enter nearest the lower rad hose fitting, and the "cooled" trans fluid would exit nearest the upper rad hose fitting.

 

[Logan R]

I am almost 100 percent sure your right, when I did my fluid change I ran the engine to pump out as much trans fluid as possible and it came out the top port on the rad not the bottom.

 

[Insert Quarter]

I've seen both, but personally, I would just follow the instructions that come with the cooler.

IN-SERIES INSTALLATION
1. Locate the steel lines coming from the transmission to the radiator (most commonly to side tank or bottom). Determine which is the return line by running the engine for 2 minutes, then feeling the lines near the radiator. The cooler of the 2 lines is the return line. Loosen the fitting where the return line enters the radiator, as shown in Figure B, and separate the steel line from the radiator.

 

[L31MaxExpress]

Sure?

I thought the trans cooler flow within the radiator was opposite to the radiator "water" flow.

Trans fluid enters the bottom port, comes out the top port.

'97 C/K service manual page 7A14D-22 and 23 seems to support "opposite" flow--the discharge (back to the transmission) is the upper fitting on the radiator.

Am I misunderstanding?

When I worked at The Bus Company, we were told that reverse-flow through a cooler (Hot oil goes one direction, "coolant" flows the opposite direction.) resulted in ~10% better efficiency/effectiveness.

My 83 G20, my 97 Express and my 99 Tahoe all flow down. The upper port was the inlet from the factory. All 3 started life without the auxiliary cooler. The factory 4L80E lines, atleast the later ones on the Van and Tahoe now that they have 4L80Es are setup the sams way too, auxiliary cooler connects to the bottom of the radiator.

I am also confused as to how putting the outlet in hotter fluid would cool better than having the outlet in cooler fluid. That is exactly opposite of basic thermodynamics. Heat moves from higher heat energy to lower heat energy and the higher the temperature delta, the quicker the transfer.