I have a 40k trans cooler in my 03 z71. The 4l65 is built billet input output wide band super servo the billegal pump vanes the sonnax input drum. It also has the deep pan with the cooling tubes running through it and a bowler 3400 stall. My Trans wants to run between 170 and 200 degrees. That is way hotter than it should even at cruise at 70 it stays warm. I have a dedicated fan just 4 the cooler. The lines are -6 an. I just can't figure out how to keep it cool. This is the second converter I've had too. Same issue with both. The fluid isn't burnt and Ivery probably got 4000 miles since the last build

 

Bypass the radiator and test the Trucool for proper flow (if one side is warm and the other is not then it's probably plugged).

The dedicated fan is just wasting 40% of your cooler surface (only the outer edges of the fan blades see flow). Your radiator fan will create sufficient draw if you place it in the grille area.

 

Yeah it is the old cooler I bypassed the radiator a long time ago the fan has actually helped a little probably dropped the temp ten degrees
thanks

 

170-200 is perfectly safe. I don't really see the issue here.

 

I have seen 211 at the track and as high as 205 in traffic coolant stays below 200

 

My trans is a built 4l60E built to best possible 4L65E with all billet internals, Circle D 3200 278 mm lock-up, True cool 40K in series with radiator and Dearle 2+ qt. pan with turbulator cooling, Dearle 180* thermo. and monitor it with Autometer mechanical trans temp gauge. Barely gets off the pin, (150-160*) in winter.

Hot summer day(90-95*), towing 6x12 tandem enclosed trailer with Bagger and softail aboard and I see 175-180* stop and go. On the highway at 70mph I see 165-170*

This has been verified with 2 new Autometer gauges. Couldn't believe the first one so I "borrowed" a second one, as well as boiled water and verified with pyrometer. Also seems too cool to be true!

 

I have the dearle pan where did you get the t Stat

 

It's a Dearle brand accessory. Thought installing it would help the trans get up to a reasonable op temperature in the winter. Good plan it turns out but trans still runs at 155-160, normal every day driving.

 

Yeah mine runs 180 daily but if it's hot out it runs about 205 I have seen 215 at the track