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Looked in the GM Service manual and they have the additional transmission cooler plumbed from the bottom line for the 4L60-E transmission.
If you take a closer look at the diagram, it has to be about 50 years old. Just look at that old fashioned oil can and frisbee shaped air filter + carb setup. They probably had to plumb the cooler in that way.
Modern coolers have a bypass which allows the transmission to get up to operating temperature quicker.
If you take a closer look at the diagram, it has to be about 50 years old. Just look at that old fashioned oil can and frisbee shaped air filter + carb setup. They probably had to plumb the cooler in that way.
Modern coolers have a bypass which allows the transmission to get up to operating temperature quicker.
Appreciate the detailed explanation and the diagrams. I did notice the carb setup with the air cleaner but figured the transmission plumbing was the same. I'm glad I left the cooler hookup to the end,
Thanks
Ron
Let us know how it turns out in the end, and maybe post a pic or two.
Do you have a way to measure ATF temps?
I bought a gauge that goes inline with the return transmission line. Last thing to do before adding the fluid.
What would be the correct range of temps to look for?
A gauge might be overkill, because after you install a cooler you just stop caring. You might be able to read it with an OBD gizmo.
The fluid temperature depends on where in the circuit you measure it, the ambient temperature outside, airflow past the cooler etc. (so don't overthink it). I think GM puts the temperature sensor near the pump, which means it's measuring the temperature of the fluid coming from the pan (probably where it's most stable). Cruising temp is in the neighborhood of 90-100C / 190-210F. When it works hard it might be around 110C/230F , but it could peak even higher - 120C/250F. (crawling up a hill). I think it's normal to see high temps like that for short periods of time, but of course you don't want it to do that a lot.
When I installed a cooler in my old van (Long Tru-Cool LPD 4590) I had a drastic reduction in temperature. Even when I pushed it hard up a steep hill on the highway, the pan temperature would get around 55C/130F above ambient, and I couldn't get it to budge any higher. That's a reduction of around 30C/85F.
Transmission, cooler and radiator are now installed. After a bit of a hiccup, the transmission is working well. Wondering if the tranny temp gauge can be installed in the pressure port, over the safety neutral switch?
Thanks
Ron
Some people do that. It's a 1/8" NPT thread. Don't use teflon tape.
I don't think it's the best way to do it. (A) there is no flow. The port was intended for testing pressure. (B) it's at the output of the torque converter, which means it will read really high, which isn't very meaningful.
If you can, get an OBD tool to read it. My Scangauge II (using the xgauge function) was able to read the built-in NTC thermistor of the 4l60-E tranny in my 2000 Astro, so it should be possible on yours.
October 31st, 2018, 4:42 PM
