Tranny line which is which?

adirondack · June 19, 2003

Im trying to install a tranny temp gauge on 2001 Sierra 5.3 and need to know how you determine which line to the factory (radiator) cooler is the hot side and which is the cool side. I cant seem to tell by touching as they both feel about the same.

Thanks.

SFPegasus · June 19, 2003

Geez, why don't you just get a new cluster that already has the tranny temp gauge in it? All the sensors and wiring are already in place - it's just plug 'n play!

The only thing you need to do is have your mileage programmed into the new cluster - about $35.

americanmuscleman · June 19, 2003

Are you thinking of installing a temp sender into the output line of your tranny? If you are, you might think about screwing the temp sender into the test port on the side of the tranny. Its on the driver's side above the shift linkage.

Just an idea

I've forgotten which line is the input and output. Let me check.

americanmuscleman · June 19, 2003

The top line on the tranny is the output line, the bottom the input.

Here's a picture of the test port on the side of the tranny if you want to install it there. This is on a 95' Z28, but the tranny is the same 4L60E, and you'll find the test port in the same location.

BadBowtie · June 21, 2003

You want to monitor the temp in the outgoing line, it doesnt matter what it is in the case. Many gauge mfgrs say to put it in the pan, but you are more concerned with what the hottest temp will be (found in the cooling line that goes into the radiator)

-John

robsawatsky · June 21, 2003

I've got a 2000 K2500 Crew Cab (old body style) with the 4L80E tranny. It has the factory aux tranny cooler. In relation to the first question in this thread, I'm trying to verify which is the hot line into the rad cooler. It's confusing because I read some posts that say the factory aux cooler is in-line before the rad cooler and some say the other way. Also, I've checked a site that says the front cooler port on the tranny is the cooler feed (after the torque converter) and the rear cooler port is the return line. If this is true, then my rad cooler is before the aux cooler.

Anyway know any different?