Here we installed a GM Factory Match transmission temp, boost, and EGT (pyrometer) on a tow truck equipped with the Chevy/GMC Duramax.
We opted to install the gauges into a 5288 universal gauge pod for this application.
Transmission Temperature: This application does not have a readily available pressure port to conveniently thread a sender into. Therefore your choices are to drop the pan, and modify the pan, or you can modify one of the cooler lines. With the high cost of transmission fluid for this transmission, and its recent trans service, we opted to modify the outgoing (from trans to cooler) transmission line.
The case of the trans is identified “TO COOLER” and “FROM COOLER”
We found a straight section of trans line to install our fittings into the outgoing trans line. Use a tubing cutter to cut out a section of line to match the distance needed to install the T with the fittings installed. Keep in mind that the lines need to be long enough to insert into the compression fittings with the T fitting assembled. Straight section shown cleaned and with tubing cutter in place.
These transmission lines are 5/8” in outer diameter. You will want to measure yours to verify size as this is on a heavy duty tow truck. We easily located fittings at a local hardware store that worked perfect for this. We used a ½”NPT 3-way Pipe T, with two 5/8” Compression-to-1/2”NPT fittings.
Below is the installed T fitting set up, with the sender installed into the T, using the supplied ½”NPT to 1/8”NPT bushing (adapter/reducer) that came with the gauge.
Boost Pressure: On this model, as well as earlier models, there is a vacuum (boost reference) line going across the top of the back of the engine for the waste gate. You may use a ¼” Vacuum T to “T” into this line. For later versions, this line is no longer there, which then requires you to remove, drill, and tap into the upper aluminum intake on top of the engine.
In the picture below, you can see the T installed into the waste gate line (viewed from behind the engine in this case).
Tip: Look for the waste gate (seen in the picture) in order to find the line if your truck is either 2002, or 2003 and earlier model years.
Pick up truck & later version without waste gate: Use a 5/16” or Letter R drill bit, then follow through with a 1/8”NPT pipe tap. Use caution when running your tap through the hole. We recommend run it only half way through, then test fit your fittings. The tap has tapered threads that get larger, the deeper the tap goes in.
Upper intake removed, with hole located, drilled, and tapped.
Upper intake reinstalled, with boost line and fitting installed.
EGT (Pyrometer) Installation: In this application, being in the tow truck, the right bank exhaust manifold was accessed from above & behind the engine, through the engine access cover (similar to a van). In your pick up truck, it is easiest to access by removing the right front wheel & tire, and the right front inner wheel house liner. You will drill and tap the exhaust manifold near #8 (last) cylinder. Use a 5/16” or Letter R drill bit, then follow through with a 1/8”NPT pipe tap. Use caution when running your tap through the hole. We recommend run it only half way through, then test fit your fittings. The tap has tapered threads that get larger, the deeper the tap goes in.
Tow truck version shown from above the rear of the engine, from the interior.
Hole Drilled and tapped, and probe fitting installed.
Pick up truck version shown, viewing from right side with tire and inner liner removed.
Pick up truck version shown from further away to give better idea of where you are looking.
Special Thanks to Ron’s Towing of Rochelle, IL for letting us install these gauges into his truck.