Releases the 1/2 inch spring-clip cooler line fittings on GM 4L60E and 4L80E trucks and vans at the radiator and transmission without removing the clip.
Trying to get a transmission cooler line off a Silverado, Sierra, Tahoe, Suburban or Express van and the fitting will not let go? GM holds those 1/2 inch lines in with a quick-connect fitting and a captured spring clip, and prying at it with a pick usually ends with a bent clip, a scratched fitting or a clip on the shop floor. The OTC 7937 is the dedicated release tool for that fitting on 4L60E and 4L80E trucks and vans. It snaps around the line, slides into the connector and releases it with a quarter turn, one-handed.
Every 4L60E sends hot fluid out of the case, through a steel line to the cooler in the radiator tank or an auxiliary cooler, and back in through a second line. At the case and at the radiator, GM uses push-in quick connects: the tube has a raised bead, and a spring clip inside the fitting snaps behind that bead. To release it, the clip has to be spread evenly from the inside, which is exactly what the slotted body of the 7937 does when you turn it. The clip stays in the fitting, so the line pushes back in and locks without new hardware. The fitting itself threads into the case, and the GM overhaul procedure lists the cooler connector torque at 38 N-m (28 lb ft), so inspect it for damage while the line is off.
A leak at a cooler fitting can drain enough fluid to make a healthy 4L60E slip or flare between gears, and low fluid also runs hot, which is hard on the 3-4 clutch pack. Clean the fittings, check the level hot, and look for wet tubes before buying internal parts. Our 4L60E common problems guide covers which slips point to fluid loss and which point to worn hard parts. If the unit failed and left debris, GM says the converter should be replaced when metal particles are found after flushing the cooler and cooler lines, so do that flush before the new or rebuilt unit goes in.
OTC lists the 7937 for 2WD and 4WD GM pickups and vans with the 4L60E from 1993 on and the 4L80E from 1991 on. That covers the 4L60E in 1993-2013 Silverado 1500, Sierra 1500, Tahoe, Yukon, Suburban, S10, Sonoma and Blazer. It also works on many other GM units that use the same 1/2 inch fitting, as long as there is roughly 1-1/4 inch of straight tube between the fitting and the first bend. It is for the transmission line size, not the larger engine oil cooler line. Not sure your line is the 1/2 inch style? Send us the year and VIN, or browse the 4L60E parts and tools collection.
On the case-side fittings tucked up near the transmission tunnel, you may still need a pick to finish, but the radiator end comes apart in a couple of minutes. If your old lines are too rusted to reuse, the 6AN braided cooler line kit for the 4L60E and 4L65E is a direct way out, and a GM bidirectional scan tool lets you check fluid temperature and codes on the test drive. For the full teardown list, see the bench tools you actually need for a 4L60E rebuild.
| Fits | GM 4L60E (1993-2012) and 4L80E (1991-2013) 2WD/4WD trucks and vans |
| Line size | 1/2 inch transmission cooler line spring-clip fittings |
| Clearance needed | About 1-1/4 inch of straight tube before the first bend |
| Material | Spring steel |
| Model / part number | OTC 7937 |
| Cross reference | CTA A381 GM oil cooler line disconnect tool |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
OTC lists it for 2WD and 4WD GM pickups and vans with the 4L60E from 1993 on and the 4L80E from 1991 on. It also works on other GM units with the same 1/2 inch quick-connect fitting if there is about 1-1/4 inch of straight tube before the first bend.
Normally no. The tool spreads the captured clip from the inside, so the clip stays in the fitting and the line snaps back in. Replace the clip only if it is bent, rusted or missing.
No. It is sized for the 1/2 inch transmission cooler line fitting, not the larger engine oil cooler line.
Clean the tube and fitting first and soak them with penetrant. Make sure the tool is pushed all the way into the connector before turning. Tight case-side fittings sometimes still need a pick to finish.
Some fluid drains from the line and the cooler, so have a pan ready. Top up with Dexron VI afterward and check the level hot with the engine running.
