15 feet of 6AN braided cooler hose with swivel ends and adapter fittings to replace cracked or rusted GM 4L60E and 4L65E cooler lines.
If your Silverado, Sierra, Tahoe, Suburban, S10, Blazer or Camaro has a wet trail of red fluid running along the frame rail, or a cooler line that has rusted through at a clip, this is the repair. The kit gives you 15 feet of 6AN hose, swivel hose ends and adapter fittings, enough to rebuild both the feed and return lines between a GM 4L60E or 4L65E and the radiator tank or an add-on cooler. Fifteen feet is the useful number here: a full-size truck with the cooler up front and the transmission under the cab eats a lot of hose, and you want enough left over to route around the engine mount and exhaust instead of pulling a line tight.
In a 4L60E the pump feeds the pressure regulator valve, the regulator feeds the torque converter, oil leaving the converter goes out to the cooler, and the oil coming back from the cooler becomes the lube supply for the bushings, gears and clutch packs. Those circuits are connected in series, so a cooler line is not just a radiator plumbing issue. A restricted or kinked line cuts lube flow and lets the converter run hot, and a line that leaks or blows off empties the pan in a matter of miles. GM treats this seriously enough that its own bulletin requires a cooler flush and flow test after transmission work, warning that insufficient cooler flow causes premature failure.
Sonnax published a shop case history on exactly this: on 4L60E trucks where a cooler line popped out at the radiator, the sudden fluid loss burnt the 3-4 clutches in most cases, and a few burnt the forward clutches too. Fix the line before it takes the transmission with it.
Clean the area with brake cleaner, drive the truck to full temperature, and look again with a light. Follow both lines from the case to the cooler, paying attention to the clips, the bends near the oil pan and the crimp ferrules at each end. If the transmission is already slipping, a line repair alone will not bring burnt clutches back; read our 4L60E common problems guide to sort out whether you are dealing with a leak or an internal failure that needs a 3-4 clutch pack or a full rebuild.
The listing covers the GM 4L60E and 4L65E family used in 1993-2013 Chevrolet and GMC rear-wheel-drive trucks, SUVs and cars, including the Silverado and Sierra 1500, Tahoe, Yukon, Suburban, S10, Sonoma, Blazer, Camaro and Corvette. Port threads and radiator connections are not identical across those years: some ends use threaded fittings and others use a snap-in connector at the radiator tank. Check the thread and style at your case and cooler before you cut hose, and if you are unsure, send us your year and VIN and we will help you match it. Browse every part we carry for this unit on our 4L60E collection page.
If the leak ran the truck low long enough to burn clutches, pair this kit with a heavy duty 4L60E rebuild kit with the 3-4 PowerPack so the new lines feed a transmission that will last. Owners of the F-body cars can also see our 4L60E Camaro problems guide for the heat and clutch issues specific to that platform.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
For most 1500-series Silverado, Sierra, Tahoe and Suburban runs from the case to the radiator tank, yes, with some left over. Measure your old lines along the route you plan to use before cutting, and add length for a gentle path around the exhaust.
The kit includes adapter fittings, but GM used different port threads and radiator connections over the years, including snap-in connectors on some radiators. Check your case and cooler ports before you cut hose, or send us your year and VIN and we will help you confirm.
Yes. That is one of the most common uses. Run the auxiliary cooler in series after the radiator tank on the return line, and keep the hose away from the exhaust because its listed limit is 212 F.
Not if the clutches already burned. Low fluid usually takes out the 3-4 clutch pack first. New lines stop the leak, but a slipping 3-4 shift after a fluid loss usually means the transmission needs to come apart.
Dexron VI. Check the level hot, after the truck is fully warmed up, and top off in small amounts because the 4L60E is sensitive to overfilling as well as low level.
