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The T1 Silverado dropped the transmission dipstick, so this is less an oil-change-style job and more a procedure: drain the pan, pump measured fluid back in through a case fill plug, then set the final level by cracking a check plug while the engine idles and the fluid sits in a narrow temperature window. The wrenching is easy. Getting the level right needs the truck sitting dead level and a way to read transmission fluid temperature, which for most people means a cheap bidirectional scan tool.
The thing people get wrong is fluid choice. A 2019 base 5.3 with the 6L80 takes Dexron VI, a 2.7 turbo or 8-speed 5.3 takes Dexron HP, and the 10L80 behind the 6.2 and 3.0 Duramax takes the much thinner Dexron ULV. Check the RPO code on the glovebox label before you buy anything, and remember one drain and fill only swaps about half the total charge.
| Item | Type | Product search |
|---|---|---|
| Floor jack 2-ton minimum Lifts the truck; the pan must sit level when you set the fluid level. | Required | search retailer |
| Jack stands 3-ton pair, or four for level lifting Supports the truck level at all four corners so the level check is accurate. | Safety | search retailer |
| Wheel chocks Keeps the truck from rolling while it idles in Park during the level set. | Safety | search retailer |
| Safety glasses Hot ATF runs down your arm when the check plug comes out. | Safety | search retailer |
| Nitrile gloves ATF is hot and irritating. | Safety | search retailer |
| Socket set 3/8 in drive, 8-19 mm 6-point; 10 mm and 13 mm do most of the work Pan bolts, skid plate/crossmember bolts and plug bosses. | Required | search retailer |
| Ratchet 3/8 in drive with 3 in and 6 in extensions Access to pan bolts and case plugs around the crossmember and exhaust. | Required | search retailer |
| Hex bit socket set 3/8 in drive, 5 mm-10 mm plus 5/16 in Drain and fill/check plugs on GM 8L and 10L cases are commonly internal hex. | Required | search retailer |
| Torx bit socket set 3/8 in drive, T25-T55 Some plugs and pan fasteners on these units use Torx heads. | Required | search retailer |
| Drain pan 8 qt low-profile Catches the 5-7 quarts that come out of the pan. | Required | search retailer |
| Fluid transfer pump Hand or air-operated with 3/8 in hose, or a 10 mm-thread fill adapter The fill plug is above the fluid level, so fluid has to be pumped in. | Required | search retailer |
| Funnel and clear hose 2-3 ft of 3/8 in clear hose Alternative fill method and lets you see air bubbles and flow. | Recommended | search retailer |
| Scan tool OBD-II tool that reads GM transmission fluid temperature PID The level is only valid in a narrow fluid temperature window; guessing ruins the fill. | Required | search retailer |
| Infrared thermometer Backup sanity check of pan temperature if the scan tool PID is unclear. | Recommended | search retailer |
| Torque wrench 3/8 in drive, 5-80 ft-lb; in-lb wrench useful for pan bolts Pan bolts thread into aluminum and strip easily if overtightened. | Required | search retailer |
| Gasket scraper / plastic pry Cleans the pan flange if you drop the pan for a filter change. | Recommended | search retailer |
| Brake cleaner or ATF-safe cleaner Cleans the pan and sealing surfaces before reassembly. | Consumables | search retailer |
| Shop rags / absorbent pads ATF gets everywhere at the crossmember. | Consumables | search retailer |
| Transmission fluid — Dexron ULV 8L80 and 10L80 (3.0 Duramax, 6.2, most 2020+ 5.3 10-speed); 6-7 qt for drain and fill Correct low-viscosity fluid for the 10-speed and 8L80. | Parts | search retailer |
| Transmission fluid — Dexron HP 8L45 / 8L90 (2.7 turbo, 5.3 8-speed); 5-6 qt for drain and fill Correct fluid for the 8L45/8L90; do not substitute Dexron VI. | Parts | search retailer |
| Transmission fluid — Dexron VI 6L80 (2019-2020 base 5.3 six-speed); 5-6 qt for drain and fill Correct fluid for the 6L80. | Parts | search retailer |
| Drain/check plug seal washers Per GM part number for your unit Aluminum/nylon seal rings are single-use on several of these plugs. | Parts | search retailer |
| Transmission filter and pan gasket kit Only if dropping the pan; unit-specific (6L80 / 8L45 / 8L90 / 10L80) Filter change requires pan removal and a new gasket or reusable molded gasket inspection. | Parts | search retailer |
| Creeper or cardboard You will be under the truck with it idling. | Recommended | search retailer |
2019-2020 base 5.3 trucks often have the 6L80 six-speed (Dexron VI); the 2.7 turbo and many 5.3 trucks use the 8L45/8L90 (Dexron HP); the 6.2 L87, 3.0 Duramax LM2 and most 2020+ 5.3 trucks use the 10L80 ten-speed (Dexron ULV), with some 8L80 applications also on ULV. Plug drive types differ between units — 8L pans commonly use a hex drain plug while 10L80 plugs may be hex or Torx, so check yours before crawling under. Drain-and-fill quantity is roughly 5-6 qt on the 8-speeds and 6-7 qt on the 10L80.
| Transmission pan bolts (8L/10L, aluminum case) | verify in the service manual — commonly around 10 ft-lb (13 Nm) range; do not guess |
| Pan drain plug | verify in the service manual |
| Case fill plug / level control (check) plug | verify in the service manual |
| Transmission crossmember bolts (if removed) | verify in the service manual |
No. All T1 Silverado 1500 transmissions use a sealed fill plug and a level control (check) plug on the case. The level is set with the engine idling and fluid temperature in roughly the 95-115 F window, so a scan tool that reads transmission fluid temperature is effectively required.
About 5-6 quarts on the 8L45/8L90 and 6-7 quarts on the 10L80, versus total fills of roughly 9.5 and 11.5 quarts. Buy at least 8 quarts so you have extra for the level-setting step.
6L80 uses Dexron VI, 8L45 and 8L90 use Dexron HP, and 8L80 and 10L80 use Dexron ULV. Identify the unit by the RPO code on the glovebox or door jamb label — the fluids are not interchangeable.
Sometimes. GM's own fix for the 8L45/8L90 shudder was flushing to Dexron HP fluid, and a couple of drain-and-fills can improve it. If the shudder persists, the torque converter is usually the root cause and needs replacement.