Shop 6L80 Parts →
The 6L80 and 6L90 (Silverado, Sierra, Tahoe, Yukon, Escalade, Camaro, and the 6L90 in the 2500-class trucks) run hot. GM's own thermal management keeps the converter clutch slipping at light throttle to warm the fluid fast, and that is fine until you put a trailer behind the truck on a grade in July. Then the pan-temp PID on a scan tool climbs past 240 F, the fluid starts to cook, and the clutch packs lose life every minute you sit there.
A deep aluminum pan does three things: it holds an extra quart or more of fluid, it adds external surface area and cooling fins to shed heat, and the better ones add a magnetic or finned section that pulls clutch material out of suspension. It is not a cure for an undersized cooler, but on a stock or lightly-modified truck it is the single best dollar-per-degree upgrade available.
How Much Fluid Does a 6L80 Actually Hold?
Knowing your baseline matters, because a deep pan only helps if you fill the extra volume. A 6L80 holds roughly 9.5 quarts total at the factory; a 6L90 holds closer to 11.5 quarts. A pan-drop service only moves about half of that. The extra capacity a deep pan adds is listed below, and you must add that fluid or the pan does nothing but look good.
| Pan | Material | Added Capacity | Filter Spacer Needed |
|---|---|---|---|
| PML Deep Pan | Cast aluminum, finned | +2 qt | Yes (included) |
| B&M 70299 | Cast aluminum, finned | +1.5 qt | Yes (included) |
| Mishimoto MMTC | Cast aluminum, finned | +1.5 qt | Yes (included) |
| Dorman 265-841 | Stamped steel, deep | +1 qt | No (stock filter) |
The filter spacer point is the one most people miss. A deep cast pan moves the floor of the sump down an inch or more. If you bolt the stock filter neck back in, the filter pickup is now sitting an inch above the bottom of the pan, defeating most of the added capacity and risking aeration on a hard launch or a steep grade. The good pans ship with a filter extension or a longer-neck filter. Do not run a deep pan with a stock-length filter.
The Pans Worth Comparing
PML Cast Finned Pan — The Shop Choice
PML pours a thick cast pan with deep external fins and a generous internal sump. The casting is heavy enough to act as a real heat sink, the magnet boss holds a strong magnet, and they include the correct filter spacer. This is the pan you see on built tow trucks. It costs more than the rest and it is worth it if you tow regularly or have any power adder.
Check PML 6L80/6L90 deep pans
B&M 70299 Hi-Tek Deep Pan
B&M's finned cast pan is a half-step down in price from the PML with a slightly shallower sump. It includes the filter spacer, a drain plug (the factory pan has none), and a temperature port. For a daily-driver Silverado or Tahoe that sees the occasional trailer, this is the value pick. Torque the pan bolts to spec in a crisscross pattern and re-check after a heat cycle; the gasket settles.
Check B&M 70299
Mishimoto Finned Aluminum Pan
Mishimoto's pan matches the B&M on capacity and adds a built-in temperature sender bung and a clean magnetic drain plug. Fit and finish are excellent and it comes with a real gasket rather than RTV-only instructions. A strong choice if you also want a temp gauge sender location built in.
Check Mishimoto 6L80 pan
Dorman 265-841 — Budget Steel
If the goal is simply a drain plug and one extra quart on a grocery-getter, the Dorman stamped-steel deep pan does that for the least money and uses the stock filter. It will not shed heat like a finned aluminum casting because steel has poor surface area and no fins, so do not buy it expecting a towing temperature cure. Buy it for the drain plug and the easy fluid changes.
Browse Dorman deep pans
Install Notes That Save You a Comeback
- Clearance check before you torque. On 4WD trucks the deepest cast pans sit close to the front driveshaft and crossmember. Mock it up and check clearance at full droop before final torque. PML lists clearance specs per platform.
- Always run the filter spacer if the pan is deep. No exceptions. A starved pickup will burn the trans faster than the heat ever would.
- Fill, then re-check at temp. The 6L80 has no dipstick. Fill cold, run it through the gears, then set level at the GM-specified fluid temp window (around 95 to 113 F) at the check plug. Overfilling aerates; underfilling starves on grades.
- Use the right fluid. The 6L80/6L90 wants DEXRON-VI, full synthetic. A deep pan plus the correct fluid is the combination that actually holds temperature.
- Torque to spec, re-torque after a heat cycle. Aluminum pans and gaskets relax. A second pass after the first drive stops the slow weep that has people blaming the gasket.
Filter, Fluid, and Seal Kit — Ships Same-Day
A deep pan is only as good as the filter and fresh fluid that go with it. gearboxinsider.com stocks 6L80/6L90 filter spacer kits, DEXRON-VI, pan gaskets, and the magnetic drain hardware. Free shipping, same-day ship before 2pm Eastern.
Shop 6L80 Service Parts →FAQ
Will a deep pan really lower my transmission temperature?
A finned aluminum pan typically pulls 10 to 20 F off cruising temps and buys you more thermal mass before the fluid spikes under load. It is not a substitute for an adequate external cooler on a heavy-tow truck; it is a complement. Stacking a deep pan with a proper cooler is the real fix.
Do I need a tune after installing a deep pan?
No. A pan is a mechanical, capacity-and-cooling upgrade. It does not change shift behavior and needs no recalibration.
Steel or aluminum?
Aluminum with external fins if cooling is the goal. Steel only if you just want a drain plug and a little extra fluid on a non-towing truck.