4L60E Finned Aluminum Transmission Pan Kit, 265-811

If the stamped steel pan under your Silverado, Sierra, Tahoe, Suburban, Express, Savana, Escalade, S10 or Astro is weeping fluid at the flange or has rusted thin along the bottom, this kit replaces it with a finned cast aluminum deep pan and everything needed to bolt it on in one session: the pan, a pan gasket, a filter, two drain plugs, sixteen mounting bolts and an L-wrench for the plugs. It is built for the 16-bolt deep sump GM used on the 4L60E, 4L65E and 4L70E, and it crosses to 265-811 and to GM pan numbers 24229658, 24240207, 8667545 and 24208576.

What the pan does in a 4L60E

On a 4L60E the pan is more than a cover. It is the reservoir the filter pickup draws from, and its depth sets how much fluid the unit carries. Sonnax notes that GM moved the C/K/G trucks and vans to a deeper pan in 1998 specifically to raise fluid capacity in the heavier vehicles, and paired it with a longer dipstick, tube and dipstick stop bracket. More fluid in the sump means more heat it can soak up before temperature climbs, which is why the 3-4 clutch and converter last longer in trucks that run cool. The fins on this casting add surface area for that heat to leave the pan, and aluminum will not rot through at the bolt rail the way an old steel pan does after years of road salt.

Symptoms that point to the pan

• A fresh fluid spot under the bellhousing-to-tailshaft area that keeps coming back after the pan bolts are snugged
• Rust scale or pinholes along the flange, or a bottom that has been crushed by a rock or a floor jack
• Fluid level dropping between checks, followed by slipping or a late engagement into Drive when the level gets low
• Flaking rust that ends up in the sump every time the pan comes down for service

Low fluid hurts the 4L60E fast. The unit is already known for burning the 3-4 clutch pack under load, and running it a quart or two low on a hot day speeds that up.

How to confirm before you buy

Wipe the bottom of the transmission clean and drive a few miles. Cooler line fittings, the range switch and the rear seal can all drip onto the pan and get blamed for a leak they did not cause, so trace the wet trail back to its highest point. When the old pan is off, study what is in it before you throw it away. A light gray film is normal wear. Strips of friction lining or bright metal mean the leak is not your only problem, and our 4L60E common problems guide explains what each kind of debris usually comes from. Van owners chasing harsh shifts along with a leak should also read the 4L60E Astro Van shift problems guide, since codes like P0748 point at the pressure control solenoid rather than the pan.

Fitment

Listed applications are 1999-2014 Silverado 1500 and Sierra 1500, 2000-2014 Tahoe, Yukon and Yukon XL, 2000-2014 Express and Savana 1500-2500, 1999-2014 Suburban, 2002-2009 TrailBlazer, 1998-2013 Escalade, 2007-2009 Hummer H2, 1998-2004 S10, Sonoma, Astro and Safari, and 1994-2000 C/K 1500-2500. Those year ranges cover several pan and dipstick combinations, so do not order on year and model alone. Count the bolts and compare depth: you need the 16-bolt deep pan pattern. If your truck came with the standard shallow pan, Sonnax warns that mixing a deep pan with the wrong dipstick, tube or stop bracket causes interference or a false level reading, and pre-1998 valve bodies lack the chamfer the later brackets need. When in doubt, send us your year and VIN and we will check it. Other service parts for this unit are on the 4L60E parts page.

Install notes

• Loosen the old pan bolts at one end first so most of the fluid drains to that corner, then remove the rest.
• Pull the old filter straight down; make sure its seal comes out of the case bore with it and is not left behind.
• Scrape every trace of old gasket off the case rail and dry it with brake cleaner.
• Seat the new filter, lay the gasket on the pan, and run the sixteen bolts in snug before tightening them evenly in a crisscross pattern so the flange pulls down flat.
• Install both drain plugs and refill with Dexron VI. A pan drop only exchanges part of the fluid, about 5 quarts on the 2003 Astro per its owner manual, so add it slowly and check the level hot.

If you are doing a full reseal while the pan is down, the 4L60E/4L65E overhaul gasket and seal kit covers the rest of the case. Trucks with late-model shift complaints can add a 2003-on 5-piece master solenoid kit since the valve body solenoids are reachable once the pan is off.

Will this fit my 4L65E or 4L70E?

Yes, it is listed for the 16-bolt deep pan shared by the 4L60E, 4L65E and 4L70E. Confirm your case has the deep pan pattern before ordering.

My truck has the shallow pan. Can I switch to this deep pan?

Only if the dipstick, dipstick tube and stop bracket are changed to the deep pan versions. Mixing them can cause parts interference or an incorrect level reading, and pre-1998 valve bodies do not accept the later bracket.

What comes in the kit?

The finned aluminum pan, a pan gasket, a filter, two drain plugs, sixteen mounting bolts, an L-wrench for the drain plugs and a pair of shop gloves.

What fluid should I use and how much?

Use Dexron VI. A pan drop replaces only part of the total fill, roughly 5 quarts on a 2003 Astro, so add fluid slowly and set the final level hot on the dipstick.

Will a new pan fix my slipping transmission?

Only if the slip came from low fluid caused by the leak. If the old pan holds clutch lining or metal, there is internal wear that needs diagnosis.

Do I need to check fitment with my VIN?

It is the safest way. Send us your year and VIN and we will confirm the pan pattern before it ships.

• 4L60E Common Problems, Symptoms, and What to Actually Do About Them
• 4L60E Astro Van Shift Problems: Diagnosis and Fix
• 4L60E Astro Van Common Problems and Fixes
• 4L60E Chevy S10 Common Problems and Fixes