4L85E Pump 2004, remanufactured and ready to install. Fits the 4L85E. Ships fast from the USA.
If your 2004 Chevrolet Silverado or GMC Sierra HD, Suburban 2500 or Express/Savana van with the 4L85E has delayed engagement, slips across several gears at once, or whines in step with engine speed, the front pump is a prime suspect. This is a remanufactured GM pump assembly for 2004 units, and the photo shows it with the pump-to-case gasket.
The 4L85E pump is a vane-type unit bolted to the front of the case and driven by the torque converter hub whenever the engine runs. It is the only source of pressurized fluid in the transmission: every clutch apply, every shift, and converter charge and cooling depend on it. The pump cover also carries the pressure regulator and boost valve, so it is where line pressure is actually set. The 4L85E shares its pump housing design with the 4L80E, but GM revised internal pump hardware during the run, and replacement pumps are grouped 1991-1996, 1997-2003 and 2004-up. This one belongs to the 2004-up group.
Two common faults look like pump failure and are not. A worn boost valve sleeve in the pump bore drives line pressure up toward 500 to 600 psi, with a buzz and very high pressure in Reverse; that is fixed with a valve kit, not a new pump. A worn 3rd/Reverse checkball sleeve in the valve body causes 3rd, 4th and Reverse slip with gear ratio codes. Gear noise is the third trap: GM bulletin PIP3259J covers a planetary whine in 1st and 2nd on 1999-2008 4L80E/4L85E trucks and vans, and for units built after September 1, 2003, which takes in many 2004 trucks, it calls for a rear unit end play check before any repair. Our 4L85E pump failure guide lays out the full test order, and the 4L85E valve body testing guide covers the checkball side.
This pump is listed for 2004 4L85E units. GM changed pump parts between production groups, so compare the casting and the bolt pattern on your old pump, or send us your year and VIN and we will confirm the match. If your transmission is a 1997-2003, the 4L85E pump for 1997-2003 is the correct group. All parts for this unit are in the 4L85E parts collection.
| Fits | 4L85E 2004 |
| Part type | Pump |
| Condition | Remanufactured |
| Brand | GM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
This pump is listed for 2004 units. Replacement pumps for this family are grouped 1991-1996, 1997-2003 and 2004-up. For a 1997-2003 unit, use the 1997-2003 pump, or send us your year and VIN to confirm.
Pump whine follows engine rpm and usually comes with a pressure complaint. Planetary whine is louder in 1st than 2nd, often with no shift problem, and GM bulletin PIP3259J covers it with a rear unit end play check.
Probably not the whole assembly. A worn boost valve sleeve in the pump bore causes very high line pressure, buzzing and high Reverse pressure, and is repaired with a boost valve kit.
A new front seal, the filter and fresh Dexron VI at minimum. If the pan shows friction material, the clutch packs are failing too and a rebuild kit belongs in the job.
Yes. Lubricate the pump gears with fluid before assembly so it picks up pressure fast on the first start, then check the fluid level hot.
