4L85E Overhaul Kit 2005, new and ready to install. Fits the 4L85E. Ships fast from the USA.
A 2005 Chevrolet or GMC heavy-duty truck or van with a tired 4L85E usually tells you in one of three ways: slipping under load, burnt-smelling fluid with debris in the pan, or leaks that keep the fluid level dropping. This 4L85E overhaul kit for 2005 is what you build the transmission back up with once it is on the bench. In 2005 the 4L85E (GM RPO MN8) was the heavy-duty four-speed behind GM's biggest gas and diesel engines, mostly in full-size vans and heavy pickups, so these units tend to fail from heat and load rather than age alone.
Every clutch pack and servo in the 4L85E is applied by oil held in by a seal: piston lip seals, Teflon or cast sealing rings on the shafts and drums, and gaskets between the case, pump and valve body. After high mileage the seals harden and the rings wear, so apply oil leaks away and the clutches slip and burn. This kit replaces that sealing layer in one order. Going by the product photo, it also includes friction plates, steel plates, a band, bushings and a filter along with the gasket and seal set; check the photos against your needs before you order.
An overhaul only fixes what is inside the case, so check the cheaper causes first. Read the codes, test line pressure in each range, and check the solenoids and harness, since electrical faults are common on this family. Sonnax also documents a worn reverse checkball sleeve in the valve body that burns the direct clutch on 1995-and-later units; skip that check and the new plates will burn again. Our 4L85E common problems guide covers the order to test in, and the shift solenoid guide helps rule out electrical faults.
This kit is listed for the 2005 model year. Sonnax groups 4L80E/4L85E parts as '04-later, separate from '97-'03, so a 2005 unit takes the later parts. Match your transmission ID tag, and send us your year and VIN if your vehicle was built close to a model-year change. Other years and versions are on our 4L85E parts page.
| Fits | 4L85E 2005 |
| Part type | Overhaul Kit |
| Condition | New |
| 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.
The 4L80E and 4L85E share the case, valve body layout and most seals, and Sonnax groups them together. Confirm with your ID tag, or send year and VIN and we will check.
The photo shows frictions, steels, a band, bushings, a filter, seals and gaskets. Check the photos against the parts you need before ordering.
Dexron VI, which GM now lists for this family in place of the earlier Dexron III.
Check the pump, valve body and solenoids, and flush the cooler. Many builders also fit a solenoid kit and a new internal wiring harness while the pan is off.
Clear codes and road test gently. GM trucks of this era adapt shift timing over normal driving, so firmness may change over the first few drives.
