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The 4T40E and 4T45E are GM's transverse four-speed electronic automatics. The 4T40E went behind smaller four-cylinders; the 4T45E is the higher-torque version with a stronger case and wider gears. Internally they share most of their design, which is why most parts are sold as 4T40E/4T45E. You will find them in the Chevy Cavalier, Malibu, Cobalt and HHR, Pontiac Sunfire, Grand Am and G5, Oldsmobile Alero and Saturn Ion, among others.
These are inexpensive units to rebuild, which is exactly why the parts choice matters: the kit is cheap, the labor is not, and buying the wrong valve body or solenoid set for your year is the most common way a DIY rebuild goes sideways.
Overhaul vs Banner vs Master — What Each Kit Actually Contains
Every rebuild kit seller uses the same three tiers, and the names trip people up constantly. Here is what is in the box at each level:
| Kit | What is in it | Buy it when |
|---|---|---|
| Overhaul kit | Gaskets, lip seals, O-rings, piston seals and sealing rings. No friction plates, no steels. | The clutches measured fine and you are resealing a leaker, or you are buying frictions separately. |
| Banner kit | Everything in the overhaul kit plus a full set of friction plates. | The frictions are burnt or worn but the steel plates are flat, unscored and not blued. |
| Master kit | Banner kit plus the steel plates, and usually a filter. Some brands add bushings or bands. | Any unit that slipped hard, overheated, or has unknown history. This is the default for a real rebuild. |
Rule of thumb: if the fluid came out dark and smelled burnt, buy the master kit. Heat warps and glazes steels just as fast as it burns frictions, and putting new frictions against old blued steels is how you end up back on the bench in a few thousand miles.
Our 4T40E / 4T45E Kits
| Kit | Notes |
|---|---|
| 4T40E Master Rebuild Kit | Frictions, steels, gaskets and seals. The right call for a slipping or burnt unit. |
| 4T40E Banner Rebuild Kit | Frictions plus seals and gaskets, for when the steels are reusable. |
| 4T40E Overhaul Kit | Seals and gaskets only, for resealing a leaker or a unit with good clutches. |
| 4T40E/4T45E Filter and Pan Gasket Kit | For the fresh unit, and for routine service afterward. |
Pick the Valve Body by Year and Casting
The 4T40E/4T45E valve body changed during production, and the solenoid layout changed with it. A valve body from the wrong era may bolt on but will not work correctly with your harness and calibration. Match by model year and, when you can read it, the casting number:
| Your unit | Valve body to look at |
|---|---|
| 1997-2001 | 4T40E Valve Body 1997-2001 |
| 2002-2003 | 4T40E Valve Body 2002-2003 |
| 2004-2005 | 4T40E Valve Body 2004-2005 (late design) |
| 2006-2010 | 4T40E Valve Body 2006-2010 |
| 2007-up, casting 24233226 | 4T40E or 4T45E valve body, casting 24233226 |
The same split applies to solenoids. The 4T40E/4T45E control solenoid kit (2004-2010) is for the later units; earlier transmissions use the separate pressure control solenoid (1995-2003) and solenoid kit.
Hard Parts to Check While It Is Apart
- Input drum and sealing rings. Worn ring lands leak apply pressure and cause slips that a new kit will not fix. 4T40E input drum.
- Sprag / roller clutch. A worn or broken sprag shows up as slipping or no-drive in a specific range. 4T40E sprag clutch.
- Reaction shell and planetary. Check splines and pinion end play. Reaction shell and planetary.
- Pump. Scoring here kills line pressure. 4T40E pump.
- Internal wiring harness. Old harnesses crack and cause intermittent solenoid codes. 4T40E internal harness.
Fluid
These units were originally filled with DEXRON III. DEXRON VI is GM's backward-compatible replacement and the usual fill for a rebuilt unit. Flush or replace the cooler lines and cooler after a burnt-clutch failure so debris does not go straight back into the new parts.
4T40E / 4T45E Parts In Stock
Master, banner and overhaul kits, valve bodies split by year and casting, solenoid kits, filter kit, pump and drums. Free shipping on every order.
Shop 4T40E Master Kit → More Rebuild Kits at Core Transmission PartsFAQ
Do 4T40E and 4T45E use the same rebuild kit?
Most soft parts are shared and many kits are sold as 4T40E/4T45E. The 4T45E is the higher-torque version with a stronger case and wider gears, so confirm the listing covers your unit, especially for hard parts and valve bodies.
Which 4T40E valve body do I need?
Match by model year and casting number. The design changed over the production run: 1997-2001, 2002-2003, 2004-2005 and 2006-2010 units use different valve bodies, and 2007-up units commonly use casting 24233226.
What is the difference between a banner kit and a master kit?
A banner kit includes the seals, gaskets and friction plates. A master kit adds the steel plates and usually a filter. Choose the master kit if the unit overheated or the fluid was burnt.
Which solenoid kit fits a 2004-2010 4T40E or 4T45E?
The later units use the control solenoid kit listed for 2004-2010. Earlier 1995-2003 units use the earlier pressure control solenoid and solenoid set.
What fluid goes in a rebuilt 4T40E?
The factory fill was DEXRON III. DEXRON VI is GM's backward-compatible replacement and is the common choice today.