Saturn Aura
Transmission Problems

The Aura was Saturn's midsize sedan from 2007 through 2009, built on the same Epsilon platform as the Chevy Malibu and Pontiac G6. That matters for two reasons. First, every transmission part for an Aura is a common GM part, so the brand being gone does not make parts hard to get. Second, the Aura shares its failure patterns with millions of Malibus and G6s, so the problems are well understood.

The catch is that GM changed powertrains almost every year, and the Aura ended up with three different automatics: the 4-speed 4T45E, the 6-speed 6T40 and the 6-speed 6T70. They fail in different ways. A shop that diagnoses a 4T45E problem on a 6T70 car, or orders 6T40 parts for a 4T45E, wastes your money.

Which Transmission Is in Your Aura?

The quickest way to confirm is the RPO sticker in the trunk or glovebox: MN5 is the 4T45E, MH7 is the 6T40 and MH2 is the 6T70. If the shifter has a manual "+/-" gate and the dash shows six gears, you have a six-speed. Every version takes Dexron VI.

4T45E Problems (2007-2008 XE, Green Line)

Harsh or flared shifts

The most common 4T45E complaint is a bang into 2nd or a flare on the 1-2 or 2-3 shift where the engine revs up before the gear lands. Most of the time the cause is the pressure control solenoid or wear in the valve body bores, not burned clutches. Old fluid makes it worse. Start with a fluid and filter service with the correct Dexron VI, then check line pressure. If pressure is erratic, a 4T40E/4T45E solenoid kit or a remanufactured 4T45E valve body fixes most of these without pulling the transaxle.

TCC codes and shudder

P0741 and a shudder at light throttle around 40 mph point to the torque converter clutch circuit. On a 4T45E with high mileage, check the TCC solenoid and the fluid condition before you condemn the converter. If the fluid smells burned and the pan has heavy friction material, the converter is likely part of a bigger job.

Slipping in 2nd and 4th

A 4T45E that slips only in 2nd and 4th has a worn 2-4 band or a leaking servo. That is a transaxle-out repair. Our 4T45E problems and cost page walks through confirming it.

6T40 Problems (2009 XE 2.4L)

The 2009 four-cylinder Aura got the then-new 6T40. Early 6T40s share the same weak spot as the bigger 6T70: the 3-5-reverse wave plate. When it breaks, the car loses reverse, 3rd and 5th together while 1st, 2nd, 4th and 6th keep working. If your Aura drives forward but will not back out of the driveway, that is the first suspect. Read the 6T40/6T45 wave plate failure guide before anyone sells you a solenoid.

The other common 6T40 issue is the control solenoid body, which is part of the transmission control module assembly bolted inside the case. It causes harsh shifts, delayed engagement and limp mode. A 6T40 solenoid kit (2009-11) is the parts answer when the fault is electrical and the clutches are healthy.

6T70 Problems (XR 3.6L)

The XR got the same 6T70 used in the Malibu LTZ, G6 GXP and the Lambda crossovers. Its signature failure is also the 3-5-reverse wave plate. Same symptom: no reverse, no 3rd, no 5th. On 2007-2008 cars especially, ask a GM dealer to run the VIN for any prior repair or coverage before you pay for a teardown. The 6T70/6T75 wave plate page covers confirmation.

Beyond the wave plate, 6T70s get shift flares and harsh shifts from valve body wear and adapt values that drifted. A relearn after a proper fluid service clears more of these than people expect. If it does not, a 6T70/6T75 valve body is the next step. For the full picture see GM 6T70/6T75 transmission problems.

Quick Diagnosis Guide

• Six-speed, no reverse, 3rd or 5th: wave plate. Transaxle comes out.
• Four-speed, flares on 1-2 or 2-3, all gears present: pressure control solenoid or valve body.
• Four-speed, slips only in 2nd and 4th: 2-4 band or servo.
• Shudder at steady 35-50 mph: fluid first, then TCC solenoid, then converter.
• Limp mode with clean fluid: check the level, the connector and the solenoids before anything internal.
• Steel flakes on the magnet of a six-speed: the wave plate has already let go.

Fluid and Service

Dexron VI is the only fluid you should put in any Aura transmission. The six-speeds have no dipstick; the level is set at a check plug with the engine running and the fluid in a specific temperature window, so a quick "top off" at a parts store lot is how a lot of them end up overfilled. Change the fluid every 50,000 miles regardless of what the maintenance minder says. For the 4T45E use a 4T40E/4T45E filter and pan gasket kit; for the 2009 2.4L use the 6T40/6T45 filter kit. A gallon of ACDelco Dexron VI covers a drain and fill.

Real Repair Costs

Rebuild or Replace?

Auras are inexpensive now, so be honest about the math. A $500 solenoid job on a clean, rust-free car is easy to justify. A $4,000 six-speed rebuild on a 180,000-mile car with a timing chain rattle is not. On the 3.6L XR especially, listen to the engine on a cold start before spending transmission money.

If you are rebuilding yourself, the 4T40E/4T45E master rebuild kit covers the four-speed and the 6T70 overhaul kit (2007 and up) covers the XR. Confirm you are getting the updated wave plate on any six-speed. Rebuild kits are also available at Core Transmission Parts.

FAQ

What transmission is in a Saturn Aura?

It depends on the year and engine. 2007-2008 XE models with the 3.5L V6 and 2008 2.4L cars use the 4T45E four-speed. The 2009 XE 2.4L uses the 6T40 six-speed. Every XR with the 3.6L V6 uses the 6T70 six-speed. The Green Line hybrid uses a version of the 4T45E.

Why does my Aura have no reverse but still drives forward?

On a six-speed Aura, losing reverse along with 3rd and 5th is the classic sign of a broken 3-5-reverse wave plate. The transaxle has to come out to fix it. On a four-speed, no reverse usually points to the low-reverse clutch or a valve body problem.

What fluid does a Saturn Aura transmission take?

Dexron VI in every version. The six-speeds have no dipstick and are checked at a plug on the case with the engine running at operating temperature.

Are Saturn Aura transmission parts hard to find?

No. The Aura shares its transmissions with the Chevy Malibu, Pontiac G6 and several GM crossovers, so solenoid kits, valve bodies and rebuild kits are standard GM parts.

Is it worth fixing the transmission in a Saturn Aura?

If the engine is healthy and the body is solid, a solenoid or valve body repair is easy to justify. A full rebuild makes sense on a clean, lower-mileage car. On a rough, high-mileage car, a warrantied used unit is the practical choice.