Buick Lacrosse Transmission Problems & Cost | 6T75E / 6T40 / 6T70

The Buick LaCrosse is a mid-size near luxury sedan that GM has been making since 2005. It is one of the most popular premium cars in both North America and China. Over the last three generations, quite a few different Buick LaCrosse transmissions have been used. These include the 4T65E, the 6T45, 6T70, and 6T75E. The latest generation was introduced in 2017, and uses either an 8-speed AF50-8, or a new 9T60 transmission. For the most part, these are fairly reliable gearboxes. However, Buick Lacrosse transmission problems can still occur. So let’s take a closer look at some of the causes and real world cost estimates for some of the most common LaCrosse transmission repairs.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

Buick Lacrosse Transmission Models

Buick Lacrosse: 4T65E Transmission
Buick Lacrosse: 6T40 Transmission
Buick Lacrosse: 6T70 Transmission
Buick Lacrosse: 6T75E Transmission
Buick Lacrosse: AF50-8 Transmission
Buick Lacrosse: 9T60 Transmission

Buick Lacrosse Transmission Replacement Cost Estimate

Pricing varies by model. To be 100% sure on pricing, have your VIN# handy and use our Get An Estimate feature to look up your transmission by VIN#.

Replacement Buick Lacrosse Transmission Cost:

What are the DTC codes related to Buick Lacrosse transmission problems?

Buick Lacrosse Transmission Recalls

2013 Buick LaCrosse Recall – 13V097000

Summary – On certain models of the 2013 Buick LaCrosse, the transmission may inadvertently shift into ‘Sport Mode’, reducing any engine braking effect.
Consequence – As a result of losing engine braking, the vehicle may not slow as expected, increasing the risk of a crash.
Remedy – To fix this problem, GM released a software update for the transmission control module/TCM, and will install it free of charge. Owners can contact Buick at 1-866-694-6546. Or they can call the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236

Buick Lacrosse Technical Service Bulletins (TSB)

TSB 06-07-30-023 – 4T65E transmission 1-2 Shift Shudder

Problem – Shuddering or shaking may be felt during the 1-2 shift, under light acceleration at speeds below 25 mph.
Solution – To correct this common 4T65E transmission problem, the entire second clutch assembly will need to be replaced.

TSB 08-07-30-016 – Slipping, refusal to shift, overheating

Problem – Slipping between the gears, overheating, refusal to shift out of a gear, and/or DTC P0894 or P0218, may be because by friction material debonding from the torque convertor clutch (TCC).
Solution – If the friction material has circulated throughout the transmission, the entire transmission may need to be replaced. It is possible to remove the material from the internal components (like transmission cooler lines and the valve body), but it depends on the extent of the damage.

TSB PI4075 – 6T75 transmission overheating
2010 – 2012 Buick LaCrosse

Problem – The 6T75 transmission could experience an overtemperature situation, even if it’s not warranted by the driving conditions. This issue will be accompanied by a warning message in the drivers information center (if so equipped) and one or both of the following DTC’s: P0218 and/or P0634.
Solution – If a mechanical issue is not determined to be at fault, then it’s possible that the problem is caused by too much transmission fluid, dirty transmission fluid or restrictions in the transmission cooler circuit. Click the above link to learn more about this TSB.

TSB 13120A – Torque converter clutch sticking – 6T70 Transmission | 6T75 Transmission

Problem – The torque converter clutch solenoid can stick due to debris in the transmission. When the vehicle is at the end of a coast-down, as the vehicle is coming to a stop, a stuck solenoid will fail to release the torque converter clutch. This keeps the engine directly connected to the driven wheels. As the vehicle stops, the engine speed will be pulled down below normal idle speed and the engine may stall. The vehicle can be immediately restarted and driven.
Solution – The valve control solenoid should be replaced, and the transmission control module will have to be reprogrammed in order to correct the problem.

PI0376A – Flare or slipping on the shift from 2nd or 6th gear – Buick LaCrosse 6T40

Problem – When this common LaCrosse transmission problem occurs, the driver may experience slipping and/or a sudden flare/surge when the transmission shifts into or out of 2nd/6th gear.
Solution – This problem is often caused by debris blocking the opening on the channel plate and spacer plate that provides oil to the 2-6 clutch regulator valve. To correct the issue, the channel plate, spacer plate and valve body will have to be cleaned.

Common Problems with the Buick Lacrosse Transmission

Axle seal leak – Buick LaCrosse 6T40E

Problem – A transmission fluid leak on the driver side, is often traced back to the driver side axle seal.
Solution – This issue stems from a failure prone drivers side axle bushing, which often fails to poor material quality and lubrication. An upgraded bearing will have to be installed.

TCC Solenoid Circuit DTC – 2006-2007 Buick LaCrosse 4T65E

Problem – Diagnostic trouble codes (P0742, P2761, P2764) relating to the torque convertor clutch, may be caused by an incorrectly routed internal wiring harness that can short itself out over time.
Solution – To solve this problem, reposition the tan colored TCC solenoid so that it does not come in contact with the metal wiring harness retaining clip.

Lack of Response
Leaking Fluid
Low Fluid
Burning Smell
Grinding or Shaking
Whining, Clunking or Humming
Refuses to Go Into Gear
Torque Converter Issues
Valve Body Issues
Transmission Noisy in Neutral
Gears Slipping
No 3rd or 4th Gear
No 1st or 2nd Gear
No Reverse
Dragging Clutch
Trouble Codes / Check Engine Light

Can I drive with a transmission problem?

Many people assume that because there are still able to drive their car, a transmission repair can wait. But that’s hardly the case. Most Buick LaCrosse transmission problems start out small, but wind up being extremely expensive because other components wound up breaking or wearing out while the car was still being driven.

How often does a Buick Lacrosse transmission need to be replaced?

Proper maintenance can extend the life of almost any transmission. However, inherent design flaws can cut the service life considerably. The average lifespan of a Buick LaCrosse transmission tends to be between 130,000-180,000 miles. A high quality replacement transmission on the other hand, can sometimes last a lot longer.

How are Buick Lacrosse transmission issues diagnosed?

In order to properly determine what is causing your 6T40 transmission problems / 6T70 transmission problems / 6T75 transmission problems, a mechanic will need to connect a code reader to the OBDII port and pull the diagnostic trouble codes. They will then need to perform a visual inspection to determine the cause of the problem.

How is a Buick Lacrosse transmission replaced?

Since the Buick LaCrosse is primarily a front wheel drive vehicle, the engine will have to be unbolted in order to remove the transmission. Installation is simply a reverse of the removal process. However, the PCM/ECU will have to be reprogrammed / reflashed to accept the new transmission using the latest GM subscription.

Recommendations for Buick Lacrosse transmission issues?

To save time and get back on the road faster, have your 17-digit truck VIN# handy and you can get an online quote for a reman Buick Lacrosse transmission here, then find a local shop using our Find a Shop guide to install it for you.

How to Solve Buick Lacrosse Transmission Problems

Solution A: Buy a Used Buick Lacrosse Transmission
The quickest way to fix your transmission problems is to simply buy a used transmission or used transmission. These can be found at most junk yards, and they often come with a 30-90 day warranty. However, there’s no way to determine the actual condition of the internal components, so you could be spending a bunch of money to have the exact same problems. Plus, that warranty only covers the transmission if it’s defective, not the labor costs that you’ll have to pay.
Solution B: Buy a Rebuilt Buick Lacrosse Transmission
Another option would be a rebuilt transmission or rebuilt transmission. A local repair shop will remove your transmission, then install a bunch of new parts during the rebuild. The problem here is, the skills and experience of each transmission rebuilder will vary widely from shop to shop, so you could have problems from something that wasn’t adjusted properly. And the 1-2 year warranty might only cover you at certain transmission repair shops, in a specific geographical area.
Solution C: Buy a Remanufactured Buick Lacrosse Transmission
Many owners depend on their vehicle to commute and get things done. Their gasoline engines are designed to go 100’s of thousands of miles, so it makes sense to invest in a remanufactured transmission.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

What Problem Does Your Buick Lacrosse Have?

Let us know the year, mileage and problem you’re having as well as any trouble (OBD) codes you’ve found. If you’ve been given a quote or paid for a repair, we’d like to hear about that too!