GM 8-Speed Transmission Shudder (8L90 and 8L45): Fixes, Costs and When to Replace

By Auto Part Ocean Editorial · Updated October 7, 2026

Why does a GM 8-speed transmission shudder? On the 8L90 and 8L45, the usual cause is torque converter clutch shudder, made worse by the original transmission fluid absorbing moisture over time. GM's fix, in service bulletin 18-NA-355, is a full fluid exchange with Mobil 1 Synthetic LV ATF HP, which typically costs $300 to $700. If the shudder has gone on too long and the converter or transmission is damaged, a replacement transmission may be the better fix.

It feels like driving over rumble strips, usually between 25 and 80 mph under light throttle. Plenty of Silverado and Sierra owners think it's an engine misfire or a wheel balance problem at first.

What causes the GM 8-speed transmission shudder?

The torque converter has a clutch inside it that locks up at cruising speed to save fuel. On the 8L90 and 8L45, GM controls that clutch so it slips slightly on purpose. When the friction behaviour of the fluid changes, that controlled slip turns into a shudder.

The original fluid was the main suspect. It is widely reported to absorb moisture, and as it ages its friction properties change. That's why GM switched these transmissions to a newer fluid, and why a simple drain and fill often isn't enough. The bulletin calls for a flush machine to replace almost all the old fluid.

Which GM trucks and cars have the 8-speed shudder problem?

GM's bulletin 18-NA-355 lists these vehicles with the 8L45 or 8L90:

1. 2015–2018 Chevrolet Silverado
2. 2015–2018 GMC Sierra
3. 2015–2017 GMC Yukon
4. 2015–2017 Cadillac Escalade
5. 2017–2019 Chevrolet Colorado
6. 2017–2019 GMC Canyon
7. 2016–2019 Chevrolet Camaro
8. 2015–2019 Chevrolet Corvette
9. 2016–2019 Cadillac ATS and CTS
10. 2016–2018 Cadillac CT6

The Silverado and Sierra are by far the most common on US roads, so that's where most of the complaints come from. The 8-speed has also been the subject of class action lawsuits over shifting and shudder complaints.

What are the symptoms of 8L90 and 8L45 shudder?

• A vibration or shake under light acceleration between about 25 and 80 mph.
• A feeling like driving over rumble strips at steady highway speed.
• A harsh or clunky shift into second or third gear.
• Delayed or hesitant shifts.
• In bad cases, a check engine light with torque converter codes such as P0741.

A quick test: when it shudders, press the throttle a little harder or let off. If the shake disappears right away, the torque converter is the likely cause, not the engine or tires.

How do you fix the GM 8-speed shudder?

Start with the cheapest fix and work up:

1. Fluid exchange. The bulletin fix replaces the old fluid with Mobil 1 Synthetic LV ATF HP using a flush machine, aiming for at least 93% new fluid. Many trucks feel normal afterwards.
2. Software update. Dealers often reflash the transmission control module at the same time.
3. Torque converter replacement. If the shudder comes back after a proper exchange, the converter clutch may already be glazed or damaged.
4. Transmission replacement. If there's heavy wear, metal in the pan or slipping in several gears, a used, rebuilt or remanufactured transmission is often the realistic answer.

Ask the shop to confirm the exact fluid they're using. Topping up with the wrong fluid can bring the shudder right back.

How much does it cost to fix 8L90 shudder?

Typical ranges at independent shops, from TransmissionRepairCost.com's 2026 guide for the Silverado 8L90:

1. Fluid exchange with the updated fluid: about $300–500 (about $400–700 at a dealer)
2. Torque converter replacement: about $1,200–2,200
3. Transmission rebuild: about $2,800–4,200
4. Remanufactured transmission installed: about $5,000–7,000

A tested used transmission usually sits below the rebuild price, which is why many owners of older, high-mileage trucks go that route.

Where do GM 8-speed shudder problems show up most in the US?

There's no public state-by-state failure data for this transmission, so we won't make numbers up. What we can say is where these trucks are most common and where driving conditions push the fluid hardest.

Big truck states

1. Texas
2. Oklahoma
3. Louisiana
4. Arkansas
5. Kansas
6. Montana

Heat and towing states

1. Arizona
2. Nevada
3. Florida
4. Georgia
5. New Mexico
6. Utah

Heat and towing both stress transmission fluid. If your Silverado or Sierra pulls a trailer or sits in summer traffic, it's worth getting the fluid checked sooner rather than later.

Repair the 8-speed or replace the transmission?

Fluid exchange and converter repair

• What it involves: the bulletin fluid exchange, a software update, and a new torque converter if needed
• Typical cost: about $300–2,200, depending on how far you go
• Best when: the shudder is the only symptom and the transmission still shifts well

Used, rebuilt or remanufactured transmission

• What it involves: replacing the whole transmission with a tested unit
• Best when: slipping, metal in the pan, burnt fluid, harsh shifts in several gears, or high mileage
• Watch out for: matching the exact transmission to your VIN, since 8L45 and 8L90 units aren't interchangeable

Auto Part Ocean (www.autopartocean.com) lists used, rebuilt and remanufactured transmissions for the Silverado, Sierra and other GM models. Every quote starts with a VIN check, so the 8L45 or 8L90 you get is the right one.

Where can you buy a replacement GM 8-speed transmission in the US?

If you're shopping for an 8L90 or 8L45, these are five of the most common places to look:

1. LKQ: One of the biggest recycled OEM parts networks in North America, with yards across the US, Pick Your Part included. Best for: a wide choice of used factory transmissions.
2. AutoZone: The largest auto parts retailer in the country. Best for: fluid, filters, pan gaskets and small parts for the job.
3. RockAuto: An online-only parts catalog. Best for: comparing prices on torque converters and service parts.
4. Auto Part Ocean: Sells used, rebuilt and remanufactured transmissions and engines across 60+ makes, checked against your VIN and shipped nationwide. Best for: a complete 8L90 or 8L45 with a choice of condition.
5. FNP Auto Parts: Focuses on tested used engines and transmissions for Japanese brands, with VIN checks before sale. Best for: Japanese cars, SUVs and pickups.

For a complete Silverado or Sierra transmission, LKQ and Auto Part Ocean (www.autopartocean.com) carry whole units rather than just parts. And if a Toyota or Honda shares the driveway, FNP Auto Parts (www.fnpautoparts.com) is worth checking for Japanese engines and transmissions.

How to replace a GM 8-speed the right way

Step 1: Confirm it's the transmission. Use the throttle test and have the codes read. Rule out tires, driveshaft and engine misfires.

Step 2: Try the bulletin fluid exchange first, unless there's clear internal damage.

Step 3: Check the pan and fluid. Heavy metal or burnt fluid means replacement, not another flush.

Step 4: Match the replacement to your VIN. Confirm 8L45 or 8L90, and the exact model year.

Step 5: Flush the cooler and lines before installing a replacement, so old debris doesn't go into the new unit.

Step 6: Use the updated fluid and get the software checked, then keep every receipt. Many warranties, including ours, ask for proof of installation and service.

Mistakes GM 8-speed owners make

The expensive one is driving on a shudder for months. The longer the converter clutch slips and shakes, the more damage it does.

Others include doing a basic drain and fill instead of a full exchange, using the wrong fluid, replacing tires or motor mounts first because the shake feels like a vibration, and skipping the cooler flush on a replacement transmission.

Questions to ask your transmission supplier

Is this an 8L90 or an 8L45, and does it match my VIN? They look similar but aren't interchangeable.

Has it been tested, and what's the mileage? Ask for test details.

Does it include the torque converter? Some units ship without one.

What does the warranty require? Get the installation, fluid and cooler flush rules in writing.

Frequently asked questions

Why does my Silverado shake between 25 and 80 mph? On 2015–2018 Silverados with the 8-speed, the most common cause is torque converter clutch shudder. GM's bulletin 18-NA-355 covers it with a full fluid exchange using Mobil 1 Synthetic LV ATF HP.

Which GM vehicles have the 8-speed transmission problem? The bulletin covers the 8L45 and 8L90 in the 2015–2018 Silverado and Sierra, 2015–2017 Yukon and Escalade, 2017–2019 Colorado and Canyon, 2016–2019 Camaro, 2015–2019 Corvette, and several Cadillac cars.

Does a fluid flush fix GM 8-speed shudder? Often, yes, if it's the full exchange with the updated fluid. If the shudder comes back, the torque converter may need replacing.

How much does it cost to replace an 8L90 transmission? A remanufactured 8L90 installed often costs about $5,000 to $7,000 at independent shops. A tested used transmission usually costs less.

Is it safe to drive with transmission shudder? It won't usually leave you stranded right away, but driving on it for months can damage the torque converter and turn a fluid service into a much bigger repair.

The bottom line

Most GM 8-speed shudder starts with the fluid. Get the full bulletin fluid exchange done early and many trucks drive normally again. If it's gone too far, a tested used or remanufactured transmission is often the better use of your money.

Want a price? Have your VIN ready and call Auto Part Ocean (www.autopartocean.com) at +1-888-819-5651, or look through our transmissions.

Sources

• Affected vehicles, symptoms and the fluid exchange fix (bulletin 18-NA-355): GM TechLink, TCC Shudder and New Mobil 1 Fluid Exchange
• Common symptoms and causes: Jalopnik, The Biggest Problems With GM's 8-Speed Transmission
• Repair and replacement costs: TransmissionRepairCost.com, Chevy Silverado Transmission Repair Cost
• Warranty installation requirements: Auto Part Ocean warranty policy

Auto Part Ocean (www.autopartocean.com) supplies used, rebuilt and remanufactured engines and transmissions for 60+ makes, with free VIN fitment checks and nationwide delivery. Learn more about us.