6T40 Sprag Clutch, new and ready to install. Fits the 6T40. Ships fast from the USA.
This is a new ACDelco low one-way clutch, part number 24274198, for the GM 6T40 six-speed transaxle. Most people call it the 6T40 sprag. If your Cruze, Malibu, Equinox, Terrain, Sonic, Regal, Verano or Encore pulls away with a slip, a delay or no first gear at all, while second and up feel normal, this part is one of the first suspects. It comes new in OE packaging with a 1-year warranty, so you are not gambling on a used core with unknown miles.
The 6T40 is a clutch-to-clutch transmission with one exception, and this is it. In Drive first gear, the solenoid and clutch apply chart in Sonnax's 6T40 Gen 2 guide shows only two things working: the 1-2-3-4 clutch applies and the low one-way clutch holds. There is no band and no second friction holding first. The one-way clutch carries the whole reaction load every time you leave a stop.
On the 1-2 upshift the TCM applies the 2-6 clutch and the one-way clutch simply overruns. Nothing has to be released or timed, so that is the one shift on this unit that does not depend on adapt values. In manual low the Low and Reverse clutch also applies to give engine braking. The chart lists the one-way clutch as "holding but ineffective" there because the clutch pack has taken over. In Reverse the 3-5-R and Low and Reverse clutches carry the load, not the one-way clutch.
That manual-low test is the key one. If the car will not pull in Drive first but does pull in L1, the Low and Reverse clutch is doing the job the one-way clutch should be doing. That points hard at this part.
Rule out the easy stuff first. Check the fluid level hot at the level set plug, read codes, and watch input and output speed on a scan tool during a first-gear launch. A 1-2-3-4 clutch problem, like the cracked bonded piston GM techs see on these units, can also make first slip. The difference is that it usually slips in second, third and fourth too. Our 6T40 delayed engagement guide walks through which clutch applies for each engagement. The 6T40 gear ratios and specs guide has the full apply chart if you want to work through slip by gear.
This listing is the ACDelco 24274198 low one-way clutch for the 6T40. The 6T40 and 6T45 family ran in 2008-2019 Chevrolet Cruze, Malibu, Equinox and Sonic, Buick Regal, Verano and Encore, and GMC Terrain. GM changed the unit in 2012 (Gen 2), and GEARS Magazine reports a Gen 3 update that gave the diode one-way clutch an aluminum pocket plate. Transmission Digest lists 24274198 as the Gen 2 diode and 24274199 as the redesigned Gen 3 diode, so this part is the Gen 2 piece. Compare the number and the inner race on your old part, or send us your year and VIN before ordering. If yours is from a 2013 Malibu 2.5L, also look at our used 2013 6T40 one-way clutch. For the heavier-duty unit there is a 6T45 version too.
| Fits | 6T40 |
| Part type | Sprag Clutch |
| Condition | New |
| Brand | ACDelco |
| Reference | 24274198 |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
In Drive it can. First gear in Drive is held only by the 1-2-3-4 clutch and the low one-way clutch, so if the one-way clutch freewheels both ways you get a neutral feel from a stop. Manual low usually still pulls because the Low and Reverse clutch applies there.
No. Reverse on the 6T40 uses the 3-5-R clutch and the Low and Reverse clutch. If reverse is also bad, look at those clutches, the 3-5-R wave plate and the solenoids before blaming the one-way clutch.
The 6T40 and 6T45 share the layout, but the diode changed with Gen 3. Transmission Digest lists 24274198 for Gen 2 and 24274199 for Gen 3. Match 24274198 to the part you removed or send your year and VIN and we will check it.
Replace any burnt Low and Reverse frictions, the seals you disturb, and inspect the pocket plate and race. Most people doing this job put in a master rebuild kit at the same time since the unit is already apart.
DEXRON-VI, with the level set hot at the check plug. Clear the shift adapts and run the fast learn procedure after the repair so the TCM relearns clutch fill times.
