Billet aluminum accumulator plate that replaces the stamped GM 4L80E plate to firm up the 2-3 and 3-4 shifts and hold clutch apply pressure.
Owners who tow with a 4L80E-equipped Silverado, Sierra or Suburban, or who have dropped one behind an LS swap, often say the same thing: the upshifts into third and fourth feel long and lazy. That slow, cushioned feel is designed in. This billet aluminum accumulator plate kit, with its cover and mounting bolts, is a shift-firming part for GM 4L80E and 4L85E transmissions (RPO MT1 and MN8) from 1991 on. It is a modification for people who want a crisper 2-3 and 3-4 upshift, not a stock replacement part.
An accumulator is a spring-loaded piston teed into a clutch apply circuit. When the computer commands a shift, some of the apply oil strokes the accumulator piston instead of going straight to the clutch, which stretches the clutch apply over a short window so the shift feels smooth. On the 4L80E, GM's service procedure removes the third and fourth clutch accumulators as one bolted housing on the valve body. That cushion is pleasant in an empty truck, but under a heavy load or with more power, a long apply means the clutch spends more time slipping before it locks, and that slip is heat. Builders have long used a plate in place of that factory hardware to take the accumulator cushion out of those circuits, then controlled shift feel with the feed orifice size instead.
It will not cure slipping caused by worn clutches, low line pressure or electrical faults. Forward and direct clutch wear under heavy towing is one of the most common 4L80E failures, and no plate will bring burnt frictions back.
First make sure the transmission is healthy. Scan for codes, check fluid level and condition, and put a gauge on line pressure while watching commanded EPC current. A weak pressure control solenoid or a worn accumulator control valve bore will also produce soft shifts, and those need repair, not a delete. Our EPC solenoid symptoms guide covers the electrical side, and Silverado 2500 shift problems walks through the common shift complaints on the pickup.
Listed for GM 4L80E and 4L85E (MT1 and MN8), 1991 and up, the full heavy-duty run in Chevrolet and GMC 2500 and 3500 pickups, Suburban 2500, Express and Savana vans and the Hummer H1, plus aftermarket swaps. Manufacturer part number MQ-A71W1300. Before installation, lay the plate on your existing accumulator housing and confirm the bolt holes and passages line up, since GM made running changes to the valve body over the years. If in doubt, send us your year and VIN or a photo of your housing. Other 4L80E parts are on the 4L80E parts page.
Drain the fluid and drop the pan and filter. The accumulator housing is on the valve body; GM's procedure removes its six bolts, starting from one end, and takes the housing and springs out as an assembly. Clean the mating surface, fit the plate and cover with the supplied bolts, start them finger tight and work across the part, then torque to the factory 97 inch-pounds. The size of the feed hole changes how firm the shift feels, so follow the kit's directions and do not enlarge it by guesswork. Refill with Dexron VI. Since the pan is off anyway, fit a new 4L80E filter and gasket kit, and if the shift solenoids are original, the A and B shift solenoid kit is an easy add.
| Material | Billet aluminum |
| Fitment | GM 4L80E / 4L85E (MT1 / MN8), 1991-up |
| Includes | Accumulator plate, cover, mounting bolts |
| Manufacturer Part Number | MQ-A71W1300 |
| Weight | 6.4 oz |
| Package Size | 6.38 x 3.07 x 1.26 in |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes, that is its purpose. Removing the third and fourth accumulator cushion shortens the 2-3 and 3-4 apply so the shifts are firmer and quicker. If you want stock shift feel, leave the factory housing in place.
Yes. It is listed for both the 4L80E (MT1) and 4L85E (MN8), 1991 and up. Check that the plate lines up with your accumulator housing bolt pattern before you install it.
No. The accumulator housing bolts to the valve body, so it can be reached with the pan and filter removed. It is often done during a rebuild or shift kit job.
Only if the slip is the long, cushioned apply built into the stock design. If the direct clutch is worn, line pressure is low or the EPC solenoid is weak, fix that first.
The factory accumulator housing bolts are torqued to 97 inch-pounds (11 Nm), tightened in sequence from one end to the other. Use that unless the kit instructions say otherwise.
The 4L80E does not need a scan tool relearn for this part. Clear any codes, refill with Dexron VI and road test through every shift.
