June 22, 2023
OE Part No. 8675519Find a Distributor
GM ’98-earlier 4L80-E transmissions can suffer intermediate backing plate breakage, clutch failure and case lug blow out when pressures are increased for more clutch holding capacity. Sonnax .375" thick, heavy duty intermediate clutch backing plate 34144HD-01 is made of billet steel to withstand higher pressures and features lugs around the entire perimeter to improve durability. This plate can also be used to upgrade the .430" thick plate in TH400 transmissions, allowing for more intermediate clutch setup options.