6L45 O-Ring Transmission parts, repair guidelines, problems, manuals

Transmission general data

Number of gears Transmission Type Drive Torque (Nm) ATF (full capacity) L ATF (change) L ATF type
6 AT RWD 450 9,8 6,2 Mercon SP
Related transmission models or modifications of this transmission:
Part type (1) Expand

These gearboxes usually get in repair services for scheduled ATF change, replacement of the filters with the pan gasket. ATF gets contaminated because of aggressive accelerations and wear-out of the lock-up clutch. It is recommended to change ATF in accordance with its contamination level, but no later than after travelling 80 thousand kilometers.


Typical problems

The problem detected on the 6L80 (manufactured before 2008) is related to the design of the pump cover and cranking of filler rings resulting in problems with shifting from the 2-nd to the 3-rd gear and delays in switch-on of Forward or Reverse gears.

In case of the overhaul, it is recommended to check the leak integrity of the drum 555. There may be some hidden cracks leading to the operation pressure losses in packs causing problems when shifting gears 2-3 and Reverse. Overheating is dangerous for all pistons, which have to be fully replaced. It is the problem inherited from its 5-speed predecessor 5L40E.


All pistons and retainers are replaced quite frequently (kit of pistons 6L45-50). Problems with the torque converter (TC) may also occur in these gearboxes. The wheel-hub early gets out of order. Rare and complicated cases of the overhaul show some vulnerability of the pack (4-5-6 Clutch), which in neglected cases leads to burning of all frictions, including steel discs and pistons. The reason is often related to wear-out of the TC bushing and TC itself.


The torque converter is often considered to be a soft spot in American gearboxes. After 100-150 thousand kilometers (depending on engine and driving style), it is recommended to test the TC seal for leaks. When there are leakages in the seal or ATF gets rapidly contaminated, then it is desirable to get TC in repair services to prevent problems with the pump or the valve body. This measure particularly should be applied when automatic gearboxes operate jointly with motors (with maximum torques).