Expands and then resizes the input shaft sealing rings on GM 6L80E and 6L90E transmissions so the input drum slides on without shaving or rolling a ring.
Rebuilding a GM 6L80E or 6L90E from a 2006-up Silverado, Sierra, Tahoe, Escalade, Camaro or CTS means pulling the input drum, and that means dealing with the plastic sealing rings on the input shaft. This two-piece expander and resizer set is for the step where many home rebuilds go wrong: getting new rings onto the shaft without stretching them out of shape, then shrinking them back down so the drum slides over them instead of slicing them.
The six-speed GM units are clutch-to-clutch transmissions, so every shift depends on oil reaching the rotating clutches at the pressure the control module commands. The sealing rings on the input shaft keep that oil inside its own passage as it crosses from the stationary parts into the spinning drum. A ring that is nicked, rolled or left oversized lets oil bleed into the neighboring circuit. The transmission still may move, but the affected clutch applies late and soft and starts to burn. That damage often shows up within a few hundred miles of a rebuild, which is why shops use a sizing tool instead of a screwdriver and patience.
If rings were cut or left oversized on the last rebuild, look for a slipping or flaring shift into one gear range while others are fine, burnt clutch material on the next pan drop, or line pressure that reads low on the scan tool even though the pump is fresh. The 3-5-R and 4-5-6 clutches are already the 6L80's common wear items, so a ring leak on their supply is easy to misdiagnose as a bad clutch pack or a valve body fault. Our 6L80 common problems guide covers how those failures normally present, and the 6L80 pump failure guide explains how to tell a pump or pressure regulator problem from an internal leak.
If you are already tearing down a 6L80E or 6L90E, you need some way to install and size the rings; the overhaul kit supplies new rings but not the tooling. If the transmission is still in the truck and you are only chasing a shift complaint, diagnose first. Check line pressure against command, then use a scan tool to see which gear changes slip. Our 6L80 shift problems guide walks through that process.
This tool is made for the GM 6L80E and 6L90E six-speed used in 2006-up GM full-size trucks and SUVs, the Camaro and the CTS. The 6L90 shares the 6L80's basic layout with heavier internals, and the input shaft ring service is the same job on both. It is not made for the smaller 6L45 and 6L50 or the 8-speed and 10-speed units. Browse the rest of what we carry on the 6L80 parts page.
| Fits | GM 6L80E / 6L90E six-speed (2006-up GM trucks, SUVs, Camaro, CTS) |
| Function | Expands sealing rings onto the input/turbine shaft, then resizes to drum-bore diameter |
| Includes | Expander and resizer sleeve (2-piece set) |
| Material | Tough plastic, non-scoring |
| Dimensions | 6 in L x 2 in W x 4 in H |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes. It is made for the GM 6L80E and 6L90E six-speed input shaft sealing rings. It is not for the 6L45, 6L50 or the 8-speed and 10-speed GM units.
No. The set is the expander and resizer sleeve only. New rings come in a 6L80 overhaul or master rebuild kit.
People try, but plastic sealing rings stretched by hand usually stay oversized and get shaved or rolled when the drum goes on. That leak shows up as a slipping or burnt clutch shortly after the rebuild.
Tough plastic. It flexes the ring without scoring it and will not mark the shaft lands.
Fill with Dexron VI, set the level hot by GM's procedure and reset the transmission adapts with a scan tool, then let the TCM relearn shift pressures on a road test.
