4T40E Planetary, used and ready to install. Fits the 4T40E. Ships fast from the USA.
A 4T40E that howls at highway speed, loses third and fourth, or will not move after the fluid turned black usually has a burnt planet set somewhere in the stack. This is a used GM planet set for the 4T40E and 4T45E four-speed transaxle, sold together with the direct/coast clutch drum, as shown in the photo. It is a hard-parts fix for Chevrolet Cavalier, Malibu, Cobalt and HHR, Pontiac Sunfire, Grand Am, G5 and G6, Oldsmobile Alero and Saturn Ion owners who found melted pinions or a stripped sun gear on teardown.
The 4T40E uses two simple planetary sets stacked behind the drive sprockets. Rebuilder catalogs call the front one the reaction planet, which runs on a 42-tooth sun gear built into the reaction sun shell, and the rear one the input planet, which runs on a 46-tooth input sun gear. Both carriers share the same ring gear design, and the input ring gear is held to the forward clutch hub with a snap ring. By driving or holding different members of these two sets, the forward, direct, coast and reverse clutches, the 2nd clutch and the two bands produce four forward gears and reverse, and the result goes to the final drive sun gear and differential.
The direct/coast drum included here is the housing for two clutch packs that work right on top of this geartrain. The reaction carrier shaft splines into the reaction carrier and carries the direct clutch frictions, so the drum, the shaft and the carriers all move as a system. Several needle thrust bearings sit between them: input planet to forward hub, reaction planet to input sun gear, reaction carrier shaft to sun shell, and input sun shaft to the rear of the reaction carrier shell.
Find out why the planets cooked before you replace them. TransGo ties planet burn-up in this transaxle to wear in the pressure regulator valve bore, the same problem that burns forward and reverse frictions, overheats the fluid and sets TCC codes P0741 and P0742. Check line pressure first with our transmission pressure testing guide. If pressure is low, the pump and valve body need attention along with the geartrain. With the unit apart, spin each pinion, rock it side to side and look for heat color. Measure end play as described in our thrust washer and end play guide.
The catalogs list these planets and the direct/coast drum as one design for 1995-up 4T40E units, and the 4T45E shares the family. That covers 1995-2010 GM front-drive cars such as the Cavalier, Sunfire, Malibu, Alero, Grand Am, Cobalt, HHR, G5, G6 and Ion. The final drive gears are not part of this set and they changed over the years, so this listing has no effect on your axle ratio. Compare the tooth counts and the drum splines with the parts you removed, or send us your year and VIN and we will confirm it. Browse every part for this unit on our 4T40E transmission page.
| Fits | 4T40E |
| Part type | Planetary |
| Condition | Used |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
A used GM planet set sold together with the direct/coast clutch drum, as shown in the photo. Thrust bearings, bushings, seals and clutch plates are not included, and you should replace the bearings during the rebuild.
Yes, the 4T45E shares this planet and drum design. Compare the tooth counts and splines with your old parts before installing, or send us your year and VIN.
No. The final drive sun gear, ring gear and differential are separate parts. This set covers the reaction and input planetary sets plus the direct/coast drum.
Usually from heat and low oil flow. TransGo points to wear in the pressure regulator valve bore as a common cause of burnt planets and frictions in this unit, so check line pressure and the pump before reusing it.
Dexron VI. Flush the cooler and lines first, install a new filter and gasket, and then run an adaptive relearn so the shifts settle in.
