6T75 Planetary 2011, used and ready to install. Fits the 6T75. Ships fast from the USA.
A 6T75 that whines with road speed, has lost a gear outright, or came apart full of metal after a 3-5-Reverse waved plate let go usually needs more than clutches. When the pinions are pitted or the carriers are chewed up, the gear train itself has to be replaced. This used GM planetary assembly came out of a 2011 6T75, the heavy-duty version of the six-speed transaxle GM put in its larger front-drive and all-wheel-drive crossovers, and it gives a rebuilder a complete, matched set of gears instead of hunting for individual carriers.
The 6T70 family builds all six forward speeds and reverse from three simple gearsets, which ATRA names the input, reaction and output gearsets. Five clutches and one low one-way clutch hold or drive different members of those sets, and the TCM swaps clutches on every shift with no shift valves in the way. The resulting ratios are 4.48 first, 2.87 second, 1.84 third, 1.41 fourth, 1.00 fifth, 0.74 sixth and 2.88 reverse. Every one of those ratios passes through the pinions and ring gears in this assembly, so a worn bearing or a cracked carrier shows up in more than one range. ATRA lists what makes a 6T75 heavier duty than a 6T70: a shot-peened output carrier, a five-pinion carrier, a wider transfer gear, a stronger differential carrier and a heavier ribbed case. That is why a 6T70 gearset is not a straight swap into a 6T75 that tows.
Gear damage is normally a teardown finding, so start with the cheap checks. Scan for codes, look at what is in the pan, and road test to note which gears are affected. GM bulletin 09-07-30-012F ties no reverse, 3rd or 5th with P0776 to the waved plate, and ATRA warns that the debris from that plate is what damages the reaction carrier. Once the unit is apart, spin each carrier and feel for rough pinions, check pinion end play and look for blued or pitted teeth. Our 6T70 and 6T75 common problems guide walks through the codes and failure patterns, and the Acadia common problems guide covers the crossover bulletins and coverage history.
This set is listed for 2011 6T75 transmissions. ATRA reports that GM updated both the output and reaction carriers for the 2009 model year, deepening the sun gear bearing pockets for thicker, more robust bearings, so a 2011 assembly carries the updated design. Those carriers will go into an earlier case only when the updated bearings go in with them. A 2011 unit also predates the 2013 Gen 2 control update, so it matches other late Gen 1 builds. Check the RPO on your vehicle (ATRA lists MH6 and MY9 for the 6T75), compare pinion count and spline count to your old parts, or send us the year and VIN before you order. The rest of our 6T70 and 6T75 parts are grouped on the model page.
| Fits | 6T75 2011 |
| Part type | Planetary |
| Condition | Used |
| Brand | GM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Possibly, but not as a simple bolt-in. ATRA says the output and reaction carriers changed for 2009 with deeper sun gear bearing pockets. The later carriers back-service only when the matching updated bearings are installed, so plan on new bearings if your case is pre-2009.
It is not recommended. The 6T75 uses a shot-peened output carrier and a five-pinion carrier for its higher torque and tow rating, so a 6T70 gearset gives up that strength.
New waved plates in all clutches, fresh frictions and seals, thrust washers and bearings, and a new filter. If the old gears failed from debris, flush the cooler and lines too.
Check that the input ring gear and its snap ring were installed on the reaction carrier. ATRA notes that parts catalogs show them as one piece but they are serviced separately, and leaving the ring gear out causes no drive with P2723.
Dexron VI only. Check the level at operating temperature after the rebuild and after the first drive.
