4T65E Planetary

A GM front-drive car with a whine that rises and falls with road speed, a gear that suddenly is not there, or shiny metal in the pan often has a worn planetary carrier. This is a remanufactured GM rear planetary, the reaction carrier assembly, rebuilt complete and ready to drop in. The listing covers the 4T65E as well as the older 4T60E, 4T60 and 440-T4 transaxles, which share the rear planet design, so it suits Impala, Grand Prix, LeSabre, Century and Monte Carlo rebuilds as well as earlier Buick, Oldsmobile and Pontiac cars.

What the rear planetary does in a 4T65E

The 4T65E makes its ratios with two planetary gearsets working together, an input set and a reaction set, plus a separate final drive. Each set is a sun gear, a ring gear and a carrier holding pinion gears that turn on needle bearings between thrust washers. The clutches and bands decide which member is held and which is driven, and the rear (reaction) set is in the power flow in every forward gear and reverse. In first, second and reverse the pinions spin hard on their pins. In third, the 1:1 direct gear, the gearsets turn as a locked unit, so a worn carrier is often quiet in third and noisy everywhere else. Sonnax lists the same .750 inch wide pinion thrust washer for 4T65-E output and reaction planetaries that it does for the TH400, which gives an idea of the loads the carrier is built for.

Symptoms of a worn rear planetary

• A whine or growl that follows road speed, worst in first, second or reverse and quieter in third
• Loss of a gear or no reverse while the shift itself still happens
• Bright, fine metal on the pan magnet rather than dark clutch lining
• Clunk or harshness on takeoff from pinions with excess end play
• No movement in any gear if pinion pins or carrier splines let go completely

How to confirm before you buy

Noise diagnosis on a front-drive car needs care, because wheel bearings, CV joints, a failing pump and the final drive can all whine. Note whether the noise changes with gear or only with speed; a final drive or wheel bearing will follow speed in every gear, while a reaction planet usually goes quiet in direct. A pump whine follows engine rpm, which our 4T65E pump failure guide explains. If the pan shows metal, compare input and output speed data before teardown; our speed sensor symptoms guide covers what the sensors report.

Fitment

This listing does not name a year range. It is described as a rear planet for the 440-T4, 4T60, 4T60E and 4T65E, which is the rear carrier these units have in common. GM did revise the 4T65E over its run, so before you install it, set the new carrier beside your original and compare the pinion count and width, the sun and ring gear tooth counts, and the spline on the hub. If they match, it fits. If you would rather we check, send us your year and VIN. Year-specific versions are also listed, including the 4T65E planetary for 1997, and all parts for the unit are on the 4T65E parts page.

Install notes

• Check pinion end play on the new carrier with a feeler gauge and confirm every pinion turns smoothly.
• Replace the thrust bearings and washers on both sides of the carrier, and inspect the sun gear and reaction shell bushings; a worn bushing will wipe out a new carrier. The reaction shell is listed if yours is cracked or the splines are worn.
• Find the source of any metal. Flush the cooler and lines, and fit a new filter and pan gasket kit.
• Fill with DEXRON-VI, which is back-serviceable to the older 4T60E and 440-T4, and check the level with the fluid at operating temperature.

Which transmissions does this planetary fit?

It is listed as a rear planetary for the GM 440-T4, 4T60, 4T60E and 4T65E. Compare pinion count and width, gear tooth counts and the hub spline with your original before installing, or send us your year and VIN.

Is this new or rebuilt?

It is a remanufactured GM unit, rebuilt complete and ready to install.

How can I tell a planetary whine from a wheel bearing noise?

A worn planetary usually changes or goes quiet when the transmission shifts into third, the direct gear. A wheel bearing or final drive noise follows road speed in every gear, and a pump whine follows engine rpm.

What should I replace with the planetary?

Replace the thrust bearings and washers around the carrier, check the sun gear and reaction shell bushings, and fit a new filter. Flush the cooler and lines if the pan had metal in it.

What fluid should I use?

DEXRON-VI. GM specifies it for the 4T65E and made it back-serviceable for transmissions that originally used Dexron III, such as the 4T60E.

• 4T65E Pump Failure Symptoms and Replacement
• 4T65E Input/Output Speed Sensor Symptoms
• 4T65E Common Problems and Diagnosis