5L40E Overhaul Kit 1999, new and ready to install. Fits the 5L40E. Ships fast from the USA.
Fluid on the garage floor under a 1999 BMW 323i, 328i, 528i or Z3 automatic, a lazy engagement into Drive on a cold morning, or a 5L40E that only starts slipping once it is fully warm all point to the same thing: rubber and Teflon parts that have hardened and stopped holding pressure. This is a TransTec overhaul kit for 1999-and-up 5L40E and 5L50E transmissions, the gasket and seal package you install during a full teardown. TransTec lists it as part 2439, and it interchanges with the 144002A overhaul kit number used across the industry.
The kit maker describes the contents as gaskets, sealing rings, seals, O-rings and small parts. It is a reseal kit. It does not contain friction plates, steel plates, bonded pistons, bushings or a filter, so an older description that mentioned frictions and steels was wrong and has been corrected here. If teardown shows glazed or burnt clutch material, step up to the 5L40E master rebuild kit, which adds the friction set, and pair either kit with a 5L40E filter and pan gasket kit.
The 5L40E is a GM five-speed built in Strasbourg, France, and every forward ratio comes out of a single Ravigneaux gearset. That design leans hard on hydraulics: each gear change is one clutch releasing while another applies, and the computer times that overlap by controlling pressure. Oil reaches the rotating clutch housings through sealing rings on the pump support and shafts, and it is kept inside the case by the pan, valve body and cover gaskets and a long list of O-rings. Once those rings wear their grooves or the O-rings take a set, apply pressure bleeds away, the overlap stretches and the clutches start to slip and glaze. A full reseal puts every circuit back to a tight fit at the same time.
Check the level correctly first; the 5L40E is a fill-plug transmission, so low fluid is easy to miss and causes many of the same symptoms. Then pull the pan and look at the magnet. Clean fluid with no lining debris and a pressure drop in one range points to a sealing problem this kit addresses. Dark fluid with friction material in the pan means the clutches are also worn. Our transmission pressure testing guide covers reading line pressure by range, and the slipping diagnosis guide helps separate a leak from worn frictions. Shift codes with clean fluid can also come from the valve body side; TransGo traces P0731 to P0735 on this unit to wear in the actuator feed limit valve bore, and a fresh 1999 5L40E solenoid set rules out the electrical side.
This kit is catalogued for 1999-up 5L40E and 5L50E transmissions. For the 1999 model year that means BMW only: the E46 3 Series, the E39 5 Series and the Z3, where BMW calls the unit the A5S 360R. Later GM applications such as the Cadillac CTS, the Solstice, Sky and G8 are covered by the same kit number. One caution from TransGo: 1999-2002 BMW units used different low/reverse and second clutch pistons from later builds, so pistons are not interchangeable across the run even though the gasket set is. Read the ID tag on the left rear of the case before ordering, and if you are unsure, send us the year and VIN. The rest of our parts for this family are on the 5L40E and 5L50E parts page.
| Fits | 5L40E 1999 |
| Part type | Overhaul Kit |
| Condition | New |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
No. It is the gasket and seal set: gaskets, sealing rings, seals, O-rings and small parts. Frictions, steels, bonded pistons, bushings and the filter are not included. If your clutches are worn, choose the master rebuild kit instead.
It is catalogued for 1999-up 5L40E units, which in 1999 went into the E46 3 Series, E39 5 Series and Z3. BMW calls the transmission the A5S 360R. Check the case tag or send us your year and VIN and we will confirm.
Yes, the kit is listed for both the 5L40E and the all-wheel-drive 5L50E version. The internal seal and gasket layout is shared.
Only if the frictions are still in good shape. Pull the pan first. Clean fluid with no lining debris supports a reseal; dark fluid and clutch material on the magnet means the plates need replacing too.
Yes. Clear the old adaptive values with a capable scan tool after the rebuild, then drive through every gear under light and moderate throttle so the computer can relearn clutch fill times.
