TH350 Overhaul Kit 1969-1986, new and ready to install. Fits the TH350. Ships fast from the USA.
If you are resealing a Turbo 350 that leaks from the front, the tail or the pan, or you are building one on the bench and already have good sealing rings, this TransTec gasket and seal kit covers the rubber, paper and cork side of the job. It is listed for every 1969-1986 TH350, for all makes and models that used it: Chevrolet, GMC, Pontiac, Oldsmobile and Buick cars and light trucks with the three-speed Turbo Hydra-Matic. TransTec is one of the long-established names in transmission soft parts, and this is its standard 350 gasket and seal set.
This kit does not include the Teflon or steel sealing rings on the pump hub and shafts. If your old rings are worn, broken or have cut into their grooves, buy them separately or choose the TH350 overhaul kit that includes sealing rings instead. Frictions, steels, the band, bushings and a filter are also not part of this kit.
Every TH350 circuit is fed by the gear pump at the front of the case and controlled by vacuum modulator and governor pressure rather than a computer. That makes it simple, but it also means there are many places for oil to escape. GM lists the pan, extension housing, filler pipe O-ring, modulator O-ring, detent cable seal, governor cover, speedometer sleeve, manual shaft, pressure tap plug, pump seal and pump bolt washers as factory leak points. The parts in this kit renew most of those joints plus the internal piston seals, so the unit holds pressure inside and stays dry outside.
GM's own service manuals warn that airflow under the car pushes fluid rearward, so the wettest spot is often not the source. Degrease the case, drive it to full temperature, and inspect with the engine running and again after it sits. A red dye check under a black light tells you whether the fluid is ATF or engine oil. The TH350 fluid leak guide covers that procedure point by point. If the transmission also slips or engages late, read TH350 common problems and fixes before ordering, because a burned direct clutch or a worn bore needs more than seals.
The kit is catalogued for the 1969-1986 TH350, covering the non-lockup 350 and the later lockup TH350C. Because pan styles, pump castings and valve body gaskets varied over that run, compare the new gaskets with the ones you remove before discarding anything, and match your case and pan to the parts shown. Opened kits generally cannot be returned. Send us the year, vehicle and VIN if you would like us to confirm fit. Everything we carry for this transmission is on the TH350 parts page.
| Fits | TH350 1969-1986 |
| Part type | Overhaul Kit |
| Condition | New |
| 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.
No. The TransTec kit includes metal-clad seals, rubber seals, lip seals, miscellaneous seals, gaskets and a cork pan gasket, but not the Teflon or steel sealing rings. Inspect yours, and if they are worn buy them separately or use a kit that includes them.
Yes. The external seals and gaskets in the kit let you reseal the pump seal, rear seal, modulator, filler tube and pan. The internal piston seals will simply be left over unless you take the unit apart.
The kit is listed for all 1969-1986 TH350 transmissions, which includes the lockup TH350C. Compare the gaskets to your originals before installing.
No. Pan makers advise against sealer because pieces can break off and clog the filter and valve body. A flat pan rail and even torque are what seal it.
GM specified Dexron ATF. A stock pan takes about 2-1/2 quarts after a drain; a rebuilt unit with an empty converter needs considerably more. Set the final level on the dipstick hot.
