TH350 Master Rebuild Kit 1969-1981, new and ready to install. Fits the TH350. Ships fast from the USA.
Slipping on the 1-2 shift, lost 3rd and Reverse together, or a Turbo 350 that has been sitting in a project car for twenty years with dried-out seals? This is the JEGS 555-62142 high-performance rebuild kit for the 1969-1981 GM TH350, a complete soft-parts and clutch kit meant for doing the whole transmission at once in a Chevy, Pontiac, Olds or Buick car or a light truck. JEGS lists red high-performance clutches, a heavy-duty band, steel clutch plates, all paper gaskets and the pan gasket, rubber O-rings and lip seals, metal clad seals, sealing rings, the filter, front and rear bushings and a modulator in the kit.
The TH350 is a three-speed built around four multi-disc clutch packs (forward, direct, intermediate and low/reverse), one intermediate overrun band and two roller clutches. Line pressure and shift timing come from the vacuum modulator and the governor, not from any solenoid, so nearly every TH350 failure is either a worn friction surface or oil leaking past a seal, ring or worn bore. A complete kit addresses both at once: new frictions and steels in all four packs, a new band for manual 2nd, and fresh rings and seals so each clutch piston gets full apply pressure. The bushings matter as much as the clutches here; worn pump and drum bushings let oil escape from the circuits that feed the clutches, which is how a fresh set of frictions gets burned up again in a few thousand miles.
Before you spend money on a complete kit, rule out the cheap causes. Check the fluid level hot, pull the vacuum line off the modulator and look for ATF inside it, and verify the kickdown and linkage adjustment. A leaking modulator alone can make a healthy TH350 shift late and harsh or soft and early. Our TH350 common problems guide walks through the clutch application chart so you can tell which pack has failed from the symptoms alone. If the pan shows heavy friction debris or the unit has lost a gear outright, a rebuild is the honest answer, and the TH350 rebuild wear points guide lists what to measure once the case is apart.
The listing is titled for 1969-1981 TH350 transmissions, and the maker's feature list also names the TH350C, TH250 and TH250C through 1986. The 1980-up TH350C is the lockup-converter version with an electrical lockup circuit, and some internal parts changed with it, so tell us your year and whether your unit has the lockup wiring connector on the case before you order. Send the vehicle year and VIN, plus any numbers you can read on the transmission identification tag, and we will confirm the kit matches. You can see every Turbo 350 part we carry on the TH350 parts page.
For a cost breakdown of parts versus shop labor before you start, read our TH350 rebuild cost guide.
| Fits | TH350 1969-1981 |
| Part type | Master Rebuild Kit |
| Condition | New |
| 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.
The maker lists the kit for the TH350 and TH350C, but the lockup units changed some internal parts. Send us your year, VIN and whether the case has the lockup wiring connector, and we will confirm fitment before it ships.
JEGS lists red high-performance friction clutches, steel clutch plates, a heavy-duty band, all paper gaskets and the pan gasket, rubber O-rings, lip seals and metal clad seals, sealing rings, a filter, front and rear bushings and a modulator. A shift kit is not included.
A converter that has been running in burnt, contaminated fluid will put that debris right back into the new clutches. Most rebuilders replace or have the converter serviced when the unit failed with heavy friction debris in the pan.
Use a DEXRON-licensed fluid. GM originally specified DEXRON and DEXRON II, and a licensed DEXRON VI is the correct back-service fluid today. Fill a dry unit and converter in stages and finish on the dipstick at operating temperature.
Usually because oil is escaping before it reaches the clutch: worn pump or drum bushings, a cut sealing ring, or a worn bore in the case or valve body. Replace every bushing and ring in the kit and inspect the bores so the new frictions get full apply pressure.
