TH350 Pump 1969-1979, remanufactured and ready to install. Fits the TH350. Ships fast from the USA.
If your Turbo 350 is slow to grab Drive and Reverse once it gets warm, slips in every range at the same time, or whines with engine speed while the car is parked, the front pump is the first suspect. This is a remanufactured pump for the 1969-1979 non-lockup TH350 used behind small blocks and inline sixes in Chevelles, Novas, Camaros, Firebirds, Cutlasses and Chevy and GMC half-ton trucks. It was fully torn down, cleaned, inspected and machined, then built back up with new gears, new bushings, a new front seal, a new outside O-ring, a new gasket and all new screws, so it goes in as a complete assembly rather than a reseal of your worn one.
The TH350 uses a gear-type pump: an inner drive gear and an outer driven gear separated by a crescent, running in a pocket machined into the pump body. Two tangs on the drive gear lock into the converter hub, so the pump turns whenever the engine runs. Everything else in the transmission depends on that oil. The pump cover also carries the stator shaft, the intermediate clutch piston and the hub that feeds the forward and direct clutches through sealing rings. That is why a tired TH350 pump does not hurt one gear. It drags down line pressure everywhere, and it gets worse as the fluid thins out with heat.
The TH350 has no computer and sets no trouble codes, so diagnosis is done with a gauge and your eyes.
Set the fluid level first and look at the dipstick. Bubbles point to an air leak on the suction side, and milky fluid means water; either one lowers pressure with a good pump. Check the modulator and vacuum line, then put a gauge on the line pressure tap. Pressure that is low in every range, and drops further as the fluid warms, is the worn-pump pattern. Pressure low only in Reverse points more toward the pump hub sealing rings and the direct clutch circuit. Our TH350 pump failure symptoms guide lays out GM's pressure specs and the full test sequence, and the delayed engagement guide covers the cheaper causes, like a plugged filter, to rule out first.
This pump is for the 1969-1979 non-lockup TH350. It is not for the TH350C lockup version that GM phased in from late 1979, which needs a lockup-style pump. Within the non-lockup years, pumps were built with either a thrust bearing or a thrust washer at the front of the direct clutch drum. Look at the one you remove and tell us which style you need when you order, or send your year and VIN and we will match it. All of our Turbo 350 parts are on the TH350 collection page.
If the pump came out because the unit is tired overall, do the job once: an overhaul kit covers the seals and gaskets throughout, and a remanufactured input drum is worth having on hand if the forward drum shows scoring or cracked feed holes.
| Fits | TH350 1969-1979 |
| Part type | Pump |
| Condition | Remanufactured |
| 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. This is a non-lockup pump for 1969-1979 TH350 units. The TH350C lockup transmission phased in from late 1979 needs a lockup-style pump. If you are not sure which one you have, send us the year and VIN or a photo of the pump you removed before ordering.
Non-lockup TH350 pumps were built with either a thrust bearing or a thrust washer at the front of the direct clutch drum. Match the style that came out of your transmission and note it with your order so the correct version ships.
No. The pump bolts into the front of the case behind the converter, so the transmission has to come out of the vehicle and the converter has to come off. Most people do the pump during a rebuild or when the unit is already on the bench.
Use a current licensed DEXRON VI ATF, which is back-compatible with the DEXRON II the TH350 originally used. With a stock pan and an empty converter plan on roughly eight quarts plus what the cooler holds, and finish the fill by the dipstick at operating temperature.
Maybe. Low pressure only in Reverse often points to broken pump hub sealing rings feeding the direct clutch, or a direct or low-reverse piston seal leak. A line pressure test in each range tells you whether the pump body itself is weak or just the Reverse circuit.
