TH350 valve body for 1969-1986, remanufactured and ready to install. Ships fast from the USA.
If your TH350-equipped Chevrolet, GMC, Pontiac, Oldsmobile or Buick is shifting harsh, slipping between gears, or flaring on the 1-2 and 2-3 upshift, the valve body is the usual culprit before you start tearing the transmission apart piece by piece. This TransGo unit covers the full 1969-1986 TH350 production run and ships remanufactured with the factory updates already built in, so you are installing a corrected part instead of reinstalling the same worn bores that caused the failure in the first place.
The valve body is the hydraulic brain of the TH350. It routes line pressure through a network of precision bores and spool valves to apply the clutch packs and bands in the right order at the right pressure, which is what makes a shift feel crisp instead of harsh or soft. Every TH350 built across this 1969-1986 window uses the same basic hydraulic layout, so wear in the boost valve, 1-2 accumulator bore, or governor circuit shows up as the same family of complaints no matter which GM car or light truck it is bolted behind.
A worn valve body and a worn clutch pack can look similar from the driver's seat, so it pays to isolate the hydraulic circuit before you order. Our TH350 valve body testing guide walks through pulling the pan, checking the filter for debris, and the vacuum-gauge method techs use to find a leaking bore: a healthy circuit holds roughly 22-23 in. Hg, while a badly worn one can drop as low as 8 in. Hg. If the shifts are specifically harsh rather than slipping, the TH350 harsh shift causes guide covers the line-pressure side of the same complaint.
This valve body is built for the 1969-1986 TH350, used behind Chevrolet, GMC, Pontiac, Oldsmobile and Buick cars and light trucks of that era. The TH350 went through several running changes over its production life, including the shift to the TH350C lockup version in the later years, so match your casting and modulator location against your own unit, or send us your year and vehicle and we will confirm the correct version before you order. Browse the rest of what we stock for this transmission on the TH350 parts page.
Change the fluid and filter at the same time you install this valve body so debris from the old unit does not circulate through the new one and start the same wear pattern over again. Torque the valve body bolts in sequence to spec rather than cranking them down corner to corner, which can warp the body and cause the exact harsh-shift complaint you are trying to fix. The TH350 runs on Dexron ATF; if you are rebuilding more than just the valve body, pair this with our TH350 overhaul kit for new gaskets and filter, or step up to the TH350 master rebuild kit if the clutches and bands are also due.
| Transmission | TH350 |
| Year Range | 1969-1986 |
| Condition | Remanufactured / updated |
| Shipping | Ships from the USA |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is built for the full 1969-1986 TH350 production run behind Chevrolet, GMC, Pontiac, Oldsmobile and Buick vehicles. The TH350 had running changes over that period, so confirm your casting and modulator location match, or send us your year and vehicle and we will verify fitment before you order.
Change the fluid and filter so debris from the old unit does not circulate through the new valve body. If the transmission has higher mileage, pair it with our TH350 overhaul kit or master rebuild kit so the clutches and bands are addressed in the same job.
Harsh, late, or flared shifts, slipping between gears, no engine braking in manual second, and delayed engagement into Drive or Reverse after the vehicle has sat. These come from worn bores inside the valve body losing their seal against the spool valves.
Dexron ATF. Use a fresh fill any time you are into the pan, and make sure the fluid level is correct with the transmission at operating temperature before you judge shift quality.
The TH350 is a fully mechanical-hydraulic transmission with no onboard computer to relearn, so there is no adaptive procedure. Just confirm the linkage and modulator cable or vacuum line are hooked up correctly and road test to confirm shift quality.
This unit is remanufactured by TransGo with the factory updates already incorporated before it ships, so you are getting a corrected part rather than a reconditioned core with the original wear points still present.
