TH400 Valve Body 1964-98, new and ready to install. Fits the TH400. Ships fast from the USA.
If your TH400-equipped GM truck, motorhome, or classic car is shifting harsh, slipping between gears, or not shifting at all, and you've traced the problem to the valve body rather than a clutch or band, this listing covers the full 1964-1998 TH400 production run with a ready-to-install replacement unit.
The TH400 is a fully hydraulic, non-electronic 3-speed on earlier applications, so every shift timing decision lives inside the valve body. It meters line pressure from the pump through a set of precision bores and spool valves, then routes that pressure to apply the direct clutch, forward clutch, intermediate band, or low/reverse band in the correct sequence. A worn bore or a sticking valve shows up immediately as a mistimed or missing shift because there's no computer to compensate.
Pull the pan and check for metal shavings or clutch material before assuming the valve body is the problem - a bad pump or worn clutch pack can mimic a valve body symptom. Our TH400 valve body problems and testing guide walks through isolating a hydraulic valve body fault with line-pressure checks, and the TH400 common problems and fixes guide covers the other wear points - drum, servo, and input shaft - that can produce similar symptoms.
The TH400 ran with multiple internal updates over this 34-year span, including changes to the governor, servo, and later the addition of a lockup torque converter clutch circuit. This listing fits the TH400 broadly across 1964-1998, but match your casting numbers and connector count (if electronically controlled) against your old unit before installing, or send us your year and application and we will confirm the exact match. The full TH400 parts collection has every other part we carry for this transmission if you need to cross-check against sibling valve bodies for your specific year.
Change the fluid and filter at the same time you install this valve body so metal or clutch debris from the old unit doesn't circulate through the new one - a filter and pan gasket set is the cheapest insurance you can add to this job. Torque the valve body bolts in the sequence called out in the service manual rather than corner to corner, since an uneven bolt pattern can warp the separator plate and cause cross-leakage between circuits. The TH400 runs on Dexron ATF; refill to the dipstick mark with the vehicle level and the engine running, then recheck hot. If you're also replacing wear items at the same time, a TH400 overhaul kit covers the gaskets and seals you'll need anyway.
| Fits | TH400 1964-98 |
| Part type | Valve Body |
| 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.
It's built for the TH400 across the 1964-1998 production run, but match your casting numbers and connector count against your old unit, or send your year and application and we'll confirm the exact fit.
Harsh or flared shifts, slipping between gears, delayed engagement, torque converter clutch shudder on electronic units, and shift points that drift with temperature.
Dexron ATF.
Change the fluid and filter at the same time so debris from the old valve body doesn't circulate through the new one, and torque the bolts in the service manual sequence to avoid warping the separator plate.
Pull the pan first and check for metal or clutch material - that points to a mechanical failure instead. Our testing guide covers isolating a hydraulic valve body fault with line-pressure checks.
