Polished finned aluminum pan for GM TH350 and TH250 automatics, stock 2-1/4 inch depth, with gasket, drain plug and socket-head bolts. Part SP8491.
Every fluid change on a factory Turbo 350 ends the same way: loosen thirteen bolts, let one corner sag, and wear the fluid. This polished, finned aluminum pan kit (part SP8491) adds a drain plug to the GM TH350, the lockup TH350C and the TH250/TH250C, which share the same 13-bolt pan. It also replaces a stamped steel pan that has been dented by a jack, dished at the bolt holes from years of overtightening, or seeps no matter how many gaskets you throw at it. It suits the Chevelles, Camaros, Novas, C10s and other 1969-1986 GM cars and trucks that came with a Turbo 350.
The TH350 is a wet-sump unit. The pan is the reservoir the front pump draws from through the filter bolted to the bottom of the valve body, and it is where fluid drains back from the converter and cooler when the engine shuts off. Because the pump pulls straight from it, pan depth matters: a pan that changes the pickup height without a matching filter spacer can let the pump suck air in hard turns or on a hard launch. This kit keeps the factory 2-1/4 in. depth, so the stock filter and pickup work as-is and the pan does not hang any lower under the crossmember than the original.
A TH350 has no computer and sets no trouble codes, so pan and gasket problems show up as wet spots and a low dipstick.
Clean the underside, drive it to full temperature, and inspect with the engine running and again after it sits. The filler tube O-ring, modulator, speedometer gear sleeve and shift shaft seal all drip onto the pan rail and fool people into buying gaskets. Our TH350 fluid leak guide walks through GM's leak-point list in order. If the pan is the culprit, lay a straightedge across the rail of the old pan; dished holes or a wavy rail mean a new gasket will not hold.
This pan is built for the GM TH350 and TH350C and the TH250 and TH250C, all with the 13-bolt TH350 pan pattern. It does not fit the TH400, 700R4/4L60 or Powerglide, which use different pans. If you are not sure what is under your car, count the pan bolts and compare the pan shape with the photos, or send us the year and VIN. Browse the rest of our TH350 parts for internal parts.
Our TH350 filter and pan service guide covers intervals and filter choices. If the old pan showed burnt fluid and friction material, an overhaul kit or a remanufactured pump is the next step, and the fluid capacity guide covers refills after a rebuild.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes. The TH350, TH350C, TH250 and TH250C all use the same 13-bolt pan pattern this pan is made for. It does not fit a TH400, 700R4 or Powerglide.
No. It keeps the stock 2-1/4 in. depth, so the factory filter and pickup height are unchanged and no spacer is needed.
No. The kit includes the pan, gasket, 13 bolts with washers and a drain plug with washer. Install a new TH350 filter (GM 8640848 or equivalent) while the pan is off.
No. The rubber-core gasket installs dry on a clean rail. Sealer can break loose and clog the filter or valve body.
GM lists about 2-1/2 quarts of DEXRON-type ATF after a pan drain on a stock-depth pan. Finish by checking the dipstick hot with the engine running in Park.
