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Originally Posted by cherryelky305
I would go out and look but its at the shop now getting brakes done. I think its the 350. Which tranny should i look for since i want a 4 speed? I thought that the TH400 was a 4 speed.
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The TH350 has a square pan with one corner cut off, the TH400 has a sort-of-kidney-shape to its pan. They're both 3-speeds. The 400 can handle more power, but the 350 has better gearing, shift points and wastes less HP (less rotating mass). Yours is likely to be a TH350, since those about went into everything except heavy-duty trucks (i.e.3/4 ton) in 1980.
If you want a 4-speed with OD, you have two choices - the TH2004R and the TH700R4 (4L60 in later years). The TH2004R has gearing that's more or less in line with other transmissions, while the TH700R4 has a short 1st gear that some people don't like due to the distance in ratio between 1st and 2nd, but I actually like it because that low 1st gear brings motivation to a big, heavy car. Both transmissions (if before 1987) in their stock condition can withstand a similar amount of power, about the equivalent of a stock TH350.
If I was making the choice, I'd go with the 700R4. Make sure you get a later model one, the ones made before 1985 really aren't good, and the 1987 and later ones have an auxiliary valve body that makes the shift into gear from park or neutral a little less jolting.
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