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I have rebuilt many th350 trannies so it is nothing new to me. Last night I rebuilt one but it was different. Each clutch pack had one less clutch per pack than all the other 350 trannies that I have done. I assume this is just a "lightweight" th350 design. Every bit of the transmission inside and out was IDENTICAL to a "regular" th350 except for the one less clutch per clutch pack. Is this one of those th275's.
Thanks Again For The Help. Will, N.B.tx.
 

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Fred has a point I forgot about I had a 350 backed by a t350 In a wagon a long time back when it finally died (the tranny) I had a friend rebuild who did trannys for a living he said it was a 6 cylinder tranny someone probably got from a bone yard and explained it had less clutches MIKE
 

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One way to tell the difference is by the apply piston, if it is a thick one it is for an L4-L6- V6- or a small V8 less friction plates.The thiner the piston the more plates.Also if it is a 250 or 250c it will have an external band ajustment on the right side between the cooler fittings and the 1-2 accumulator.With the code I can probably tell you what car it came out of...FRED
 

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Yeah, most folks think a 350 is a 350 is a 350. Or a 400 is a 400 is a 400. In reality, there are countless differences in number of clutch discs, shift timing, tailshaft length, etc. Early transmissions tend to use cast drums to house the clutches, later trannies sometimes use stamped sheet metal drums. GM thinks the stamped drums are just as strong as cast ones. I don't.

A 250 is similar to a 350 except that a band replaces one set of clutches. Some of 'em were air cooled, with no trans cooler tubes.

A 250c or 350c uses a lockup torque converter. No lockup available on the 400's. Some early 400's had a two position stator in the converter which is -almost- like having a fourth gear! Using a manual override, or a custom built "brain box" from Bruce Roe, can turn this into a pseudo six speed.

A 375 was a light duty TH 400 that had few clutch discs and a smaller output shaft. The 375B was a 350 with EXTRA clutch discs.

A TH 475 is a variation of the 400. They had a bunch of clutch discs, and straight cut planetary gears that were extra strong, but noisy. (like the M-22 rock crusher manual tranny.) The 475's went into motor home and school bus chassis.

The 425 was a front wheel drive version of the 400, and (I think) had the planetaries cut at the reverse angle, because they spun the opposite direction as a 400. The 425 also had the one way clutch on the direct clutch drum activate in the opposite direction. The 425 ONLY went behind big engines, so they were built with high torque capacity. If you can find a direct clutch drum out of a 425, spin the one way clutch upside down and stick it in the TH 400 in your Chevelle! If the one way clutch is backwards, things are gonna get real expensive in a hurry.

These sort of variations apply to most automatics. If performance is important to you, you need to check with a tranny expert to figure out the best set of compromises for you.
 
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