TH350 vs. TH400 Case/Interchangeability?
a th350 is like a 4l60e and a th400 is like a 4l80e the actual size is the biggest difference. kind of like a 10 bolt to a 9 inch lol. a th350 is plenty strong for most peoples applications, a th400 has the benifit of more reliability and probably wont have to be torn down and rebuilt as much as a th350 on big horsepower. it really comes down to what you plan for the car
Thread Starter
Registered User
Joined: Mar 2017
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Would anyone know what trans. would be in my 1978 Chevy 1/2 ton 4x4
350 cid? It's been taking 15 minutes to move after it sets for a day. Now it doesn't move at all. The tranny fluid is dark and smells burned. Is the tranny shot or is it the converter?
Thanks, gregjo1948
350 cid? It's been taking 15 minutes to move after it sets for a day. Now it doesn't move at all. The tranny fluid is dark and smells burned. Is the tranny shot or is it the converter?
Thanks, gregjo1948
TECH Junkie
Joined: May 2012
Posts: 3,047
Likes: 714
From: Poplarville, MS
Most likely the trans is shot. The dark and burnt fluid comes from clutches, most 350/400 torque converts did not have clutches in them until the later models. The turbo 350 has a modulator valve at the rear of the trans and points to the rear of the vehicle. The turbo 400 has a modulator valve on the side of the trans and points to the side. And no they are not the same case.
