Th400 shift problem
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Joined: Aug 2004
Posts: 202
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From: Melbourne Florida
Car: 87 Formula
Engine: '00 LM7
Transmission: 4L60e
Axle/Gears: 3.23 posi
Th400 shift problem
I have a th400 with a B&M 3000 stall, B&M cooler, and a shift improver kit.
Yesterday in town my trans started having funny shifting issues. 1-2 seems well enough, except its softer than usual, but 2-3 takes a good half second longer and feels like it is slipping a little while it shifts. I checked fluid right after it happened. It was half a quart low from a leak, but the fluid looked good. I thought it might have been a vacuum issue, but the hose going down to the trans is fairly new and held pressure blowing through it. It's still doing it today and I'm not sure whats up.
anbody with ideas?
Yesterday in town my trans started having funny shifting issues. 1-2 seems well enough, except its softer than usual, but 2-3 takes a good half second longer and feels like it is slipping a little while it shifts. I checked fluid right after it happened. It was half a quart low from a leak, but the fluid looked good. I thought it might have been a vacuum issue, but the hose going down to the trans is fairly new and held pressure blowing through it. It's still doing it today and I'm not sure whats up.
anbody with ideas?
Thread Starter
Member
iTrader: (1)
Joined: Aug 2004
Posts: 202
Likes: 0
From: Melbourne Florida
Car: 87 Formula
Engine: '00 LM7
Transmission: 4L60e
Axle/Gears: 3.23 posi
Re: Th400 shift problem
update. I threw in a big pint of seaform Trans Tune and it doesnt seem to have changed much
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Joined: Nov 2008
Posts: 356
Likes: 1
From: sacramento california
Car: 64chevelle/smokey trans am
Engine: 350 p600 pro charger/350
Transmission: 350/700r4
Axle/Gears: 3.36
Re: Th400 shift problem
the clutches for third(direct) are probably on their way out. you might get a little better if you install a transgo shift kit as it holds third three times as hard. probably a crutch that might not work though. if you feel like it's worth trying atleast if you have to rebuild it the kit would already be in there. you could also increase pump pressure as a crutch by installing another horse shoe clip on the pressure regulator valve in the pump (you could accomplish this with the pan off) or a stiffer shift kit pump spring (again with the pan off).
Last edited by ed o; Feb 8, 2009 at 11:13 PM.
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