Author Topic: Any chance that no 2nd gear in a TH400 is an easy fix?  (Read 2022 times)

Offline zieg85

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Any chance that no 2nd gear in a TH400 is an easy fix?
« on: December 24, 2013, 02:17:34 PM »
As asked in the subject line, what is the consensus?  1st and 2nd when manually shifted it stays in first, pop it in D and it goes in 3rd.  When in drive it goes from 1st to 3rd.
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
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Offline Displaced_Txn

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Re: Any chance that no 2nd gear in a TH400 is an easy fix?
« Reply #1 on: December 24, 2013, 02:18:33 PM »
what color is the fluid and does it smell burnt

Offline zieg85

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Re: Any chance that no 2nd gear in a TH400 is an easy fix?
« Reply #2 on: December 24, 2013, 02:27:49 PM »
what color is the fluid and does it smell burnt

More red but is a reddish brown.  It smells just like fresh ATF
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline Engineer

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Re: Any chance that no 2nd gear in a TH400 is an easy fix?
« Reply #3 on: December 24, 2013, 02:29:27 PM »
You might try dropping the valve body to see if your 2-3 shift valve is stuck in the upshift position.

But yeah, check your fluid first. After that pull the modulator to make sure there is no fluid in the vacuum line.

Your governor is ok or you wouldn't get any upshift at all.
2002 Chevy 2500HD 4x4 8.1/ZF6sp RC/LB
2001 Chevy 2500HD 4x4 6.0/4L85E EC/SB
1997 Chevy Blazer 4x4
1994 Chevy K-2500 4x4 C6P 5.7/4L80E
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1977 Chevy K-30 4x4 4sp 4.10 454

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Offline Engineer

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Re: Any chance that no 2nd gear in a TH400 is an easy fix?
« Reply #4 on: December 24, 2013, 02:31:05 PM »
After thought, you have something wrong in your valve body because even in manual 1 the TH400 will upshift after you exceed 20mph.
2002 Chevy 2500HD 4x4 8.1/ZF6sp RC/LB
2001 Chevy 2500HD 4x4 6.0/4L85E EC/SB
1997 Chevy Blazer 4x4
1994 Chevy K-2500 4x4 C6P 5.7/4L80E
1979 Chevy K-30 4x4 4sp 4.10
1977 Chevy K-30 4x4 4sp 4.10 454

Dad of an Eagle Scout, and a Life Scout

Offline Engineer

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Re: Any chance that no 2nd gear in a TH400 is an easy fix?
« Reply #5 on: December 24, 2013, 02:34:23 PM »
If you upshift up to 3rd then manually select 2nd do you get a downshift?
2002 Chevy 2500HD 4x4 8.1/ZF6sp RC/LB
2001 Chevy 2500HD 4x4 6.0/4L85E EC/SB
1997 Chevy Blazer 4x4
1994 Chevy K-2500 4x4 C6P 5.7/4L80E
1979 Chevy K-30 4x4 4sp 4.10
1977 Chevy K-30 4x4 4sp 4.10 454

Dad of an Eagle Scout, and a Life Scout

Offline zieg85

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Re: Any chance that no 2nd gear in a TH400 is an easy fix?
« Reply #6 on: December 24, 2013, 02:46:21 PM »
If you upshift up to 3rd then manually select 2nd do you get a downshift?

I have not tried that but I drive it easy and I find if need a little more "go" it downshifts back into first and the engine RPM's have gone higher than that old truck's engine should...
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/