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#1 |
Registered User
Join Date: Jan 2007
Location: Canton, TX
Posts: 210
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Turbo 400 Issues
Here's what its doing. Reverse is perfect, when you put in in 1st its fine, put it in second it shifts from 1st to second fine the first time but when you come to a stop and take off it starts in second. When you put it in drive it does the same thing, the first time it shifts butter smooth, but from then on when you come to a stop it wants to start out in 2nd instead of 1st. Fluid looks good. One sidenote. I did just have the carb rebuilt b4 this started. Thanks in advance
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1969 ![]() ![]() Last edited by gmc1969custom; 12-04-2008 at 03:48 PM. |
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#2 |
It's a catastrophic success.
![]() Join Date: Jan 2003
Location: Oklahoma
Posts: 2,077
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Re: Turbo 400 Issues
I know if the vac line is leaking or unhooked it will cause it to not shift "up" but it might be something to check.
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#3 |
Registered User
Join Date: Jun 2008
Location: South Florida
Posts: 11,375
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Re: Turbo 400 Issues
Check the kickdown cable where it connects to the carburator...
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Get your facts first, and then you can distort them as much as you please!!!!!. Sylvester's build thread >>>http://67-72chevytrucks.com/vboard/s...ht=big+rebuild |
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#4 |
its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,693
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Re: Turbo 400 Issues
there is no kick down cable on a TH400, and even if it did, it would not do this... same with the vac modulator... it would be staying in first till about 5000 RPM till is would slam into 2nd.
However... I don't even have a good theory on what it could be though. Last edited by Longhorn Man; 12-04-2008 at 04:34 PM. |
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#5 | |
Registered User
Join Date: Jan 2006
Location: Dallas
Posts: 504
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Re: Turbo 400 Issues
Quote:
Yes the kickdown is electronic and wouldn't affect this. If the modulator is disconnected, it wouldn't shift right, but I am wondering if the modulator is conneced but somehow messing up since the modulator does affect the upshifting? Possibly a small vaccum leak?
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_______________ Thomas '78 Silverado '74 Monte Carlo '47 Teardrop Trailer East Texas Classics Local Club |
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#6 |
Senior Member
Join Date: Jul 2001
Location: Muskegon,MI,USA
Posts: 6,026
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Re: Turbo 400 Issues
I have had a problem like this with a TH 400 and it turned out to be a sticky governor valve. The spool valve would stick and not return. A good burnishing and cleaning of the spool fixed the problem. ( I used 1500 grit paper to polish the spool).
Jim
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1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC |
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#7 |
1971 GMC 3/4 ton, 572 CID
Join Date: Aug 2007
Location: Green Bay, WI
Posts: 293
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Re: Turbo 400 Issues
I agree with JimK, I've seen this problem a couple of times
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71 GMC 3/4 572 CID, 1988 GMC 1/2 2006 Saturn Vue "We always have parts left over on a job this size" |
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#8 |
Fabricate till you "puke"
Join Date: Jun 2002
Location: Ill
Posts: 9,403
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Re: Turbo 400 Issues
3rd that.....it sounds like the govenor is hangin. crazyL
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69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... |
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#9 |
Registered User
Join Date: Jan 2007
Location: Canton, TX
Posts: 210
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Re: Turbo 400 Issues
Ok, I will check the governor out and see what I can figure out. Thanks for the help so far.
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1969 ![]() ![]() Last edited by gmc1969custom; 12-05-2008 at 10:18 AM. |
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