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12-06-2003, 07:29 PM
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#1 |
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Registered User
Join Date: Oct 2003
Location: CT
Posts: 315
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TH400 Not shifting
The 400 in my dads plow truck (84K30 6.2L Diesel NP208) shifts into second hard, and wont shift into third. Its not slipping at all. I was thinking it the Vac. modulator, but where under the hood does it hook up? Is there a pump or something that makes vacuum?
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Anthony 07 Tahoe LT 70 Chevelle 450HP 383-TH400 77 GMC Royal Sierra~Resto in progress~ |
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12-07-2003, 10:35 AM
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#2 |
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Registered User
Join Date: Apr 2003
Location: New Mexico. Of all places for an Island boy.
Posts: 180
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Look behind the carb at the intake manifold, you should be able to follow the vacuum line up from the tranny. Runs infront of the distrubitor. Good Luck...Jon
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12-07-2003, 06:03 PM
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#3 |
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Registered User
Join Date: Nov 2002
Posts: 272
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what I would do is start at the modulator and follow the line to where it connects to the engine
If the line hasnt come off the modulator pull it off and see if there is any trans fluid in the line or comming from the modulator. If so replace it. If not start looking at the other componets. |
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12-08-2003, 01:55 AM
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#4 |
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Account Suspended
Join Date: Oct 2002
Location: Elkhart, IN
Posts: 6,399
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TH400 doesnt have a vac modulator, if i remember correctly.
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12-08-2003, 03:54 AM
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#5 |
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Right turn Clyde
Join Date: Nov 2002
Location: Cincinnati, Ohio
Posts: 2,911
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TH350s and TH400s have modulator valves, though you might be thinking about the different kickdown setups. TH350 is cable and TH400 is an electric solenoid.
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1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI |
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12-08-2003, 04:36 AM
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#6 |
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Registered User
Join Date: Sep 2003
Location: Twin Falls, Idaho
Posts: 73
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TH 400 no shift
It is hard to kill a Turbo 400 trans. Most shift problems are caused by defective govenor. This is a device on right side of trans under round cover with 4 bolts.
Pull th govenor straight out. Look device over and check for any bent, broken or changed parts. Most repair manuals will give an overview and some check points. The most important consideration is the weights and valve MUST move freely. A used unit is as good as a new unit. If unit has any metal missing, a filter and fluid change are needed.... The govenor is on the side of the trans case NOT in oil pan.......
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Chevy stepper 400sb 350 turbo |
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12-08-2003, 01:19 PM
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#7 |
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Slots go on anything!
Join Date: May 2003
Location: Richardson, TX
Posts: 5,957
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It seems like the vacuum pump is towards the front of the engine on a 6.2 . It has been a long time since I have looked at one, but that seems right.
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1974 Jimmy- 5.3/4L80e/NP241 |
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