TH-400 Questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jdheff1982 · 10-01-2011, 11:54 AM

Hello,

My truck has a TH-400 tranny and I am experiencing some odd functionality of the unit.

If I am cruising and suddenly stomp on the gas, the engine gets louder, but the RPM's do not increase nor does the tranny kick-down. The engine is not suffering from lack of power or what not. Also, the tranny won't shift from 1st to 2nd until the engine hits about 2500 RPM's no matter where my foot is on the gas.

Last thing, what can I do about column shift slop? And how do I get the gear selector indicator to work? I have tried to reclip it to the plastic sleeve, but it gets pulled off easily.

Thanks.

**old Rusty C10** · 10-01-2011, 06:08 PM

check the fluid level and color if its low add some if its brown and burnt start saving for a new trans.. if its brown and not burnt smelling change it and the filter..
the only way youre fixint the thing with the indicator is to either tighten the clip or replace the part of the coumn it rides on

MikeJones16 · 10-01-2011, 06:43 PM

what he said^

If the gear selector move around but kinda gets "lost" your little wire could be snapped or loose.

Dunenutt · 10-01-2011, 07:23 PM

For the first to second shift, check the modulator, or just replace it (they are cheap).
The kickdown, check the kckdown switch. Check for 12v at the connector on the trans at full throttle. While it's not running, but ignition on.

jdheff1982 · 10-01-2011, 07:35 PM

The fluid and filter were replaced 2 months ago.

The gear selector is still intact, just the clip won't hold.

I will definitely have a look at the kick down switch and solenoid.

Thanks
Posted via Mobile Device

10-01-2011, 11:54 AM	#1
jdheff1982 Registered User Join Date: Aug 2011 Location: Wichita, KS Posts: 318	TH-400 Questions Hello, My truck has a TH-400 tranny and I am experiencing some odd functionality of the unit. If I am cruising and suddenly stomp on the gas, the engine gets louder, but the RPM's do not increase nor does the tranny kick-down. The engine is not suffering from lack of power or what not. Also, the tranny won't shift from 1st to 2nd until the engine hits about 2500 RPM's no matter where my foot is on the gas. Last thing, what can I do about column shift slop? And how do I get the gear selector indicator to work? I have tried to reclip it to the plastic sleeve, but it gets pulled off easily. Thanks. __________________ Project and Truck Specs: http://67-72chevytrucks.com/vboard/s...d.php?t=483381

10-01-2011, 06:08 PM	#2
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: TH-400 Questions check the fluid level and color if its low add some if its brown and burnt start saving for a new trans.. if its brown and not burnt smelling change it and the filter.. the only way youre fixint the thing with the indicator is to either tighten the clip or replace the part of the coumn it rides on __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

10-01-2011, 06:43 PM	#3
MikeJones16 Registered User Join Date: Sep 2010 Location: Saskatoon, SK Posts: 244	Re: TH-400 Questions what he said^ If the gear selector move around but kinda gets "lost" your little wire could be snapped or loose. __________________ http://67-72chevytrucks.com/vboard/s...d.php?t=429098

10-01-2011, 07:23 PM	#4
Dunenutt Newbee Join Date: Jan 2010 Location: Phoenix, Arizona Posts: 1,406	Re: TH-400 Questions For the first to second shift, check the modulator, or just replace it (they are cheap). The kickdown, check the kckdown switch. Check for 12v at the connector on the trans at full throttle. While it's not running, but ignition on. __________________ My Build, http://67-72chevytrucks.com/vboard/s...58#post4464158

10-01-2011, 07:35 PM	#5
jdheff1982 Registered User Join Date: Aug 2011 Location: Wichita, KS Posts: 318	Re: TH-400 Questions The fluid and filter were replaced 2 months ago. The gear selector is still intact, just the clip won't hold. I will definitely have a look at the kick down switch and solenoid. Thanks Posted via Mobile Device __________________ Project and Truck Specs: http://67-72chevytrucks.com/vboard/s...d.php?t=483381

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