400 Transmisison Issues - The 1947 - Present Chevrolet & GMC Truck Message Board Network

skokie · 03-01-2005, 04:57 PM

Here is the original thread on the problem.
http://67-72chevytrucks.com/vboard/s....php3?t=140978
Wuick summary here: With the truck in D if you punch it it kicks down to 2nd but when you let off the gas it will not shift backinto 3rd unless you take it out of D drop it either into N or 2 and back to D but if you put it in 2 and punch it it kicks down to 1st and goes back into 2nd when you let off of the gas. The entire tranny has been swapped out. Flexplate, torque converter, valve body, internal kickdown switch and external kickdown switch has been swapped (lokar). Also the vac modulator and governor in the replacement tranny are new. The tranny guy is stumped and cant figure it out. He says he called a tranny association and asked them about this and they said swap out the valve body which he did and same problem. If anyone can think of anything else please post it up.

Thanks

skokie · 03-01-2005, 08:40 PM

Talked to the tranny guy and he is going to try a shift kit. Not sure why but hey its free.

skokie · 03-01-2005, 11:28 PM

Ttt

03-01-2005, 04:57 PM	#1
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,354	400 Transmisison Issues Here is the original thread on the problem. http://67-72chevytrucks.com/vboard/s....php3?t=140978 Wuick summary here: With the truck in D if you punch it it kicks down to 2nd but when you let off the gas it will not shift backinto 3rd unless you take it out of D drop it either into N or 2 and back to D but if you put it in 2 and punch it it kicks down to 1st and goes back into 2nd when you let off of the gas. The entire tranny has been swapped out. Flexplate, torque converter, valve body, internal kickdown switch and external kickdown switch has been swapped (lokar). Also the vac modulator and governor in the replacement tranny are new. The tranny guy is stumped and cant figure it out. He says he called a tranny association and asked them about this and they said swap out the valve body which he did and same problem. If anyone can think of anything else please post it up. Thanks __________________ RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234

03-01-2005, 08:40 PM	#2
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,354	Talked to the tranny guy and he is going to try a shift kit. Not sure why but hey its free. __________________ RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234

03-01-2005, 11:28 PM	#3
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,354	Ttt __________________ RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234



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