A 400 automatic transmission question (passing gear)

goatman · 07-09-2008, 06:20 PM

Hi, i have a 86 C-20 pickup with the 400 automatic transmission that won't go into passing gear. I can't remember if this year/model tranny had a kickdown or detent cable on it. Mine doesn't have one so im wondering if thats the problem.....however it does have a modulator. Thanks in advance.

75K30 · 07-09-2008, 06:59 PM

Th 400's use an electric slide switch that activates the downshift capability.
No cables like the 350.
Electrical wire is what you are looking for. The connector can fail, or just fall off.

goatman · 07-11-2008, 09:36 AM

Hi again...I located the orange wire on transmission and traced it back to a slide switch on the accellerator pedal. How do i test to see if switch is defective. Should i just hook up a voltmeter and move the slide on the switch and see if it reads 12volts or is there another way.

75K30 · 07-11-2008, 09:58 AM

Yes, you should have 12vdc at one end of the switch, and the orange wire that goes to the trans will have nothing until that switch is made, or closed.
Many times I have had to install a piece of tubing over the round portion of the slide to make the switch activate sooner.
I suspect that you are lacking 12 volts. Should be an easy repair.

goatman · 07-12-2008, 07:33 AM

Thanks for the help, thats exactly what the problem was. The pedal when fully pressed wasn't pushing the slide down far enough to make the contacts. Thanks again for the help.

goatman john

75K30 · 07-12-2008, 08:42 AM

Right on man. Glad to be of assistance.......

gmctrucks · 07-12-2008, 07:21 PM

I remember finding mine disconnected on my 1970 GTO boy did it help when I connected it.

75K30 · 07-12-2008, 07:29 PM

Quote:

Originally Posted by gmctrucks

I remember finding mine disconnected on my 1970 GTO boy did it help when I connected it.

I guess we can Hijack this thread, since it is pretty dead anyway.
You had a 70 Goat?
I had a 70 with a 455, and a 69 with a 400 (Ram air IV) yes a IV. While not original to the car, it was a real nnce ride I put together.
Also had a 67 at the time, and a 10 second all steel 65 with Pontiac power, and steel heads. WOW!
Gotta dig up some pics of those things. I kinda miss my old "Tin Indians"!

gmctrucks · 07-13-2008, 06:42 AM

75K30 I bought the car on my 16 birthday I was one happy young-in my engine was the one that was rated with 350HP I had the fasts car in high school only one car beat me it was in another city this guy had a 68 Camero with a high lift cam and some huge tires on the rear my problem with my car it had a 323 open rear end I couldn't take off and the guy only wanted to race from a dead stop I remember coming up to this red light and there was a 74 T/A and a Comet Grabber well the light turned green and I had just stopped so they got a start on me well I caught up to them and beat both of them the next day the guy in the 74 T/A was a tech at this dealership where my dad was service manager I worked there as well he told my dad boy does you son have a fast car. Here's another one I once raced this Charger with a 440 now he had a posi unit on his car it' s just that he couldn't take off well 20 some years had passed and I was back in my home town having a Magnaflow put on my truck when someone tapped on my back it was the same guy he said you know that your GTO was the only car that ever beat me well my son was about 12 he said dad your was that fast I said it sure was I have many more stories but my arm is hurting I bet you have a lot of them as well. SORRY for high ******* again. Be good! GMC
PS-My little brother is looking at this 2006 GTO today I know him it's going to be his it's the brother that I have posted his truck at the track some time ago.

07-09-2008, 06:20 PM	#1
goatman Full Member Join Date: May 2008 Location: nw georgia.....Euharlee Posts: 32	A 400 automatic transmission question (passing gear) Hi, i have a 86 C-20 pickup with the 400 automatic transmission that won't go into passing gear. I can't remember if this year/model tranny had a kickdown or detent cable on it. Mine doesn't have one so im wondering if thats the problem.....however it does have a modulator. Thanks in advance.

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07-09-2008, 06:59 PM	#2
75K30 Senior Member Join Date: Jul 2006 Posts: 3,292	Th 400's use an electric slide switch that activates the downshift capability. No cables like the 350. Electrical wire is what you are looking for. The connector can fail, or just fall off.

07-11-2008, 09:36 AM	#3
goatman Full Member Join Date: May 2008 Location: nw georgia.....Euharlee Posts: 32	Hi again...I located the orange wire on transmission and traced it back to a slide switch on the accellerator pedal. How do i test to see if switch is defective. Should i just hook up a voltmeter and move the slide on the switch and see if it reads 12volts or is there another way.

07-11-2008, 09:58 AM	#4
75K30 Senior Member Join Date: Jul 2006 Posts: 3,292	Yes, you should have 12vdc at one end of the switch, and the orange wire that goes to the trans will have nothing until that switch is made, or closed. Many times I have had to install a piece of tubing over the round portion of the slide to make the switch activate sooner. I suspect that you are lacking 12 volts. Should be an easy repair.

07-12-2008, 07:33 AM	#5
goatman Full Member Join Date: May 2008 Location: nw georgia.....Euharlee Posts: 32	Thanks for the help, thats exactly what the problem was. The pedal when fully pressed wasn't pushing the slide down far enough to make the contacts. Thanks again for the help. goatman john

07-12-2008, 08:42 AM	#6
75K30 Senior Member Join Date: Jul 2006 Posts: 3,292	Right on man. Glad to be of assistance.......

07-12-2008, 07:21 PM	#7
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,635	I remember finding mine disconnected on my 1970 GTO boy did it help when I connected it.

07-13-2008, 06:42 AM	#9
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,635	75K30 I bought the car on my 16 birthday I was one happy young-in my engine was the one that was rated with 350HP I had the fasts car in high school only one car beat me it was in another city this guy had a 68 Camero with a high lift cam and some huge tires on the rear my problem with my car it had a 323 open rear end I couldn't take off and the guy only wanted to race from a dead stop I remember coming up to this red light and there was a 74 T/A and a Comet Grabber well the light turned green and I had just stopped so they got a start on me well I caught up to them and beat both of them the next day the guy in the 74 T/A was a tech at this dealership where my dad was service manager I worked there as well he told my dad boy does you son have a fast car. Here's another one I once raced this Charger with a 440 now he had a posi unit on his car it' s just that he couldn't take off well 20 some years had passed and I was back in my home town having a Magnaflow put on my truck when someone tapped on my back it was the same guy he said you know that your GTO was the only car that ever beat me well my son was about 12 he said dad your was that fast I said it sure was I have many more stories but my arm is hurting I bet you have a lot of them as well. SORRY for high ******* again. Be good! GMC PS-My little brother is looking at this 2006 GTO today I know him it's going to be his it's the brother that I have posted his truck at the track some time ago.