350 wont shift out of first... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

fotoboy · 02-14-2024, 06:20 PM

So... I have a transmission question... I have a 1980 Scotsdale with a (newly rebuilt) 350 and a (newly rebuilt) turbo 350 tranny.

It was shifting fine (beautifully actually), then I installed a manual choke kit on the QJ. Now when I drive it, it does not shift out of first, it acts like it wants to, or is starting to, then it lurches as if it were downshifting, which is bizarre.

When I manually put it in 1st, it doesnt malfunction, but will not shift to second if I manually shift it to 2nd. Thoughts?

Oh... Vac line is good and attached (i made sure it was clear, not clogged but didnt test otherwise), Modulator is new with rebuild...

**old Rusty C10** · 02-15-2024, 04:01 PM

are you sure the new modulator is good.. ive seen several new in box parts be bad from the chinese factory.. and the rubber on the line ends is that in good shape?

geezer#99 · 02-15-2024, 07:03 PM

Nice wheel pic but a pic of the motor might help.

**dmb** · 02-15-2024, 07:52 PM

did you move the detent cable

v30crewcab · 02-15-2024, 10:51 PM

unhook the detent cable and try it.

fotoboy · 02-25-2024, 08:00 PM

Quote:

Originally Posted by dmb

did you move the detent cable

yes, but completely replaced and adjusted it , also ran it without cable and it ran the same.

fotoboy · 02-25-2024, 08:00 PM

Quote:

Originally Posted by v30crewcab

unhook the detent cable and try it.

check. no difference.

fotoboy · 02-25-2024, 08:01 PM

Quote:

Originally Posted by old Rusty C10

are you sure the new modulator is good.. ive seen several new in box parts be bad from the chinese factory.. and the rubber on the line ends is that in good shape?

fair enough. replaced the modulator and got same result.

fotoboy · 02-25-2024, 08:08 PM

Quote:

Originally Posted by geezer#99

Nice wheel pic but a pic of the motor might help.

sure, I didnt think the engine photos would matter, dealing with the transmission...

fotoboy · 02-25-2024, 08:08 PM

I also have a video if anybody thinks it would help...

geezer#99 · 02-25-2024, 08:19 PM

Sure, play it.

Does your choke blade open all the way with the choke knob pushed in all the way?

**dmb** · 02-25-2024, 08:46 PM

the detent cable ib not adjusted , it is all the way in , it would act like it was at wot all the time. pull up the plunger and hold the throttle wide open then push the plunger down

fotoboy · 02-26-2024, 10:33 AM

Quote:

Originally Posted by geezer#99

Sure, play it.

Does your choke blade open all the way with the choke knob pushed in all the way?

Yes, but how does a choke effect the transmission?

fotoboy · 02-26-2024, 10:43 AM

Quote:

Originally Posted by dmb

the detent cable ib not adjusted , it is all the way in , it would act like it was at wot all the time. pull up the plunger and hold the throttle wide open then push the plunger down

That is exactly how I adjusted it... (it is not the OEM cable) and is hard to see in the photo... (submitting new photo) but will double check that anyway. Thanks

geezer#99 · 02-26-2024, 04:42 PM

Disconnect your manual choke set up and wire the choke wide open then test drive it.

fotoboy · 02-26-2024, 07:09 PM

Quote:

Originally Posted by geezer#99

Disconnect your manual choke set up and wire the choke wide open then test drive it.

Ok, for fun I tried that, no difference what so ever.

geezer#99 · 02-26-2024, 08:02 PM

Time to explore yours transmission warranty.
Could be governor.

Shifty One · 03-01-2024, 07:12 PM

Quote:

Originally Posted by old Rusty C10

are you sure the new modulator is good.. ive seen several new in box parts be bad from the chinese factory.. and the rubber on the line ends is that in good shape?

It took me quite few to get one that works right....

Accelo · 03-02-2024, 02:54 AM

Sometimes the plastic gear on the governor shears. Pull the governor and check.

Axle · 03-02-2024, 08:45 AM

Do you have a metal line to your vacuum modulator (just rubber line for connections)? If not, the vacuum will suck the line shut.

Vacuum connected to a manifold vacuum source? If connected to a carb make sure you are not on a ported line.

You can drive a th350 with the kickdown cable disconnected (its not a tv cable like an overdrive trans). When you disconnect the kickdown cable does it spring/pull back towards the trans? (too tight if it does).

02-14-2024, 06:20 PM	#1
fotoboy Registered User Join Date: May 2013 Location: manhattan ks Posts: 9	350 wont shift out of first... So... I have a transmission question... I have a 1980 Scotsdale with a (newly rebuilt) 350 and a (newly rebuilt) turbo 350 tranny. It was shifting fine (beautifully actually), then I installed a manual choke kit on the QJ. Now when I drive it, it does not shift out of first, it acts like it wants to, or is starting to, then it lurches as if it were downshifting, which is bizarre. When I manually put it in 1st, it doesnt malfunction, but will not shift to second if I manually shift it to 2nd. Thoughts? Oh... Vac line is good and attached (i made sure it was clear, not clogged but didnt test otherwise), Modulator is new with rebuild... Attached Images

02-15-2024, 04:01 PM	#2
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,259	Re: 350 wont shift out of first... are you sure the new modulator is good.. ive seen several new in box parts be bad from the chinese factory.. and the rubber on the line ends is that in good shape? __________________ 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!!

02-15-2024, 07:03 PM	#3
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,512	Re: 350 wont shift out of first... Nice wheel pic but a pic of the motor might help.

02-15-2024, 07:52 PM	#4
dmb Active Member Join Date: Sep 2023 Location: randolph va Posts: 121	Re: 350 wont shift out of first... did you move the detent cable

02-15-2024, 10:51 PM	#5
v30crewcab Registered User Join Date: Apr 2012 Location: Chatt Tn Posts: 957	Re: 350 wont shift out of first... unhook the detent cable and try it. __________________ 88 military v30 crewcab shortbed 5.9 cummins, nv4500, 205 86 k30, 89 diesel burb, 76 gmc pathfinder 71 longbed 5.3 4l80 http://67-72chevytrucks.com/vboard/s...d.php?t=522535

02-25-2024, 08:08 PM	#10
fotoboy Registered User Join Date: May 2013 Location: manhattan ks Posts: 9	Re: 350 wont shift out of first... I also have a video if anybody thinks it would help...

02-25-2024, 08:19 PM	#11
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,512	Re: 350 wont shift out of first... Sure, play it. Does your choke blade open all the way with the choke knob pushed in all the way?

02-25-2024, 08:46 PM	#12
dmb Active Member Join Date: Sep 2023 Location: randolph va Posts: 121	Re: 350 wont shift out of first... the detent cable ib not adjusted , it is all the way in , it would act like it was at wot all the time. pull up the plunger and hold the throttle wide open then push the plunger down

02-26-2024, 04:42 PM	#15
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,512	Re: 350 wont shift out of first... Disconnect your manual choke set up and wire the choke wide open then test drive it.

02-26-2024, 08:02 PM	#17
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,512	Re: 350 wont shift out of first... Time to explore yours transmission warranty. Could be governor.

03-02-2024, 02:54 AM	#19
Accelo Registered User Join Date: Mar 2015 Location: washington Posts: 2,159	Re: 350 wont shift out of first... Sometimes the plastic gear on the governor shears. Pull the governor and check.

03-02-2024, 08:45 AM	#20
Axle Registered User Join Date: Jul 2011 Location: SW Ontario Posts: 1,199	Re: 350 wont shift out of first... Do you have a metal line to your vacuum modulator (just rubber line for connections)? If not, the vacuum will suck the line shut. Vacuum connected to a manifold vacuum source? If connected to a carb make sure you are not on a ported line. You can drive a th350 with the kickdown cable disconnected (its not a tv cable like an overdrive trans). When you disconnect the kickdown cable does it spring/pull back towards the trans? (too tight if it does).



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.