1971Chevy Pickup not shifting right - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chazdo2 · 08-15-2016, 07:46 PM

I think I have my engine RPM problem figured out. It is a three speed auto tranny. It seems like its only shifting first and second gear. I guess that would explain me running around 4K RPM's at 55 MPH. Any ideas why the tranny is not shifting up as it should? The vacuum line is hooked to the intake manifold and the tranny.

**LockDoc** · 08-15-2016, 08:58 PM

Quote:

Originally Posted by chazdo2

I think I have my engine RPM problem figured out. It is a three speed auto tranny. It seems like its only shifting first and second gear. I guess that would explain me running around 4K RPM's at 55 MPH. Any ideas why the tranny is not shifting up as it should? The vacuum line is hooked to the intake manifold and the tranny.

Are you sure that your linkage is adjusted correctly? Is the indicator in the park position when the trans is in park?

LockDoc

chazdo2 · 08-16-2016, 01:51 PM

not sure about the linkage. Truck doesn't have the transmission indicator on the column. How do you adjust the linkage?

davepl · 08-16-2016, 01:54 PM

What about the kickdown cable at the carb? If that's disconnected and just pulled taught it'd never upshift, or not till very late. That's about all I can think of.

chazdo2 · 08-16-2016, 02:19 PM

Quote:

Originally Posted by davepl

What about the kickdown cable at the carb? If that's disconnected and just pulled taught it'd never upshift, or not till very late. That's about all I can think of.

where does the kick down cable hook up to?

davepl · 08-16-2016, 02:31 PM

Quote:

Originally Posted by chazdo2

where does the kick down cable hook up to?

Transmission to carb.

Coley · 08-16-2016, 02:35 PM

...have you checked your trans fluid/fill level?
If you are low on fluid it will not shift correctly or quickly.
The level is often hard to read on the trans dipstick...but this is a quick check and fix if it is low.
My two bits.
Coley

leftybass209 · 08-16-2016, 02:47 PM

Everything said above, and do you know your rear end gearing? What's the story with the transmission? Where did it come from? Is it shifting soft, or firm right now? Does it lunge after it shifts?

**kwmech** · 08-16-2016, 05:40 PM

Kick down cable on a T350 does not affect up- shifting

davepl · 08-16-2016, 07:02 PM

Quote:

Originally Posted by kwmech

Kick down cable on a T350 does not affect up- shifting

How does it work?

haycatcher · 08-16-2016, 07:30 PM

Try starting in low gear and manually shift by hand and see how trans responds. Check trans fluid at running temperature with truck in gear with helper so no one gets run over or anything gets run into. Make sure modulator line is not leaking and any rubber on line is not cracked.

Not 100% sure but I think bad modulators will suck out trans fluid.

chazdo2 · 08-17-2016, 09:02 AM

You guys are the best!!!!!!!!!!!!!!!!!!!!!!!!! Cant thank you enough for your time spent with the less learned!!

08-15-2016, 07:46 PM	#1
chazdo2 Registered User Join Date: Mar 2016 Location: auburn new york Posts: 71	1971Chevy Pickup not shifting right I think I have my engine RPM problem figured out. It is a three speed auto tranny. It seems like its only shifting first and second gear. I guess that would explain me running around 4K RPM's at 55 MPH. Any ideas why the tranny is not shifting up as it should? The vacuum line is hooked to the intake manifold and the tranny.

08-16-2016, 01:51 PM	#3
chazdo2 Registered User Join Date: Mar 2016 Location: auburn new york Posts: 71	Re: 1971Chevy Pickup not shifting right not sure about the linkage. Truck doesn't have the transmission indicator on the column. How do you adjust the linkage?

08-16-2016, 01:54 PM	#4
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: 1971Chevy Pickup not shifting right What about the kickdown cable at the carb? If that's disconnected and just pulled taught it'd never upshift, or not till very late. That's about all I can think of. __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

08-16-2016, 02:35 PM	#7
Coley Registered User Join Date: Oct 2011 Location: Victoria, B.C Posts: 3,794	Re: 1971Chevy Pickup not shifting right ...have you checked your trans fluid/fill level? If you are low on fluid it will not shift correctly or quickly. The level is often hard to read on the trans dipstick...but this is a quick check and fix if it is low. My two bits. Coley __________________ ....for some men, there is experience, skill and effort....for the others...there is visa and UPS LOL 1966 Chevy 1/2 ton (Florida- Red/white) 1972 Chevy 1/2 ton (California- Blue/white) 2005 Chevy Silverado HD2500/Duramax 2000 Dodge Ram 1500

08-16-2016, 02:47 PM	#8
leftybass209 Registered User Join Date: Feb 2011 Location: Modesto, CA Posts: 2,189	Re: 1971Chevy Pickup not shifting right Everything said above, and do you know your rear end gearing? What's the story with the transmission? Where did it come from? Is it shifting soft, or firm right now? Does it lunge after it shifts?

08-16-2016, 05:40 PM	#9
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,656	Re: 1971Chevy Pickup not shifting right Kick down cable on a T350 does not affect up- shifting

08-16-2016, 07:30 PM	#11
haycatcher Registered User Join Date: Jul 2001 Location: Youngstown, OH Posts: 95	Re: 1971Chevy Pickup not shifting right Try starting in low gear and manually shift by hand and see how trans responds. Check trans fluid at running temperature with truck in gear with helper so no one gets run over or anything gets run into. Make sure modulator line is not leaking and any rubber on line is not cracked. Not 100% sure but I think bad modulators will suck out trans fluid.

08-17-2016, 09:02 AM	#12
chazdo2 Registered User Join Date: Mar 2016 Location: auburn new york Posts: 71	Re: 1971Chevy Pickup not shifting right You guys are the best!!!!!!!!!!!!!!!!!!!!!!!!! Cant thank you enough for your time spent with the less learned!!



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