Th350 3 speed odd shifting - The 1947 - Present Chevrolet & GMC Truck Message Board Network

zacharywest34 · 08-27-2016, 06:42 PM

Hi everyone, my th350 trans on my truck seems to be shifting strange. It has very long drawn out shifts and when it does shift it shifts in hard. it goes from 1-2 at about 20-25 mph and 2-3 at about 50 or later mph. It only started happening a couple days ago. I checked fluid and it is right where it should be and red in color. The trans is original to the 1971 c20 and not sure when the last time it was looked over. Any ideas on where i should start looking?
Thanks
Zach

franken · 08-27-2016, 08:15 PM

Common issue is a vacuum leak or no vacuum to the modulator. Another is the trans is isn't in drive.

08-27-2016, 06:42 PM	#1
zacharywest34 Registered User Join Date: Mar 2015 Location: Naperville, Illinois Posts: 55	Th350 3 speed odd shifting Hi everyone, my th350 trans on my truck seems to be shifting strange. It has very long drawn out shifts and when it does shift it shifts in hard. it goes from 1-2 at about 20-25 mph and 2-3 at about 50 or later mph. It only started happening a couple days ago. I checked fluid and it is right where it should be and red in color. The trans is original to the 1971 c20 and not sure when the last time it was looked over. Any ideas on where i should start looking? Thanks Zach __________________ 1971 C20 350sbc mild cam Daily driver

08-27-2016, 08:15 PM	#2
franken Registered User Join Date: Jun 2013 Location: Somewhere Posts: 3,130	Re: Th350 3 speed odd shifting Common issue is a vacuum leak or no vacuum to the modulator. Another is the trans is isn't in drive.



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