700R4 build thread. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

WTO · 11-16-2020, 01:57 PM

Looking for some ideas on how to correct line pressure flutter in 3rd or 4th over 1/2 throttle. Gauge bounces from 125-200PSI rapidly. I see it was recommended not to block the line bias valve, I'm confident that is the cause of my pressure problem.
Trans is in a 68 C2500, 4:11 gears and worn out 327. I have a 355 ready to go in but want the trans 100% 1st.
Valve body modifications were the transgo SK700 kit. I went back and reduced the boost valve from .500 to the next one down, .475 I believe. This improved shift feel but did not fix the line pressure flutter.
TV cable geometry is set up properly. The trans works/shifts perfect, without a pressure gauge you would never know there was a problem.

11-16-2020, 01:57 PM	#28
WTO Registered User Join Date: Aug 2013 Location: Kennesaw, GA Posts: 11	Re: 700R4 build thread-Line bias valve Looking for some ideas on how to correct line pressure flutter in 3rd or 4th over 1/2 throttle. Gauge bounces from 125-200PSI rapidly. I see it was recommended not to block the line bias valve, I'm confident that is the cause of my pressure problem. Trans is in a 68 C2500, 4:11 gears and worn out 327. I have a 355 ready to go in but want the trans 100% 1st. Valve body modifications were the transgo SK700 kit. I went back and reduced the boost valve from .500 to the next one down, .475 I believe. This improved shift feel but did not fix the line pressure flutter. TV cable geometry is set up properly. The trans works/shifts perfect, without a pressure gauge you would never know there was a problem. __________________ 1968 GMC Custom Camper, 1 owner 2005 GTO 2015 GMC All Terrain



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