C6 shifting?
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Junior User
Joined: Jan 2008
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C6 shifting?
Hey guys,
I have recently installed a built 69 460 in my 86 f250. I had my C6 rebuilt with 5 clutch pack and 2000 rpm converter. Tranny has nice quick shifts with little or no overlap. Now that the motor is pretty well broke in I tried an experiment. From almost a dead stop, at the bottom of a pretty steep hill I floored the gas. Truck took off great a little wheel spin, made the shift from first to second. About when I expected the second to third gear shift it did not shift. It kinda waffled without making the shift until I pedaled the gas then it dropped into third. Is this a case of not enough vacuum at WOT? The cam is not too wild, just a little lump at idle. Is this an adjustment that could be made with the screw in the vacuum diaphram? Thanks for any advise.
I have recently installed a built 69 460 in my 86 f250. I had my C6 rebuilt with 5 clutch pack and 2000 rpm converter. Tranny has nice quick shifts with little or no overlap. Now that the motor is pretty well broke in I tried an experiment. From almost a dead stop, at the bottom of a pretty steep hill I floored the gas. Truck took off great a little wheel spin, made the shift from first to second. About when I expected the second to third gear shift it did not shift. It kinda waffled without making the shift until I pedaled the gas then it dropped into third. Is this a case of not enough vacuum at WOT? The cam is not too wild, just a little lump at idle. Is this an adjustment that could be made with the screw in the vacuum diaphram? Thanks for any advise.
Laughing Gas
Joined: Aug 2006
Posts: 1,249
Likes: 11
From: oklahoma
1st is the kick down rod hooked up if so you can adjust it.2nd you can adjust Modulator Valve.but it will change regular shifts to to make it shift quicker back it out to make it shift higher screw it in.and then theres the governor but you'd have to pull tail housing to change it
Laughing Gas
Joined: Aug 2006
Posts: 1,249
Likes: 11
From: oklahoma
1st is the kick down rod hooked up if so you can adjust it.2nd you can adjust Modulator Valve.but it will change regular shifts to to make it shift quicker back it out to make it shift higher screw it in.and then theres the governor but you'd have to pull tail housing to change it
Moderator
Joined: Jan 2001
Posts: 56,997
Likes: 2,744
From: Virginia
The modulator is not going to help in this case. If you are wide open, you have no vacuum. What happened when you thought it should shift? Didn't the engine keep revving? If you have it floored, it will delay the shift. Is it a case where you were afraid the engine rpms were getting too high?
Laughing Gas
Joined: Aug 2006
Posts: 1,249
Likes: 11
From: oklahoma
so your sayin the motor has no vacuum @wot? it will have some wont be as much but it still has some.ever tryed unhooking you line it will really raise your shift points.as stated in the other post it will change more driving shift points than wot but it will change them to some
Moderator
Joined: Jan 2001
Posts: 56,997
Likes: 2,744
From: Virginia
So you may have an engine problem? Or did it rev too high and the valves started floating? Did you replace the valve springs with higher rated springs when you changed the cam?
If you have vacuum at wot, then your carb is too small, or your aircleaner is too restrictive.
so your sayin the motor has no vacuum @wot? it will have some wont be as much but it still has some.
