Notices
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks Discuss the Early Eighties Bullnose Ford Truck

C6 downshifting????

Thread Tools
 
Search this Thread
 
Old Oct 20, 2016 | 09:20 PM
  #1  
william16339's Avatar
william16339
Thread Starter
|
Senior User
Joined: Jul 2014
Posts: 246
Likes: 0
C6 downshifting????

hey guys I have a 84 f250 351w c6. I don't know what's done to the c6 but shifts very good. I'm thinking it has a shift kit. Because it shifts hard into second and is very firm. I have an adjustable vaccine modulator on it. And I have it turned in a couple turns. Just wondering I have no kick down. .... Going up a hill it still kicks down to second. How?
 
Reply
Old Oct 21, 2016 | 05:44 AM
  #2  
FuzzFace2's Avatar
FuzzFace2
FTE Legend
10 Year Member
Photogenic
Community Builder
Liked
Joined: Nov 2015
Posts: 30,940
Likes: 4,125
From: Angier, NC
Club FTE Gold Member
It uses the vacuum modulator for that.
Dave - - - -
 
Reply
Old Oct 21, 2016 | 05:51 AM
  #3  
Franklin2's Avatar
Franklin2
Moderator
25 Year Member
Photogenic
Community Builder
Community Influencer
Joined: Jan 2001
Posts: 56,997
Likes: 2,743
From: Virginia
Club FTE Gold Member
+ the governor in the trans. Modulator tells it the load, governor tells it the road speed.
 
Reply
Old Oct 21, 2016 | 10:17 AM
  #4  
Braggs's Avatar
Braggs
Senior User
Joined: May 2016
Posts: 477
Likes: 3
My pickup (C6) runs in 2nd gear from 10mph to about 45 max under full throttle. Don't forget these pickups weren't designed to go much over 55 mph because the law at the time didn't allow it. That's why the gearing is so low. I can hardly ever get my pickup to kick down to 1st gear. It likes to ride in 2nd most of the time since I normally only drive it around town. Over 30mph will shift to 3rd if I don't have it floored.

If you wanted to know how it works, the vacuum modulator hooks up to the engine vacuum system. There's a certain amount of vacuum required to suck back the diaphragm/pin (usually minimum of 14 psi of vacuum). When the engine vacuum pressure drops due to acceleration (air from carb being open filling the vacuum void), the pin is pushed forward which pushes the throttle valve open.




The way the governor works is pretty slick too. It has a couple "valves" springs pushing them closed too. This one, though, is attached to the output shaft which spins when the vehicle is moving. As it spins, the centrifugal force pushes the valves outwards compressing the spring and opening the valve so that fluid can flow through.



Hope this helps someone understand how the C6 transmission functions better.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
nothercrash
1973 - 1979 F-100 & Larger F-Series Trucks
12
Mar 5, 2024 07:51 PM
_Trekker
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
15
Jul 20, 2019 06:59 AM
Chris Ko
Clutch, Transmission, Differential, Axle & Transfer Case
4
May 13, 2017 10:23 PM
79sparky
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
7
Feb 20, 2013 02:10 PM
JoeF150
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
3
Feb 27, 2003 02:56 PM




All times are GMT -5. The time now is 05:04 PM.

story-0
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level

Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.

By Verdad Gallardo | 2026-06-12 11:01:55


VIEW MORE
story-1
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-2
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-3
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-4
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-5
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-6
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-7
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-8
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-9
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE