Notices
6.4L Power Stroke Diesel Engine fitted to 2008 - 2010 F250, F350 and F450 pickup trucks and F350 + Cab Chassis

Transmission Slip??

Thread Tools
 
Search this Thread
 
Old Apr 1, 2010 | 08:46 AM
  #1  
Chuckthetruck's Avatar
Chuckthetruck
Thread Starter
|
Junior User
Joined: Mar 2007
Posts: 60
Likes: 0
Transmission Slip??

Hey guys,

Has anyone noticed what feels like a tranny slip when hauling or empty? After purchasing my 08 F250 back in nov, i noticed that when I accelerate heavy on the throttle, the transmission shift patterns seem to be somewhat inconsistant. I took the truck to be serviced by ford shortly after my purchase and the mechanic said what i am feeling is the electronics for the traction control. Now i know these trucks have alot of power but i doubt they have enough power to break the tires loose on drive pavement at 50+ mphs. What concerns me is earlier this morning i am merging on to the highway and I feel this "slip feeling again" To describe in further detail, it feels as if the tranny shifts up a gear and then back down a gear. From what i have noticed, the rpms remain steady and there is no smell or tranny temp issues. Any advice would be greatly appreciated!! Truck is bone stock with 22k on it!

Thanks!

Charles
 
Reply
Old Apr 1, 2010 | 10:15 PM
  #2  
caprang's Avatar
caprang
Posting Guru
Joined: Jan 2006
Posts: 1,513
Likes: 1
These trucks defuel during the shifts to help protect the transmission. I notice that just when it starts to pull decent it almost feels like it backs off, shifts, then gets going again. Its noticable. Is this possibly what you are feeling?
 
Reply
Old Apr 2, 2010 | 09:40 AM
  #3  
senix's Avatar
senix
Super Moderator
15 Year Member
Liked
Loved
Top Answer: 1
Joined: Aug 2008
Posts: 37,384
Likes: 1,868
From: Frederick, MD
Club FTE Gold Member
I agree, you are feeling a bit of de-fueling under the hard pedal. during gentle throttle everything is normal right?
 
Reply
Old Apr 2, 2010 | 09:50 AM
  #4  
Chuckthetruck's Avatar
Chuckthetruck
Thread Starter
|
Junior User
Joined: Mar 2007
Posts: 60
Likes: 0
Thats exactly correct. During normal driving operation the transmission shifts fine. However, when heavy on the throttle i feel this "slip". Ive also noticed the shift pattern when attempting to pass people at an accelerated pace as well. Can you explain to me the defueling operation? Are there any fixes for the defueling or is defueling as per fords design? Thanks for your input guys!!
 
Reply
Old Apr 2, 2010 | 11:15 AM
  #5  
senix's Avatar
senix
Super Moderator
15 Year Member
Liked
Loved
Top Answer: 1
Joined: Aug 2008
Posts: 37,384
Likes: 1,868
From: Frederick, MD
Club FTE Gold Member
The PCM defuels during that heavy throttle to protect the trans. Think of it this way, during heavy loads and heavy throttle there can be max TQ going to that trans.

During shifting with all that TQ It might cause extra wear and slippage on the clutches.

defuel will help to protect and to preserve.

don't know if that is 100% accurate but that is my understanding of the operation.
 
Reply
Old Apr 2, 2010 | 03:10 PM
  #6  
caprang's Avatar
caprang
Posting Guru
Joined: Jan 2006
Posts: 1,513
Likes: 1
Thats my understanding too Senix. The Spartan guys say its much better when tuned but thats because they can also control the TCM to get more line pressure and quicker/firmer shifts.
 
Reply
Old Apr 2, 2010 | 05:08 PM
  #7  
Chuckthetruck's Avatar
Chuckthetruck
Thread Starter
|
Junior User
Joined: Mar 2007
Posts: 60
Likes: 0
thanks guys, makes a lot of sense. I may be crazy but i could swear i notice it more when operating on wet surfaces. Reading the other post, i see that there is alot of controversy concerning tuners, are either of you running tuners?
 
Reply

Trending Topics

Old Apr 2, 2010 | 07:53 PM
  #8  
Mark Kovalsky's Avatar
Mark Kovalsky
Frmr Ford Trans Engr
25 Year Member
Liked
Community Favorite
Top Answer: 3
Joined: Aug 1999
Posts: 24,739
Likes: 2,669
From: SE Florida
Originally Posted by senix
don't know if that is 100% accurate but that is my understanding of the operation.
That IS 100% accurate.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

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

 Verdad Gallardo
story-1

Top 10 Fords at 2026 Carlisle Ford Nationals

 Joe Kucinski
story-2

3 Best / 3 Worst Parts of Modern Ford Ownership

 Brett Foote
story-3

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

 Pouria Savadkouei
story-4

Every 2026 Ford Engine Explained

 Brett Foote
story-5

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-6

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-7

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-8

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-9

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
Old Apr 2, 2010 | 08:48 PM
  #9  
senix's Avatar
senix
Super Moderator
15 Year Member
Liked
Loved
Top Answer: 1
Joined: Aug 2008
Posts: 37,384
Likes: 1,868
From: Frederick, MD
Club FTE Gold Member
Thanks Mark!!

I am running a banks 6-gun. Still have the defueling as the banks is a safe tune that maintains all the emissions.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Wolfpacs
Clutch, Transmission, Differential, Axle & Transfer Case
5
Aug 28, 2012 10:33 PM
scooterspal
1968-Present E-Series Van/Cutaway/Chassis
4
Mar 16, 2012 09:51 AM
bentcipher
1999 - 2016 Super Duty
25
Oct 23, 2010 10:29 PM
darthice
Offroad & 4x4
8
Jan 12, 2010 02:12 PM




All times are GMT -5. The time now is 11:39 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