Notices
1997 - 2003 F150 1997-2003 F150, 1997-1999 F250LD, 7700 & 2004 F150 Heritage
Sponsored by:
Sponsored by: Auxito

Limited Slip Differential

Thread Tools
 
Search this Thread
 
Old Mar 29, 2017 | 06:12 PM
  #1  
Azmorg's Avatar
Azmorg
Thread Starter
|
New User
Joined: Mar 2017
Posts: 4
Likes: 0
Limited Slip Differential

I have a 2003 F150 SuperCrew 4X4. It's got street tires.
The ID plate says it has a limited slip differential (B6).
Yet I have never been able to get both rear tires to break loose.
Only the right rear will spin; even when its wet out.
I've also owned a Silverado & a Ram. Both of those would smoke the tires no problem. So how come my F150 is such a whimp?
 
Reply
Old Mar 29, 2017 | 06:25 PM
  #2  
steve(ill)'s Avatar
steve(ill)
Hotshot
20 Year Member
Joined: Jul 2005
Posts: 11,932
Likes: 181
it could be worn out, or need adjustment. It could be "pulling", but not at same speed as the other tire. Jack up the back end, turn one tire and see what the other is doing. You could pull rear cover, change oil, and inspect inside / clutch plate clearances.
 
Reply
Old Mar 29, 2017 | 08:42 PM
  #3  
Azmorg's Avatar
Azmorg
Thread Starter
|
New User
Joined: Mar 2017
Posts: 4
Likes: 0
Originally Posted by steve(ill)
it could be worn out, or need adjustment. It could be "pulling", but not at same speed as the other tire. Jack up the back end, turn one tire and see what the other is doing. You could pull rear cover, change oil, and inspect inside / clutch plate clearances.
Thank you for the reply.
If I jack up the back end and spin a tire, the other should turn as well, just in the opposite direction, right? And if so, then that would confirm it's limited slip?
 
Reply
Old Mar 29, 2017 | 09:18 PM
  #4  
steve(ill)'s Avatar
steve(ill)
Hotshot
20 Year Member
Joined: Jul 2005
Posts: 11,932
Likes: 181
no, if you have an OPEN rear end, the opposite tire will spin backward because the transmission is in park and driveshaft can not move..... if you have an LS unit, the tires should be locked together... since the drive shaft can not move, BOTH tires should be locked and will not rotate.
 
Reply
Old Mar 30, 2017 | 08:44 AM
  #5  
Azmorg's Avatar
Azmorg
Thread Starter
|
New User
Joined: Mar 2017
Posts: 4
Likes: 0
Got it.
Thank you.
 
Reply
Old Mar 30, 2017 | 06:22 PM
  #6  
stevenn1's Avatar
stevenn1
Senior User
Joined: Sep 2003
Posts: 411
Likes: 2
From: KS
Probably because their is too much amount of XL-3 FRICTION MODIFIER mixed in with the diff lube.
 
Reply
Old Mar 31, 2017 | 10:41 PM
  #7  
Bluegrass 7's Avatar
Bluegrass 7
Lead Driver
15 Year Member
Joined: Sep 2006
Posts: 7,907
Likes: 143
There is another way to test the relative lockup friction of the internal discs for wear.
Set up a test rotation of one wheel with the other on the ground.
Use a Torque wrench and socket on a lug nut.
Test the torque point required to cause the internal disc pack to slip.
It should be something over 40 pound feet on each wheel one side at a time.
Good luck.
 
Reply
Old Apr 1, 2017 | 09:13 AM
  #8  
Azmorg's Avatar
Azmorg
Thread Starter
|
New User
Joined: Mar 2017
Posts: 4
Likes: 0
So, you would apply the torque to the tire that's in the air, and anything under 40 lb ft would indicate discs are worn?
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

10 Ways Ford is LOSING to the Competition

 Joe Kucinski
story-1

Top 6 Best Deals Available on New Fords & Lincolns Right Now

 Brett Foote
story-2

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

 Verdad Gallardo
story-3

Top 10 Fords at 2026 Carlisle Ford Nationals

 Joe Kucinski
story-4

3 Best / 3 Worst Parts of Modern Ford Ownership

 Brett Foote
story-5

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

 Pouria Savadkouei
story-6

Every 2026 Ford Engine Explained

 Brett Foote
story-7

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-8

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-9

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

 Verdad Gallardo
Old Apr 1, 2017 | 10:24 PM
  #9  
Bluegrass 7's Avatar
Bluegrass 7
Lead Driver
15 Year Member
Joined: Sep 2006
Posts: 7,907
Likes: 143
Yes.
It is a standard way to check the disc clutch operation.
The difference between a passenger car test and a truck test is the truck S spring tension is greater than a passenger car rear.
The slip point depends in the disc stackup wear thickness and surface condition, the spring tension and the fluid/ slip condition.
Good luck.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
imq707s
1999 - 2016 Super Duty
9
Dec 19, 2018 09:28 AM
caseydudem
1994.5 - 1997 7.3L Power Stroke Diesel
8
May 13, 2007 07:09 PM
dynamis5
2004 - 2008 F150
17
Apr 2, 2007 09:25 AM
260falcon
Clutch, Transmission, Differential, Axle & Transfer Case
7
Jan 29, 2006 12:02 PM
SC98Lariat
1997 - 2003 F150
6
Jan 8, 2002 07:05 AM




All times are GMT -5. The time now is 06:02 AM.

story-0
10 Ways Ford is LOSING to the Competition

Slideshow: 10 ways Ford is losing to the competition

By Joe Kucinski | 2026-06-15 09:52:01


VIEW MORE
story-1
Top 6 Best Deals Available on New Fords & Lincolns Right Now

Some great targets in today's expensive world.

By Brett Foote | 2026-06-15 09:35:19


VIEW MORE
story-2
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-3
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-4
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-5
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-6
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-7
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-8
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-9
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