Limited Slip not working
Thread Starter
|
5th Wheeling
Joined: Feb 2017
Posts: 37
Likes: 1
Limited Slip not working
I just found out that I am not getting positive traction on the rear axle after spinning out of a friends back yard. I recently replaced the rear axle cover and filled it with Mobil 1 gear oil which has the LS additive.I have researched and it seems the LS wearing out is a common issue especially with the miles I have on the truck. Judging by the condition of the rear axle cover it looks like I was the first one to take it off since the factory. My question is should I try adding more LS additive or go forth under the assumption that its just worn out?
Lead Driver
Joined: Apr 2011
Posts: 8,259
Likes: 346
From: Northern California
just curious, what are signs or clues that would indicate the cover has never been removed ?
regardless of the covers history of being removed or not, if the LS clutches are worn out i do not see how adding additional friction modifier would help since its purpose is to let the clutches slip. if they clutch material is worn out then there is not material to grab and they are already slipping.
if the clutches are worn out replacement is required.
you may need to add Fords FL-3 friction modifier to gear oils that say they have some form of LS friction modifier already in them, you will know you need to do this because the LS will chatter without the correct modifier. not adding the correct modifier to your oil will kill your clutches.
regardless of the covers history of being removed or not, if the LS clutches are worn out i do not see how adding additional friction modifier would help since its purpose is to let the clutches slip. if they clutch material is worn out then there is not material to grab and they are already slipping.
if the clutches are worn out replacement is required.
you may need to add Fords FL-3 friction modifier to gear oils that say they have some form of LS friction modifier already in them, you will know you need to do this because the LS will chatter without the correct modifier. not adding the correct modifier to your oil will kill your clutches.
Thread Starter
|
5th Wheeling
Joined: Feb 2017
Posts: 37
Likes: 1
I'm sure the clutches are worn out, just wanted someone elses take on it I guess. As far as the cover I can't say its never been off of course but I am guessing it had not. Sometimes it's obvious that it has due to excess sealant being used/smeared around the sealing surfaces. Orange sealant smeared againt black paint really stands out lol. I actually looked at a 7.3 on a lift at a Ford dealer before I bought this one. It was obvious that the rear end had been gone into since the factory. I mentioned it to the two mechanics there and they said they didn't know of any common rear axle issues on these trucks. Hindsight thats hard to believe they didn't if they were worth their salt but I guess its possible.
Logistics Pro
Joined: May 2017
Posts: 3,523
Likes: 483
From: Southern OH
The factory limited slip doesn't work that well to begin with, and they are usually worn out by 100K. They aren't that hard to rebuild and you can add extra shims to tighten it up so it works better, just don't shim it to tight or you end up with a spool. I rebuilt mine and shimmed it really tight so the tires were skipping around corners it was great for the extra traction but the skipping was hard on the tires, I put a Detroit locker in and it works much better, I get full traction in the rear all the time yet it will still unlock around corners and not skip the tires. The Detroit Truetrac is also a good unit if you want a limited slip.
Banned
Joined: Dec 2018
Posts: 3,541
Likes: 458
The easy and cheap answer is just to live with it. If you plan to keep the truck you're looking at $2500-3000 to have a pro drivetrain shop tear it down and rebuild it from scratch with a Detroit True-trac or locker. Big project obviously and not inexpensive.
Logistics Pro
Joined: May 2017
Posts: 3,523
Likes: 483
From: Southern OH
2500-3000? Lol, a limited slip rebuild kit costs around $250 and is easy to do yourself. A Truetrac with new carrier bearings and shim kit is $800 at most, and if you don't want to do it yourself a shop shouldn't charge more than 3-4 hours of labor.
Trending Topics
Banned
Joined: Dec 2018
Posts: 3,541
Likes: 458
Maybe that's a little high but it depends how deep you wanted to get into it. Mine had to come completely out of the truck to fix the passenger side spindle at the machine shop and the bill was just shy of $1900 to totally rebuild it minus the ring and pinon. Luckily I wasn't on the hook for that one. If it was just a Truetrac and new carriers...1200-1300? If was going to bother taking it apart I would put the good one in there.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
Thread
Thread Starter
Forum
Replies
Last Post
Fuzydog
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
7
Jan 25, 2008 06:55 AM
Red97
Clutch, Transmission, Differential, Axle & Transfer Case
3
Oct 6, 2003 07:03 AM