Slipping LSD

[Broosedamoose]

My truck originally came with an open differential with 3:73’s. I took the LSD from my totaled truck (03 FX4 Off-Road) and put it in this truck (07 XLT). My old truck never spun going around corners in the rain and would kick the ass end out if I have it some throttle. It would always light up both tires also. After swapping the differential, my truck still spins on one side going around corners and will mostly only light up the passenger side tire! Sometimes both tires will spin though. I was told the S spring is probably weak and to replace it with one for an F150. Will this work or is the spring the same in both trucks?

 

[19Walt93]

If you have a clutch type limited slip, it's possible the friction plates are worn and need to be replaced.

 

[superj]

when i started reading this, it immediately brought to mind when my wife had an lsd in her bmw.

she left a parking lot that had some gravel on the road from a truck spill and she did a 360. she came home and wanted the car sold, ha ha ha. i just pulled the lsd form her car and put it in my 325i and gave her the open diff.

you were slipping but not how she did, ha ha ha

 

[Broosedamoose]

I looked for a new clutch pack but there are so many different ones! They range from around $50 to over $300! I took the open differential out and had the LSD from an 03 installed. I searched for 2003 Ford Ranger Rear Differential clutch pack. I checked out the Tech Article and it list part# M-4700-C. Is this correct?

 

[BroncLander]

When you did the swap did you change the fluid and not use any additive?

If not, now is the time to drain it out and add the correct proportions of both dif oil and limited slip additive. Or the clutches will slip (if it's a clutch type) I'm only familiar with my Jeep LSD. So I could be talking out my butt here.

 

[Broosedamoose]

It was done by my mechanic so I'm sure he put in the additive. I hoped to get some feedback about the part number but I guess I'll just roll the dice and order it. The tech article must be right or they would have not posted it.

 

[pjtoledo]

I looked for a new clutch pack but there are so many different ones! They range from around $50 to over $300! I took the open differential out and had the LSD from an 03 installed. I searched for 2003 Ford Ranger Rear Differential clutch pack. I checked out the Tech Article and it list part# M-4700-C. Is this correct?

that's a 31 spline kit.
fine for Explorers but only a select few rangers had 31 splines.
the big S spring is the difference between 28 & 31 spline kits.


8.8" TRACTION-LOK REBUILD KIT WITH CARBON DISCS| Part Details for M-4700-C | Ford Performance Parts

 

[Broosedamoose]

that's a 31 spline kit.
fine for Explorers but only a select few rangers had 31 splines.
the big S spring is the difference between 28 & 31 spline kits.


8.8" TRACTION-LOK REBUILD KIT WITH CARBON DISCS| Part Details for M-4700-C | Ford Performance Parts

Yes but the discs are the same. I was not going to use the S-Spring that comes with the kit. I bought a new one for a 28 spline. In the description in your link it says the 28 spline S-Spring is not included.

 

[BroncLander]

It was done by my mechanic so I'm sure he put in the additive. I hoped to get some feedback about the part number but I guess I'll just roll the dice and order it. The tech article must be right or they would have not posted it.

Might be worth asking him what he put in it. Without mentioning it's a limited slip just ask what he used in it? You would definitely think he did, but if not, it's a really easy fix now that could prevent damage

 

[19Walt93]

Might be worth asking him what he put in it. Without mentioning it's a limited slip just ask what he used in it? You would definitely think he did, but if not, it's a really easy fix now that could prevent damage

If he didn't use friction modifier the clutches wouldn't slip, they'd chatter particularly on low speed turns.

 

[alwaysFlOoReD]

^^^ this. It's what my truck is doing.

 

[bobbywalter]

Yes...modifier is to keep them from wearing out too fast.

They have approximately a 20 k mile service life for best performance....unless you take them off road with large tires or have a low tire...then you wipe them out pretty quick.

They are garbage for heavy 4x4 activity.

A tru trac or torsen is worth the effort.

I have blown way too many spiders and side gears through diff covers packing them to get them to work sort of....back in the 80s and 90s because it was cheap and easy....

Since yours appeared to last so long .. might be worth rebuilding.


Tru trac with that supercharger is a wise investment I would wager.

 

[19Walt93]

Friction modifier is used to prevent clutch chatter, not wear.
"I have blown way too many spiders and side gears through diff covers packing them to get them to work sort of....back in the 80s and 90s because it was cheap and easy...." It sounds like you were a GM guy in the past.

 

[bobbywalter]

Friction modifier is used to prevent clutch chatter, not wear.
"I have blown way too many spiders and side gears through diff covers packing them to get them to work sort of....back in the 80s and 90s because it was cheap and easy...." It sounds like you were a GM guy in the past.

Well....I ran a lot of 7.5 diffs initially....so may as well have been a Chevy..

chatter is wear. Bite slip bite slip....Friction modifier is slime. No friction modifier and the clutches wear much faster.

Clutch limited slips only work good on dry flat ground. Going straight. If you follow those guidelines they will last forever.

 

[00t444e]

Those track lock limited slips are junk that don't work that well, always have been, worst limited slip there is. Clutches are worn out for sure, but even when brand new they don't work that well. You would have been better off putting a lock right locker in your open carrier, get a Detroit Truetrac if you want a good limited slip.