What does electronic differential less limited slip even mean? Do I add a friction modifier?

 

Do you have an electric locking diff? If so no friction modifier required.
If you have a limited slip then it is required.
You can't have both.

 

That is how it was described on the window sticker. I bought it brand new so the sticker came from Ford versus some car lots idea of what it might be.

 

limit slip means there is a clutch that SLIPs between the left and right sides of the axle.. it needs FRICTION MODIFIER in the oil to make it worn.

ELECTRONIC LOCK, means there is a solenoid that drops a pin in a hole and LOCKS the left and right side together.. There is ZERO SLIP. They should call it Electronic Lock Up, without reference to Limit Slip.

I dont know what year truck you have... There should be a **** you ROTATE on the dash that goes from 2 wheel drive to AUTO 4 wheel drive to LOW 4 x 4 to HIGH 4 x 4 ( maybe you dont have AUTO).... If you have ELECTRONIC, you can PULL THE **** OUT 1/4 inch and it will ENGAGE the rear Electronic Lock Axle.

 

I have an STX special addition with a 5 4 Triton motor and its 2wd and its a 9.75. Its a one off because it was on its way to being a 4wd truck when the crash came. My truck was assembled 4/30/07 so over the years I've found that some parts are for 4wd and others for 2wd. The window sticker from Ford says its an electronic less limited slip 3:31 rear end, thats all it says. There are no buttons or ***** to pull nor did I see anything in the diff. I just pulled the axles out to replace the wheel berrings and you have 2 axle gears and 2 spider gears and the big running gear I think its called. Another problem is now the spider gears fell out and I can't get them back in with the spacers on the back of them.

 

A limited slip axle has clutch packs behind the side spider gears and this version requires friction modifier in the diff oil.

 

If you look at the topic "spider gears fell out", (right above yours at the moment) it shows what seems to be a handy trick to get the spiders back in.

 

You didn’t say what year vehicle, but at some point Ford’s Limited slip differential didn’t use friction discs to limit the slip, but just used the ABS to stop which ever axle shaft was spinning excessively. I suspect the window sticker is just trying to indicate that you have a locker with no limited slip control when not electronically locked.

 

my apologies indid forget the year with all the frustration. It's a 2007 and it was assembled 4/30/07 in the Kentucky plant. My spider gears came out and lets just say it was an adventure getting them back in. My VIN says its an electronic and I don't have any buttons to push and I didn't see anything special in the diff. There was (you'll have to forgive me if I don't know what everything is called) the gear against the back wall connected to the driveshaft , the large vertical pinion gear i think its called and 2 axle gears and 2 spider gears with a large rod running between them. The statement "electronic less limited slip" makes no sense to me but I want to be sure I don't need a modifier along with the 75w-140 or just add it incase unless it hurts it.

 

the rear gear on the drive shaft is the PINION.. The BIG gear is the RING or BULL gear.. The small gears are SPIDERS... if you have NO WIRES going to an internal solenoid / pin arrangement, then you DO NOT have ELECTRIC LOCK.. If you dont see a STEEL CAGE inside the differential with clutch plates in it, then you DONT HAVE LIMIT SLIP either... Sounds like a standard rear axle............ look at the CODE on the door post under "axle".