diff fluid change for a friend

[RiPPiNiTuP7]

my buddy is bringing his 2000 explorer over to have me fix his rear diff. the cover is leaking so it should be a quick no brainer fix, but i did have a couple questions since i have to yank the cover off. he has 45k on it and this is the first fluid change. it has the stock limited slip, so should i run the 75w-140 or is there something better recommended? and is synthetic suggested? what friction modifier and amount? lastly, on a normal street driven how long do the clutches in the diff typically last?

thanks in advance.

edit: also what is the capacity of the diff?

 

[410Fortune]

the stock LS will start wearing at about 60K but some still grip at 150K so you never know.

The 8.8 cover is normally sealed with just silicoln, but on my BII rear it wouldn't seal up, so I got a gasket from Car Quest and it has not leaked since.

2000 asks for synthetic gear lube, but its the same 8.8 Ford has been building for a long time, I run 80W cheapo fluid with the friction modifier (reduces foaming). I change my diff fluid often so I can no longer justify the $$$ for full synth, if you dont plan to change it often then by all means, I prefer Mobil synth gear lube

While you are in there check the vent line for blockage, compressed air will make short work of this.

 

[IZwack]

and is synthetic suggested? what friction modifier and amount?

if you decide to go with synthetic, most if not all synthetics already come with friction modifier -- just read the bottle.

 

[MountaineerGreen]

My LS worked great when I pulled it a 125K, but it hadn't been used offroad much.

If he isn't going to service it much, I'd go full syn. Cost a little more, but worth it IMO. I run it in mine, don't get in water if I can help it, so I don't have to worry about changing it often.

I drained and refilled my 8.8 yesterday- it took 3.75 quarts to fill it to the plug.