View Full Version : how to add gear oil? anyone

05-07-2004, 03:07 AM
hey i want to replace the gear oil in the differential. The problem is these husings dont have a drain plug. how can i take out the oil and put some back in? my friend says to get a lil baggie that can be easily ripped up and fill it up with gear oil and put it in and basically when the gears start going it will ripp the baggie and shred it with no harm. I dont know about that. anyone?

05-07-2004, 05:25 AM
The baggy thing doesnt sound like a very hot idea imo.

Actually, I believe there is a fill plug near the top, backside of the diff. as I believe I spotted it a while ago when I was working on something else, allthough I could be wrong since I have not yet done this particular job myself.

There are two ways to drain it, you can pull the back cover, or get a hand pump, to pump the fluid out from the top. In order to fill it you will need a squirt top botttle.

Also an important note, I believe our Differentials require a friction modifier, someone please correct me if I am wrong.

05-07-2004, 10:23 AM
You are right. Go to ford and get a 8 ounce bottle of friction modifier. Just pull the cover off with a oil drain pan under it. There is only one draw back to this. The gear lube with the friction modifier STINKS TO HIGH HEAVEN! Just dont get any on you or you wont be getting any dates too soon. Oh here`s one. Let say you know some one that screwed you over royal well a drop of friction modifier inside the car will stink for years. Just make sure you dont get caught. :D :D :D

05-07-2004, 12:30 PM
friction modifier? sounds expensive if getting it from ford. maybe GM will have it also?

05-07-2004, 02:01 PM
$3.39 Trust me its cheap at the ford dealer

Joisey Jim
05-07-2004, 02:25 PM
If you don't want to have to unbolt the diff. hanger (place a jack under the housing) and, then remove all the bolts & the cover (also need black RTV to make a gasket when reassembling); then get a cheap oil suction pump (like a big diameter bicycle pump) and suck out the old oil. To put new oil in there are similar little plastic pumps that mount into the top of the oil bottle. Both are available at places like PepBoys. Also you only need the friction mod. if you have a limited slip diff (traction loc unit). Not all models came with this, except 5 speeds. I believe you only need 4 ozs of friction mod. + 3 pints of 75w90 oil.

05-07-2004, 02:59 PM
wait, i thought all SC's came with limited slip differential. I thought only the late model SC's came with the traction control crap. Well i am really confused now. Well anyways. Im thinking of getting this nice differential cover from TRICK FLOW. Well also, what kind of gear oil, there are so many weights of it, i dont know which one it is.

05-07-2004, 03:13 PM
ALL 89-93 supercoupes came with traction lock differentials. It was only the 94/5 sc's where only the 5-speeds had it. ;)

Joisey Jim
05-10-2004, 12:59 PM
You'd better check any aftermarket diff. covers, because although they are standard Ford 8.8, ours have a support bracket on the cover due to the independent suspension. So as far as I know only the SC, Mark 8 and late model Cobra share this cover. As for oil it's 3 pints of 75w90 gear oil + 4 ozs of friction mod.