Got a problem...

Tally_4.6

Member
Feb 26, 2006
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17
Orlando
Well i changed my rear diff. fluid about 2 weeks ago. Then i started to noticed the car vibrating alot when above 50-55 mph. Me being the idiot that i am i didn't know my car had limited slip (please dont flame), therefore i did not use any friction modifier.:nonono: So there is only new 80-90w gear oil in there now. My question is can i just take some of the fluid out and out in the friction modifier or is my rear end ****ed?:bang:

Please help.I'm so stupid.
 
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Just drain the fluid, and refill it with the friction modifier. You probably lost use of the trac-loc, but assuming you don't put a ton of miles on it in 2 weeks, you'll probably get it back when you refill it.
 
Right, but most 80w90's you find in the store aren't full synthetic, they are synthetic blend. Unless you used RP, Mobil 1, etc, then it probably doesn't already contain the stuff you need.
 
sgarlic said:
Just drain the fluid, and refill it with the friction modifier. You probably lost use of the trac-loc, but assuming you don't put a ton of miles on it in 2 weeks, you'll probably get it back when you refill it.

If i do that should the vibration go away, or has the damage been done.
 
the98stang said:
naw you'll be fine dude. just put some synthetic mobil1 70w-140 in there and call it a day. no friction mod :)
I think i'll just use the sucker machine at work to take out most of the fluid and add the friction modifier, then fill it up with 80-90w again. Thanks for the help bro, i was afraid i really screwed something up, hopefully it will go away.

Since ill be getting some friction modifier...what would be best?
The stuff at advance auto parts... or the ford friction modifier?
 
Tally_4.6 said:
I think i'll just use the sucker machine at work to take out most of the fluid and add the friction modifier, then fill it up with 80-90w again. Thanks for the help bro, i was afraid i really screwed something up, hopefully it will go away.

Since ill be getting some friction modifier...what would be best?
The stuff at advance auto parts... or the ford friction modifier?

Ford :)
 
the98stang said:
The mechanic that did my gears said friction modifier does not have to be added if synthetic oil is being used. I'm not sure if that's true or not...


199.999 percent WRONG... even synth fluid needs friction modifier. the modifier loosens up the limited slip action so you can go around corners without chattering.. But some fluids come with modifier maybe thats what he was talking about, but not regular synth.

if you have no modifier in and you can do a tight. I mean wheel all the way over tight turn at crawl speeds without binding up or chattering then your limited slip is blown and inop.
 
svttech76 said:
if you have no modifier in and you can do a tight. I mean wheel all the way over tight turn at crawl speeds without binding up or chattering then your limited slip is blown and inop.
What does chattering sound like?...The vibration only occurs in 4th and 5th gear above 50-55mph, not at low speeds.
 
svttech76 said:
199.999 percent WRONG... even synth fluid needs friction modifier. the modifier loosens up the limited slip action so you can go around corners without chattering.. But some fluids come with modifier maybe thats what he was talking about, but not regular synth.

if you have no modifier in and you can do a tight. I mean wheel all the way over tight turn at crawl speeds without binding up or chattering then your limited slip is blown and inop.

Well I'm running mobil1 synthetic....does that have the friction mod in it?
 
the98stang said:
If the friction mod is such a big deal, why doesn't the owner's manual mention it?


ok do you want it out of the ford service manual.


2000 ford service manual said:
General Specifications Item Specification
Lubes and Sealers
SAE 75W-140 High Performance Rear Axle Lubricant
F1TZ-19580-B WSL-M2C192-A
Premium Long-Life Grease XG-1-C ESA-M1C75-B
Rust Penetrant and Inhibitor F2AZ-19A501-A ESR-M99C56-A
High Temperature Nickel Anti-Sieze Lubricant F6AZ-9L494-AA ESE-M124A-A
Additive Friction Modifier C8AZ-19B546-A EST-M2C118-A
Clear Silicone Rubber D6AZ-19562-AA ESB-M4G92-A
Threadlock and Sealer EOAZ-19554-AA WSK-M2G351-A5
Lubricant Fill Level Checks
Additive Friction Modifier 118 ml (4 oz)
Approximate axle fill capacitya b 1.66-1.77-liters (3.5-3.75-pints)
6.4-14.3-mm (1/4-9/16-in) below the bottom of the fill hole
Clearance, Tolerance and Adjustments
Maximum ring gear back face runout 0.102 mm (0.004 in)
Maximum differential case runout 0.076 mm (0.003 in)
Differential side gear thrust washer thickness 0.762 mm - 0.813 mm (0.030 in - 0.032 in)
Differential pinion gear thrust washer thickness 0.762 mm -0.813 mm (0.030 in - 0.032 in)
Maximum axle shaft end play 0.762 mm (0.030 in)
Ring gear backlash 0.203-0.304 mm (0.008-0.012 in)
Variation between teeth maximum backlash 0.102 mm (0.004 in)
Pinion flange runout 0.25 mm (0.010 in) T.I.R.

a If it is necessary to refill a Traction-Lok® axle with new lubricant, add 118 ml (4 oz) of Additive Friction Modifier C8AZ-19B546-A or equivalent meeting Ford specification EST-M2C118-A before filling the axle with the new lubricant.
b In-vehicle repair refill capacities are determined by filling the rear axle with the specified lubricant to 6.4-14.3-mm (1/4-9/16-in) below the bottom of the fill hole.


read the bottom of this specifications list for a 2000 model year mustang 8.8 traction-lok rear end..
If it is necessary to refill a Traction-Lok® axle with new lubricant, add 118 ml (4 oz) of Additive Friction Modifier C8AZ-19B546-A or equivalent meeting Ford specification EST-M2C118-A before filling the axle with the new lubricant.
b In-vehicle repair refill capacities are determined by filling the rear axle with the specified lubricant to 6.4-14.3-mm (1/4-9/16-in) below the bottom of the fill hole

heres one more.


FORD! the people that built the damm car said:
SECTION 205-02B: Rear Drive Axle/Differential — Ford 8.8-Inch Ring Gear 2000 Mustang Workshop Manual
IN-VEHICLE REPAIR Procedure revision date: 06/17/1999

--------------------------------------------------------------------------------

Differential Housing Cover
Removal

Raise and support the vehicle. For additional information, refer to Section 100-02.
NOTE: Empty the lubricant into a clean container for reuse.

Remove the differential housing cover (4033).
Remove the 10 bolts and drain the lubricant from the differential housing (4010).
Remove the differential housing cover.

Installation

CAUTION: Make sure the machined surfaces on both the differential housing and the differential housing cover are clean and free of oil before applying the new silicone sealant. To prevent contamination, cover the inside of the rear axle (4001) prior to cleaning the machined surface.

Clean the differential housing and the differential housing cover gasket mating surfaces.
CAUTION: Install the differential housing cover within 15 minutes of applying the silicone, or it will be necessary to remove and reapply new sealant.

Apply a continuous bead of sealant of the specified thickness to the differential housing cover.
Use Clear Silicone Rubber D6AZ-19562-AA or equivalent meeting Ford specifications ESB-M4G92-A.

NOTE: If possible, allow one hour before filling the axle with lubricant to make sure the silicone sealant has cured.

Install the differential housing cover.
Install the differential housing cover.
Install the 10 bolts.

NOTE: If it is necessary to refill a Traction-Lok® axle with new lubricant, add 118 ml (4 oz) of Additive Friction Modifier C8AZ-19B546-A or equivalent meeting Ford specification EST-M2C118-A before filling the axle with the new lubricant.

NOTE: In-vehicle repair refill capacities are determined by filling the rear axle with the specified lubricant to 6.4-14.3-mm (1/4-9/16-in) below the bottom of the fill hole.

Fill the rear axle to the level shown, approximately 1.66-1.77-liters (3.5-3.75-pints) of lubricant, and install the filler plug.
Use SAE 75W-140 High Performance Rear Axle Lubricant F1TZ-19580-B or equivalent meeting Ford specification WSL-M2C192-A.

Lower the vehicle.




Now not only have I said it needs friction modifier even in 75/140 lube that IS a synth fluid. but ford has said it too.

Please next time just take my word for it. I hate wasting the time to copy and paste this stuff.
 
svttech76 said:
ok do you want it out of the ford service manual.





read the bottom of this specifications list for a 2000 model year mustang 8.8 traction-lok rear end..


heres one more.









Now not only have I said it needs friction modifier even in 75/140 lube that IS a synth fluid. but ford has said it too.

Please next time just take my word for it. I hate wasting the time to copy and paste this stuff.

no need to get cranky now. but you would think that Ford would have put that in the owner's manual because it's important. Now I know :)