Gear Oil.
 

Ok, I think I've pretty much got everything figured out, but wanted to run it by you guys real quick.

Time for 20 questions! :D

So, the stock diff. uses about 2 quarts of 75w90 + the friction modifier, right? Obviously my car has FRPP 3.73's, still the same?

To drain do you recommend taking off the diff. cover? If you take the diff. cover off, I assume it would be good to replace the gasket at the same time?

Now, last but definitely not least. I'm looking at using Amsoil "Severe Gear" synthetic oil. http://www.amsoil.com/storefront/svg.aspx and their friction modifier. http://www.amsoil.com/storefront/ada.aspx



So to summarize, this is what I'll need to change the gear oil: **Updated**

• 3 qts 75w90 Gear oil.
• 4 oz friction modifier.
• Black High-temp RTV Sealant.
• May need pinion gasket.

Thanks!! :)

i just used royal purple max gear oil...the stuff already has friction modifier in it. there is no gasket only RTV. pick up some black high temp RTV. the differential is what determines what gear oil you would use because its a LSD unit.

I just added oil till it came pouring out a lil over 2 quarts. i love how you have to buy 3! when i did my gear oil i also had to replace my pinion seal so make sure you get a good luck at that thing while your under the car. i would check before you even do this just so you dont have to make 2 trips.

How much of a PITA was it to change the pinion seal? I'd like to do all of this myself (really don't want to take it to delk), but don't want to get in over my head.

Also, everything that I read about RP, people said they still added the modifier?..

more modifier wouldnt hurt but its already in there so its like adding sugar to sweet tea.

pinion seal is easy just lock up the E-brake drop the driveshaft loosen the pinion nut pop out old gasket and re-torque the pinion nut to a tune of 110-120 FT LBS...i think its that setting not sure its been over a year. i didnt have air tools when i did this i just used a cheater bar to break that bitch loose.

remember, you may not even have to change it. Just look at your differential and if you see residual fluid at the pinion than you know its leaking and is time to change it. i ruined mine running my car to 170 MPH...my rear main seal is leaking still!

I hope you don't mean that you filled it until it came out the fill hole, because the manual specifically states that the level should be below that (I want to say 9/16").

As for the procedure, you need to remove the cover, unless you have one w/ a drain plug. While you can use a gasket to reseal everything, Ford used RTV, so the black (oil resistant stuff) should be fine. Personally though, I think Amsoil is crap. I've used their 2-stroke stuff and it was garbage. Redline 75W-140 is what I use, and it has friction modifier in it already.

Why do you use 75w140?

I'm a firm believer in Amsoil, we've used it in my dad's Dodge ram for over 200,000 miles and changed the oil in it 7 times.. That's something like 29-30,000 miles between oil changes and it runs like it's brand new.

so looks like my shit is over serviced, LOL.

LOL! It does have the dual filter system on it, but when you think about it, changing the engine oil once every year or two vs. changing it every 3-5,000 miles is totally worth it..

Doesn't it need to be changed only like every 100k? lol.

Are you talking about the Gear oil?

If you're talking about the gear oil I'm just changing it to make myself feel better, plus it pops a little bit while cornering and Modular PowerHouse said that it probably just needed to be serviced. Plus, the car is 8 years old.. Gears have been in for IDK, 10-15k miles and I have no idea if Dave ever changed the fluid after they "broke in."

I have nothing productive to add to this thread other than that the title should read "Gear Oil... smells like rotten ass."

To each his own. I had bad experiences w/ Amsoil and Redline was always good to me. Back in my moped days, switching from Amsoil to Redline actually gave me a noticeable increase in power, while also reducing smoke (meaning cleaner combustion).

As for the grade, that's what my manual said. I know the earlier cars had 80W-90 as the requirement while the latter ones had the thinner stuff. It's your call though. 75W-140 will probably suffice (and yield better mileage) but if you think you are going to do a lot of shock loading, stick w/ 80W-90.

I just went with the 75w90 Amsoil and the friction modifier. I trust Amsoil, never had one ounce of trouble from it in the past.

Not five minutes ago I was replacing my diff. cover, got online to look up the torque specs (it's 32ft-lbs.). Everything looks good.

So I changed my gear oil yesterday. Everything went smoothly, got the diff cover off, cleaned it really well and inspected the gears. Everything looked good, no shavings in the fluid, rotated the assembly and it rolled smoothly. Sat a good bead of black RTV on the cover and bolted it back in place, torqued the bolts back to 32'lbs + just a little tug for good measure. Searched around and finally found the filler, filled it back up (after letting the RTV sit for at least 30 min). I filled it until the oil just barely started to come out of the filler and let it drain off for a minute then plugged it back up.

Let it sit for a good hour or so and everything looks good. Drove it back to my house and let it sit again for about 3-4 hours. Took the car out last night and drove like a granny, then came home and let it sit overnight until probably 5 this afternoon then just drove around for about 20 minutes, came back home and there was a small amount of oil on the bottom of the diff.

I'm wondering if maybe I over filled it (used a little over 2 qts + the friction modifier) and it is coming out of some kind of a relief valve or something? Is there any such thing? I sat an oil pan underneath the car and checked it at about 7:30 this afternoon and there wasn't anything in it, so if it's leaking or puking fluid it must be while I'm driving.. The RTV on the diff. cover sems to be cured well and there aren't any gaps or anything so this makes no sense.

Any ideas?

never used Amsoil, but since you do not need to change the oil in your differential very often I would spend the extra penny and yes do the gasket.. why not while the damn thing is pulled apart.

bump. :rolleyes:

:)

There is a vent valve, but fluid wouldn't come out there since it's on the axle tube. Generally too much fluid will result in it coming out the pinion seal.

yeah, the last time the diff was opened was when modular powerhouse did the gears..

The vent is on the axle tube. It wont come out of that unless you overfill the shit out of it. A little over 2 qts isn't overfull. I'd clean everything really well(maybe spray with brake cleaner) so the diff is dry. Then take for a drive, then park it and inspect to see where the fluid is coming from. probably the pinion seal like bassman said.

you must of had some fluid that was still on the diff after you let the excess drain out of the fill hole.

If thats not the case than your pinion seal is leaking.

Wouldn't the pinion seal leak constantly though? For instance, if the car is sitting overnight, I should see some residual fluid dripping/leaking. Right?

IF it is leaking, it seems to only be doing it while the car is moving.

The pinion seal will really only leak while the car is moving. You will be able to tell that it's that if you notice a concentration of fluid at the pinion.

the way i knew my pinion seal was leaking was from wiping it clean after driving and checking the pinion again after another short drive. mine leaked to the point where it would leave a 3" diameter stain on the street!

when i changed the pinion seal and fluid i noticed that i still had a leak and did the same as above. pinion seal was good to go and when i ran my fingers on the diff around the fill plug i felt some residual fluid that was still sitting from my over fill job.

Damn.. It's been raining all day again so I haven't been able to check it. Just drove the Stratus today for good measure. I guess the best thing to do would be to clean it all off good with some brake parts cleaner to make sure all of the overfill was gone. I guess the best thing to do after that would be to get the car on jack stands and just get it in gear and see if it leaks..

If it is the pinion seal, I'm not sure if I can replace that myself.. I know very little about diff's.. So Unless someone has a good write-up on it or something I'll have to take it to Gateway or 2 rivers ford. :(

pinion seal is the easiest seal to replace on a diff IMO... other than the cover gasket.

Any tips/ how to's? Maybe you can print me something from the stealership? :)

remove the driveshaft...well shit...thats an input shaft seal perhaps Im thinking of... are you talking about the seal at the driveshaft input into the rear end?

I wish I knew.. If I did I wouldn't be asking! lol <- that was a joke.

Honestly, I have no clue.. I just looked it up on Autozone's website and it seems like a fairly complex install, then again their "how-to's" have never been known to be incredibly in-depth so who knows. I guess I should probably pick up a Haynes/Chilton's manual and read a little bit about it.

At this point, I don't even know if it's really leaking or if maybe some of the excess fluid just got trapped near the filler and moved around when I drove it on Sunday. That is possible..... Just hoping that the weather will clear up a little this week so I can get a real diagnosis on it. All that I know is, if it has any effect on the lash of the gears or anything like that, I'm not touching it.

From what I've been told, it's easy (I think mine is leaking but I'm going to save up for a complete rebuild instead).
1. Remove driveshaft.
2. Remover calipers and rotors.
3. W/ an in-lb beam torque wrench, measure the pre-load (amount of torque needed to rotate).
4. Reassemble the brakes and apply the parking brake.
5. Remove the pinion nut.
6. Remove the flange.
7. Remove the seal.
8. Install new seal (make sure you coat it in gear oil so it's moist).
9. Reinstall flange.
10. Tighten until preload value is reached (remove the brakes when you check). You probably will need some muscle to do it but MAKE SURE YOU DON'T CRUSH THE CRUSH SLEEVE FURTHER.
11. Once the preload is reached, reassemble everything else.
It would be a good idea to get a new pinion nut. Also, I wouldn't use brake clean to clean it for, since the last thing you want is for that to enter the diff or to cause the paint on it to melt. Just wipe it down good w/ paper towels and after you drive it, check all around it for leaks.