2013 5.0 Rear diff leaking BAD (3:31s) NOT VENT

[Chaney5.0]

My 2 month old 5.0 has been leaking out of the diff clearly since day one. I only noticed it at 1300 or so miles when we were installing lowering springs and LCAs.

Now I have ordered a new steeda cover. Was a little bit more than I wanted to spend, but I would rather upgrade a part that already failed from day one with something I know won't instead of beating the dead horse and replacing something that has already failed, whether it be from installer problems or not. I also HATE with a burning passion dealer mechanics. I would love nothing more to bring a bat with me every time I walk into that place.

My first question is WHY, and WHAT would cause this on a brand new vehicle and am I the only one? I mean it is clearly bad.

My second, YES I HAVE SEARCHED FORUMS AND DONE RESEARCH, is what rear diff fluid do you guys recommend? Some recommend RP 75-140 with the additives needed already in it. I have never used RP and have nothing against them, but I hear from some very knowledgable people on a lot of occasions that they are just over hyped and aren't REALLY that great. Is this the case or are several people running these with the 5.0s and the ford rear ends? A lot of people report gear whine being illuminated.

I have been looking at red lines 75-140 with the proper additives, even though I will most likely buy a small bottle of Ford Racing Friction modifier JUST to be safe and throw in there as well. Red Line Synthetic Oil - Gear Oil for Differentials - 75W140 GL-5 Gear Oil

Anybody running that and liking it? Gear whine reduction?

Just wanting to make sure, I have only ever DD newer vehicles, and only ever done major work on old chevy BBs and ford crate engines. Newer tech is so silly you fart on the damn seat wrong and you throw a code or spit out gears on the track....

Again I have done research, it is just most talk is about trans fluid and oil. Most posts about the rear end are about gear swaps and pay no attention to what they actually put in it...

Any help is appreciated it!



Just want to enjoy this car... Barely has 2k miles, I have brake squeaking from my back left brake pad under light braking and when I turn hard/fast right... Have a bad rattle in the rear, and now this fluid leak... Good car ford!

 

[slagburn]

I also HATE with a burning passion dealer mechanics. I would love nothing more to bring a bat with me every time I walk into that place.

Well then, that rules out any chance of myself and likely several other guys here from helping with your question. Good luck :bash:

 

[13GBstang]

well then, that rules out any chance of myself and likely several other guys here from helping with your question. Good luck :bash:

^. +1

 

[Chaney5.0]

Well then, that rules out any chance of myself and likely several other guys here from helping with your question. Good luck :bash:

^. +1

Haha not being a dick, just never met one that didn't try and against laws wiggle me out of my warranty because I look to be an easy target. Not to mention they NEVER respect the inside of my vehicle. Considering it is a garage kept show car and cruiser... Sigh.

What oil do you guys recommend? The RP or Red line?

 

[acrbill]

Just use the factory fill. The 8.8 has been around a long time so there is no need to get fancy.

 

[Chaney5.0]

Just use the factory fill. The 8.8 has been around a long time so there is no need to get fancy.

This is true, but paying 10 dollars more isn't really a problem when you bought a 30k+ dollar car for some peace of mind lol :thumbsup:

 

[Ron Mexico]

I'm partial to redline but amsoil is also good.

 

[Chaney5.0]

I'm partial to redline but amsoil is also good.

Used amsoil for the motor on my last vehicle. Was pretty good!

Used red line for gears on these 8.8s before?

 

[5lho]

Redline heavy duty shockproof + 4 oz of fricmod if you're going to work it hard or lightweight shockproof and 'mod if you're not full on racing it on slicks. Don't forget the fricmod or you'll freak out in a couple days when the diff starts to moan like a man with the flu.

All that happened here is someone didn't put enough glue behind the cover. Ford uses a very light almost gasket-maker consistency stuff so, if there's any crap on the sealing face of tiny warpage, it won't seal for shit.

 

[acrbill]

This is true, but paying 10 dollars more isn't really a problem when you bought a 30k+ dollar car for some peace of mind lol :thumbsup:

Ford specs a fluid that they can stand behind warranty wise. Normal people never touch the diff fluid and drive around for hundreds of thousands of miles.

 

[Chaney5.0]

Redline heavy duty shockproof + 4 oz of fricmod if you're going to work it hard or lightweight shockproof and 'mod if you're not full on racing it on slicks. Don't forget the fricmod or you'll freak out in a couple days when the diff starts to moan like a man with the flu.

All that happened here is someone didn't put enough glue behind the cover. Ford uses a very light almost gasket-maker consistency stuff so, if there's any crap on the sealing face of tiny warpage, it won't seal for shit.

Figured it was just a seal issue, going to inspect it and see if all the teeth are good and all. I have been driving it like this, which isn't good pretty hard... Hopefully no long term damage. if so, new axles, gears, and lsd will push me to throw on some boost this time next year LOL.

What about getting the 75-140 GL-5 from red line which has the friction modifier in it?

It is an everyday driver so I will need the friction modifier. It gets driven pretty damn hard, so I want to make sure everything is spot on.

2 qrts enough? Or will I need a 3rd bottle? As it calls for exactly 2 qrts correct? I have a feeling i will be slightly short or something LOL...

 

[Chaney5.0]

Ford specs a fluid that they can stand behind warranty wise. Normal people never touch the diff fluid and drive around for hundreds of thousands of miles.

Normal people didn't take the first test drive in the car and hit the speed limiter with the salesman in it... I drive all my vehicles stupid hard. It is unfair of me to ask them to last, but getting "good enough" oil isn't going to help the car last more than 12 months with me.

:rolling: I understand ford has had plenty of time to work on good oil, but it is BS to me that it is "life time" oil... No such thing. Every liquid breaks down.

 

[acrbill]

Oh BTW the factory seals the diff cover with some sort of gray sealer, no gaskets so its easy to imagine it springing a leak. When I swapped 4.10 gears into my old manual 2011 I used Royal Purple because it was a good price from American Muscle. I also went as far as using the friction modifier too even though RP says they have it built into their fluid.

 

[Chaney5.0]

Oh BTW the factory seals the diff cover with some sort of gray sealer, no gaskets so its easy to imagine it springing a leak. When I swapped 4.10 gears into my old manual 2011 I used Royal Purple because it was a good price from American Muscle. I also went as far as using the friction modifier too even though RP says they have it built into their fluid.

I am thinking about RP with the added friction modifier. I was thing about going ahead and ordering extra friction modifier as well, but I am afraid it will make things too thin?

 

[5lho]

You'd know if you damaged anything trust me. That thing'd be howling like a banshee.

4 oz of anything isn't going to do jack, viscosity-wise, there's 3 quarts of fluid in there.

Really, do the shockproof, either one. it's worth it. You can add the fricmod a couple oz at a time if you're worried but, you'll probably need all 4, if you use the RL.

Fricmod you can get a local dealer for a couple bucks. Everybody knows it, just ask for "fish oil" and they'll bring you what you need.

What gears you have? A little easter egg Ford gives the 3.73 cars is the carbon clutches from the GT500. Others get the fibre plates.

 

[Chaney5.0]

You'd know if you damaged anything trust me. That thing'd be howling like a banshee.

4 oz of anything isn't going to do jack, viscosity-wise, there's 3 quarts of fluid in there.

Really, do the shockproof, either one. it's worth it. You can add the fricmod a couple oz at a time if you're worried but, you'll probably need all 4, if you use the RL.

Fricmod you can get a local dealer for a couple bucks. Everybody knows it, just ask for "fish oil" and they'll bring you what you need.

What gears you have? A little easter egg Ford gives the 3.73 cars is the carbon clutches from the GT500. Others get the fibre plates.

I chose a car with 3:31s as I wanted to do boost in the future and knew 3:73s would be pushing it at trap.

Can I use Ford racing friction modifier with the redline? or should I use redlines?

I'll need 3 qrts for the rear end?

 

[Ron Mexico]

I chose a car with 3:31s as I wanted to do boost in the future and knew 3:73s would be pushing it at trap.

Can I use Ford racing friction modifier with the redline? or should I use redlines?

I'll need 3 qrts for the rear end?

I used ford friction modifier with redline no problem. it's GREEN!!!

 

[Chaney5.0]

I used ford friction modifier with redline no problem. it's GREEN!!!

Nice! So last questions then I promise! did you use redline with out the friction modifier in it already? Or did you add Fords Racing Friction modifier on top of the special blend of red line with friction modifier in it already?

How many qrts of red line did you use, and did you use just one 3.8oz bottle of FR friction modifier?

Appreciate it man!

 

[shadowstang03gt]

Haha not being a dick, just never met one that didn't try and against laws wiggle me out of my warranty because I look to be an easy target. Not to mention they NEVER respect the inside of my vehicle. Considering it is a garage kept show car and cruiser... Sigh.

What oil do you guys recommend? The RP or Red line?

What is wrong with you? Try another dealer or call the customer hotline. Sounds like you have no idea what your talking about.

 

[Chaney5.0]

What is wrong with you? Try another dealer or call the customer hotline. Sounds like you have no idea what your talking about.

This isn't just with my mustang. This is with every shop. EVER. In the history of EVER.

Nothing wrong with keeping my interior in MINT condition. What happens? They guy putting the car on the lift has been underneath cars knee deep in oil. Doesn't wash his hands, touches my leather steering wheel, touches everything from the AC to my damn turn signals. Stains my seats, scratches/scuffs up my plastic trim with their shoes. etc. From exhaust shops who do work on SEMA vehicles, to shops who do turbo kits on corvettes. I have had plenty of cars in the shop. It isn't just a "dealer" thing. They HAVE to have somebody at the shop pull the car in on the lift, you can't stand anywhere around it because you're a "safety" hazard. They keep your window rolled down, so every bit of dust and dirt in that shop gets blown in your car.

It's an OCD thing. IDK about you, but I like to keep my brand new investment MINT considering this is my garage car. Was like that with 4 dodge dealers, was like that with my first f150 and 2 ford dealers, was like that back when I had my vette, and so on and so forth. Even when you approach them and tell them your concerns they say "i'll pass it on", and walk straight back into the shop and get on the phone with no ****s given.

Don't know about you but I'm not just some punk who had shit thrown at him his entire life. I take care of what I worked my ass off for. Be damned if a mechanic who doesn't give a shit and just wants to get home by 5 jumps his ass into my car. Only one person has respected that that I know of and has anything to do with cars... he details them for a living.