GEARS...Technical Question

[Kilgore Trout]

BTW, the shop manual states that the rear requires 75W140 but stupidly, before checking, I ended up buying 80W90 gear oil. Can I use this or do I need to go to the 75W140 instead?

I did the same thing but did not realize until the diff was drained. It was the only car at the shop so I had to use the 80-90 we had. That was 10k miles ago no problems so far but I will def go back to 75-140 the next time I open the diff... If you are not "forced" like me I would use the 75-140

 

[mustang70]

That FRPP kit doesn't have the wheel bearings and seals does it?

 

[Give Me TP]

Axle bearings and seals? Probably not

 

[Kilgore Trout]

FRPP has three kits, each with more stuff... Do a search on fordracingparts.com

 

[01SN8K]

is a friection modifier a MUST???
and do STOCK mustangs already come with a friection modifier in stock gears ??????

yes it is a must. the stock ford trac-lock uses clutches.

 

[Cobra Jay]

If you're only doing a gear swap, and not replacing the carrier, you don't need to add friction modifier again.

But like someone said if you go with a better gear lube, like Royal Purple it already has the friction modifier added to it.

 

[BlackenedSVT]

I am ready to purchase Ford racing 3.73 gear set which includes pinion nut and shims. Other than a speedcal, and gear lube, is there anything else i might need? The car is a 96 GT convertible 5spd with 47,000 miles.

I got my gears installed by a ford tech who has been doing it for like 20+ years. He did it for me for $200 labor as a side job at night. I ONLY bought the FRPP 4.10 gears (for my last 98GT) and the gear oil needed for like $80. And that was all he needed to install the gears.

HOWEVER, about a month later, my bearings started making noise on my axles, and they needed to be replaced (on my 98GT with about 70k miles). SO you might want to have him check the bearings while hes at it and replace them if you have a high-mileage car. Because buying gear oil twice was ****ty.


EDIT: You also may, MAY have to get your driveshaft balanced after you install the gears. Probably not with your 3.73 gears, but with my auto 98GT and 4.10 gears, there was a driveshaft vibration that needed to get balanced. The shaft would vibrate VIOLENTLY at about 100mph between certain RPMS like 4000-4500 RPM and then quiet back down at about 5000 rpm.

 

[Newbie143]

If you're only doing a gear swap, and not replacing the carrier, you don't need to add friction modifier again.

But like someone said if you go with a better gear lube, like Royal Purple it already has the friction modifier added to it.

sorry , but i'm still confused. I'm just changing to 3.73 geras. Now , will i have to get friction modifier put in there too!???or not?

 

[SilverGTV8]

Anytime you change the fluid you need to add the friction modifer. Unless you go with a fluid that already contains it, such as Royal Purple.

I don't under stand why you would say you don't need to do it if you are just doing a gear swap

So yes, you need to get the friction modifier when you change your gears unless you get an oil that already contains it.

 

[Cobra Jay]

Anytime you change the fluid you need to add the friction modifer. Unless you go with a fluid that already contains it, such as Royal Purple.

I don't under stand why you would say you don't need to do it if you are just doing a gear swap

So yes, you need to get the friction modifier when you change your gears unless you get an oil that already contains it.

If you don't do anything to the carrier other than bolting on a new ring gear there is no need to add more friction modifier to the axle after a gear swap only. The friction modifier from the factory has already worked it's way into the clutches in the carrier. All friction modifier is used for is to keep the clutches from chattering and wearing in the carrier. It has noting to do with the gears.

Go ahead and add 4 oz. if you want to it's not expensive at all, but it's not needed. I'd go with Royal Purple oil anyway and just be done with it.

 

[SilverGTV8]

Yes the oil has worked it's way into the clutch pack. But it also will come out to as the fluid is contaminated by the clutch pack wearing. By keeping it in the fluid the clutch pack will always have a supply of modifier.

You are the first person I have heard that says you don't need it.

 

[Cobra Jay]

You are the first person I have heard that says you don't need it.

Well I heard it from a guy at Sterling Axle (which is where I work) so I don't doubt it.

 

[swl987]

pinion bearing..about 20 bucks