No one seems to carry the 12 hole gasket for my rear differential cover on my 97 f150, 5.4L 4x4. Everytime they look it up it says mine should be a 10 bolt or something. How do I read the tag on the differential or does it say on my door jam sticker?

thanks

 

just get your self some RTV silicone and make your own it looks like thats what mine has on it from factory

 

even ford doesnt use a gasket....and if you did it would probably leak. just use RTV silicone like the factory does.

 

ok but since mine has 12 bolts then does this mean I have the 10.25 inch instead of the 8.8 or 9.75? Cause if so then the haynes manual and my owners guide says I need to add 8 ounces of friction modifier instead of just 4...

 

both the 9.75 and 10.25 have 12 bolts. since you have a 5.4 you will have a 9.75. unless you have the 7700(heavy duty with 7 wheel studs) then you would have the 10.25

 

the friction modifier is only needed in a limited slip axle, if you look on the axle by the diff cover there should be a stamped tag with a code on it which can be looked up to see exatly what setup you have. post up your code and i can look it up

 

The code is:If some of the silicone squeezes out into the inside of the differential when you torque down the bolts then wouldn't that be bad for it?

 

You sure there's nothing before that "55"?

Look on your door sticker - if the axle code is 19, you have a open 3.55 and you don't use modifier. If it's H9, that's LS and needs modifier.

It's definitely a 9.75.

Read this thread:

https://www.f150online.com/forums/ot...over-read.html

 

At the bottom -

 

Hey J!

Yeah mine says 19 under Axle, and under the R it has 8 whatever that means. I already put the cover back on using silicone with 3 quarts of Amsoil severe gear 75W90 oil and and a 4oz thing of Amsoil's friction modifier...that shouldn't matter that I added it even if I don't have LS right? Jbrew got me hooked on Amsoil now, I use it for everything lol. I don't know why my owners manual says to add friction modifier and makes it sound like I have the limited slip...

 

How it goin D - I got yuh hooked ehh, - That's easy with the good sh^t ..

#19 -= 3.55 NON limited slip.. OOOPS!! - In the 8.8 (10 bolt) and 9.75 (12 bolt) rear ends.

 

Axle Codes

The following lists the gear ratios on rear axles.

19-3.55 non-limited slip (Econoline, F-150)
18-3.08 non-limited slip (F-150)
17-3.31 non-limited slip (Econoline)
H9-3.55 limited slip (F-150, F-250)
B6-3.73 limited slip (F-150, F-250)

If you put 4 oz's of FM in the rear, it's not going to hurt it. That's good stuff, I run a little of that in my trans


Yea the "8" is a radio code -

Radio Codes

8-AM/FM stereo with cassette, Premium Sound (Econoline, F-150, F-250)
7-AM/FM stereo with clock (Econoline, F-150, F-250, Ranger)
9-AM/FM stereo with cassette and clock (Econoline,F-150,F-250,Explorer/Mountaineer, Ranger)

 

Well damnit, I was hopeing I had a limited slip...thanks for posting that, I have been meaning to search around for a description of the door jam sticker codes.
So what is the best gear ratio for larger wheels/tires? Cause I noticed my truck sure seems to work a lot harder when I have my 35's on it than with my stock 17" wheels/tires. Which is of course to be expected, but since I do have the bigger 5.4L I didn't think it would have to push THAT much harder with my bigger wheels/tires on it. I mean, I get like 220 miles to the tank with my 35's on it and when I put my stock tires/wheels back on I get like 350+ miles to each tank. So that is a pretty big difference...So then I figured my rear end gears probably have a lot to do with it...

 

and it says 5.5 pints but with 3 quarts of gear oil and 4 oz of FM mine is still below the fill hole, I can feel it with my finger though, but it didn't come flowing out when I filled it up or anything so I hope that was enough...

So what does econoline mean anyway?

 

Econoline is a van, like the delivery vans. Completely diff from the mini vans.