Hello,

I own a 1997 F150 V6 4.2L w/ 5 sp manual transmission. My differential is making a whining noise while the truck is in gear and under load.
I am thinking of replacing the whole differential with a newer one that it has discs brakes as well.
I was trying to find some older threads in order to get the correct information about doner cars, ratios, etc,
I would really appreciate it if you guys have done this mod or have info about it that would guide me in the right direction.

ty.

 

If it's 2 wheel drive, ratio isn't all that important, except you would need a different speedometer drive gear if it's a different ratio. What is the AXLE code on the door jamb sticker?

Any 8.8" axle assembly from the same generation F150 should bolt in, those will be found with the 4.2 and 4.6 engines. Brake components will be different.

Have you checked the diff fluid level? Has it ever been changed?

 

It is rear-wheel-drive.
The axle code on the door jamb sticker is 19. If I am correct that is the 8.8 axle with the 3.55 gear ratio.
So any F150 differential with a 4.2 or 4.6 engine would work? Automatic or manual doesn't make a difference?
How about the drive shafts?
I know I need to modify a little the emergency brake cable in order to adopt.
How about the rear brake proportion valve? Do I need to replace it?

@glc thank you for your prompt reply as always.

 

Any 1997-2003 F150 8.8" axle should work, transmission doesn't matter, driveshaft will bolt right up. Yes, you have 3.55, non-limited slip. 3.55 is the most commonly found axle, you may be able to find a H9 limited slip. My 03 4.2 manual is H9.

I don't know how involved the brake swap will be. I do know that you will have to replace the parking brake cable and flexible rubber rear brake lines, it may use a different proportioning valve, I don't know about ABS compatibility

 

Thank you very much.

 

@glc Do you know if the H9 has the 12 or the 10 bolt cover?
I found an H9 at the junkyard out of a 2000 F150 automatic.
The rear cover of the diff had the 12 bolt cover so I am not sure if it's the original H9 or even how it looks.
It is for sure different in shape than my 19 axle code differential.

ty.

 

The one you found is probably a 9.75" rear. If the truck had a 5.4 engine it does. Does your current diff have a ten bolt cover? The H9 just tells you the gear ratio and that it has traction lock. It does not tell you the ring gear size. The diff should have tags that tell you the ring gear size.

 

4.2 and 4.6 have 8.8" rear, 5.4 has 9.75" rear, 7700 package has 10.25" rear and 7 lug wheels.

 

If it is a 12 bolt, and h9 - that is a 9.75" rear end from a 5.4L that has the lsd and a 3.55 ratio. Disc brakes also

 

Hello guys,

I finally found from U-pull-it an H9 (3L55 8.8") diff from a 2000 F-150 V8, 4.6L.
I am in the process of rebuilding the diff, with all new bearings, seals, spider gears and clutches.
My question is if I can replace the 14mm wheel studs with 12mm wheel studs on the same axles (31 spline) from the doner vehicle,
or if I could I use my original axles from the (19 code diff- 3.55 8.8").
Please advise.

 

You will have to pull the axles and do a direct visual comparison. They may or may not be interchangeable. I do not think you can put 12mm studs into a 14mm axle.

 

thank you @glc