Hello all, I need a little help here. Even though my truck is in my signature, it is an 03 4x4 supercrew with the 5.4... My rear differential cover needs to be replaced. I know that I have a 9.75 inch differential, however the axle tag is unreadable, as is the axle code on the tag located on the B pillar. My questions are 1. Would friction modifier hurt a differential if it is not needed? and 2. Is there an easy way to figure out the gear ratio and type of differential I have without opening it first?

Thanks to all in advance.

Norm

 

whats your VIN? i can decode it for you.

and no friction modifier will not hurt anything

 

You can also securely lift the axle off the axle off the ground with the trans in neutral. Mark the tire, and a point on the truck. Also make a mark on the driveshaft (oil pen works great here). Rotate the tire on full rotation while counting the rotations on the driveshaft. For instance, if one full turn of the tire goes around roughly 3.5 turns, you have a 3.55 gear. Roughly 3.75 turns would be indicative of a 3.73 gear.

Also, you can make note of the tire on the opposite side. If it is turning in the same direction, you have limited slip. If it is going the opposite, you have an open diff.

Or, just give DJ your VIN,

 

Post the drivers side vin tag if you can. There is a ton of info on that that we can also help with. Since this is a 4x4, the front diff tag or the VIN tag listing should be correct also.

 

Maybe I am reading this wrong, but I think it is also unreadable.

?!?!?!?

 

Hmmm

 

So the B-pillar place card is unreadable ? That sucks.

You should still be able to read the stamped plate on the axle (if it's still there). You might have to clean it up first with a wire wheel or whatnot. Yea they can get corroded...white rust. Cleaning them up does wonders...since they're stamped.

 

^this

 

I thought that is what he meant by the axle tag..... but I guess maybe we'll never know, LOL. No responses back.

 

Sorry for the delay in responding....My job keeps me away at times....OK, I'm going to clarify a little here so bear with me. First is the axle tag itself, it has ben folded, crimped, twisted and creased to the point were it is unreadable, I'm guessing that the previous owner changed the fluid at some point and put the tag on one of the bottom bolts instead of higher up to help protect it, Second is the tag on the B-pillar, that tag is completely readable except for the axle code and exterior paint color code, all other info is perfectly fine. I have tried to get a pic of the tag on the B-pillar, but my camera will not focus on it when I am close enough to read it, and when I do get it to focus, it's to far away in the pic to be read. This camera was never meant for closeup work, it was meant for landscapes and large areas.
I will be going to my dealer this weekend to pick up the correct fluids for the differential, so I will have them look it up using the VIN, and if for some reason they can't come up with anything, I'll try the spin the wheel trick.

Again, thanks to you all, you've given me some ideas and options. I will post back when I find things out....