I just bought a 79 f250 supercab 4x4 with an automatic transmission. Can anyone tell me what this code means on the axle tag? It reads something like this:


3 54 087A TB
603901-1

 

It's a 3.54 open differential. The other stuff is build date and build info. Not terribly useful, but someone here knows what it means.

 

That kinda sucks. I figured out the 3.54 part but I was hoping that a 250 4x4 xlt would have come with a locking diff. What part of the code identifies it as an open diff and what would have indicated locking diff? Thanks.

 

The '3 54' identifies it as an open diff. Note the space between the '3' and the '54'. If it was a limited slip, it would have looked like this: '3L54'. Limited slip was optional on 4wds and 2wds. Don't feel bad, my 4x4 F350 had open diffs too when I got it. I was quite disappointed, but I remedied that situation with a Lock Right locker in the rear axle and it's been great ever since .

 

Does this code identify the axle spline count?

 

ok.. there is no such thing as a stupid question.. only stupid people..
that being said, i have a question.. and i am stupid about these things..
i know lawn mowers.. trucks are generally a new adventure for me..

A: on the code plate on my door of my truck (1979 F-250 SuperCab c-6 460) the code for my axle (2 wheel drive truck) is "37V".. anyone know what the "V" is for? i know that the 37 is 3.54 gears.

also, since i am asking questions..
B: what is an "open" differential? how is that different from a limited slip?
i do know what positive traction means..haha.. we have a special little pedal for that on my tractors..

C: would i be good off to put a selectable locker on my Dana 60? consider this. i do mostly back and forth to work. and back and forth round trip is about 5 miles... when i do have a truck (i just got this one, havent broke it in my way yet) "off"road, it is seriously OFFroad.. i dont get stuck as often as you might think.. no, it isnt all play either.. i have a farm, so when i am off road, a lot of the time, i am pulling something, or have a serious load.
so, selectable locker? lock it completely?

D: what exactly does the 3.54 mean? is that low? real low? sort of low?
i hear 4.10 this and 4.10 that? whats all that about?
now, all that being said and asked.. i have another truck that has a Rockwell rearend.. the tag on that says "Ratio: 7.17" whats that mean?

thanks for any help in my quest for understanding the complete Ford truck.

 

I like the kind of questions I can answer.

A. I have no idea what V is for.
B. Open differentials provide power to the one wheel that offers the least resistance, like the one that is in the soft mud and leaves you stuck while the other is sitting on dry pavement doing you no good. The limited slip will only allow the stuck wheel to spin a limited amount before transfering some of the power to the wheel with the good traction and pull you out of a bind.
C.It is a matter of prefence and financial status. If you can afford it, get the more expensive selectable locker. This will give you the best of both worlds.
D. 3.54 is about average for a stock truck. It is not very low when compared to 5.13 or 7.17. The number represents the number of rotations the driveshaft has to make to produce one full rotation of the axle at the wheel. In other words, the driveshaft spins about 3 and a half times before the wheel will make one full rotation.

I hope this helps you.

 

so then, open differential is something that i know i will come to hate.. i will start looking into a selectable locker.. perhaps an air locker.. that seems to be the big thing now.. (as i read 4wheel and offroad)

well, thank you for the schooling...
but what about the 4.10 thing... wouldnt that make the 4.10 lower than my 3.54? if that is case, why would you want that on a car that is for drag racing? wouldnt you want something kind of high geared? but then, i guess you really need something low to get your butt moving quicker..

one day i'll have all this figured out...
thanks again for help.
Wade

 

You're right, the low ratio is for a quicker take-off and more power after each shift. You can run a Gear Vendors OD unit behind the trans for an overdrive 4th gear for top speed.