rear tag number what ratio ?
 

been awhile, I have a f250 1988 4x4 that has a f350 dually rear with these numbers on the tag V170A (top line) and 10 10 26E21 (on bottom line) anyone know what ratio. front is 410 by axle code in door jam. thanks Capt. Hugh

I believe there was two options 3.55 and 4.10

H9 is 3.55 if it's something else it should be 4.10

The code in the door

You are missing a number. It is right before the 10. Under the bolt head. You have 4.10s

as Brad said, they are 4.10 gears. if they were anything other than 4.10 you would know the instant you engaged 4 wheel drive, it would feel like you were driving with the brakes applied and then you would hear a loud sickening noise as things unloaded.

thanks
 

thanks guys

rpm and speed
 

ididnt mention that the truck is a 1988 f 250 4x4 with a f 350 dually rear , speedometer not working, I just in stalled an eletric tach on steering column, at 55 mph (gps) im turning 1750rpm, that seems low to me with 410s

iirc the truck in my sig runs in that range.

Without knowing what transmission or tire size you have there's no way to calculate what the engine speed should be at any particular speed. But if I were to assume 235/85R-16 tires (31.7" dia) and a manual trans with no overdrive (given it's an '88), 55 mph would be about 2400 rpm with 4.10 gears.

If you have a C6 auto the engine speed would be a little faster due to no lockup torque converter.

If you have an E4OD with lockup torque converter and 0.71:1 overdrive you should be at about 1700 rpm with 4.10s.

Taller tires would lower all of those engine speeds, shorter tires would obviously raise them.

tires and trans
 

stock tires 235-85-16 trans = P R N D D 1 the first D is black in a white circle and a little smaller

E4OD transmission......

deleted do to double post

E4OD in '88? With that gear selector I'd take a swing at it being an AOD but I've been wrong before....

F250/350 never came with an AOD.

My sometimes inaccurate decoder ring says:

This would be a Sterling axle with a 10.25" diameter ring gear, non-limited slip.

<table style="border-collapse: collapse;" id="table2" border="1" cellSpacing="0" cellPadding="2" width="98%"><tbody><tr><td bgColor="#fae9d1">V170A</td><td>Ford F250, F350 Pickup 85-86</td><td align="center">4.10</td><td align="center">10.25</td><td align="center">NL


</td></tr></tbody></table>

AOD shift quadrant:

AOD 79 Photo by TomIII | Photobucket