1992F-250IDI
Full Access Member
So my 92 had 4:10 and top speed in 3rd was about 60. My 93 top speed in 3rd is around 67 to 70. I this it's a 3:73 but since my tach doesn't work I can't get an rpm in a gear to tell any help would be appreciated
No tach trying to figure out what gears are in my truck
- Thread starter 1992F-250IDI
- Start date
Jack up a rear wheel, mark the drive shaft, mark the tire, turn the drive shaft, drive shaft turns 4 times to one rev of the wheel it's a 4:10 rear, 3-3/4 times it's a 3:73, 3-1/2 times it's a 3:55 and so on.
1992F-250IDI
Full Access Member
thanks i new something like that just couldnt remember how many turns to turns of the tire
Knuckledragger
blowing chunks and grabbing porcelain
Did the OBS trucks offer another gear ratio other than 3.55 or 4.10? I have never heard of factory gearing other than those two.
Black dawg
Registered User
if one wheel remains stationary, you have to turn the tire 2 revolutions
Why?
ksingltn
Full Access Member
I believe you are correct. I've never seen anything other than those 2.
Wyreth
Certifiable Noob
The spider gears. I can't think of a good way to explain it, but the differential transfers velocity from wheel to wheel in a direct ratio. So, with one wheel stopped, you get the rotation of the driveline + the rotation of the static wheel transferred to the rotating wheel. Hence 2 rotations.
Hopefully someone can explain it better, my brain is melty today.
idi_econoline
No Bed For Me!
Glad to read this now, Wyreth. With my van apart, I was going to jack one side up and do this test, as I don't know what my Dana 60 has. Perhaps I'll wait until it's running again, and on level ground... currently on a downhill driveway!
And, of course, no factory tach on Es.......
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