How do i find out what gears i have...pull cover

[84CUCV]

Its a 1980 3/4 ton p/u with a 350, SM465/ 205 combo. Any way to do it with out pulling the cover?

thanks mike

 

[POWERMAD]

Chock wheels, put in nuetral.
raise one wheel and spin it twice counting the revolutions of the pinion.

 

[K5Kell]

Just do it the right way, pull the cover. Being positive of what the gears are is worth the 15 min it takes to do the job. At least thats my opinion, but best of luck.
-Kell-

 

[smprider112]

ya...plus u get new fluid in the diff...always a good thing...they are prolly 4.10's tho if its 3/4 ton

 

[84CUCV]

it did just about three complete turns, so what does that mean? I am going to pull the cover and change it anyway,but going to look at a sub so would like to know how to tell what gears it has. thanks guys mike

 

[POWERMAD]

Almost 3 turns for a 14 FF ?
That's like a 2:something.
I mark the wheel and the yoke and have a helper spin the wheel twice while counting pinion turns.
Pulling the cover is a sure bet on getting the ratio.
3 turns and a bit is a 3:08
3 and 3/4 turns is a 3:73
4 turns and a bit is a 4:09, 4:10
4 and a half is 4:56 and so on.
Generaly I don't pop a cover unless I want to see if it is a gov-lok or what's the condition is of the insides.

 

[84CUCV]

Its a 3/4 ton truck so it is a 14sf. I will do it one more time.

thanks mike

 

[Blue85]

Remember, though, that if you turn only one wheel (open diff or gov-lock), that wheel will spin twice as many rotations as both wheels would together. So you have to multiply the pinion rotations by two OR divide the wheel rotations by two.

 

[84CUCV]

Thanks blue85. that is what i did wrong.

mike