Bronco Forum - Full Size Ford Bronco Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
I just baught a 78 bronco witha 351 automatic. I dont know if its got a posi in the rear end. Whats the easiest way to find out? Is there a sticker somewhere or tag im missing?
Brian
 

·
press ALT+F4
Joined
·
4,281 Posts
There COULD be a tag on the front half of the rear diff. It would be attached to one of the circle of nuts there. The ratio would be the first thing stamped on the top left of the tag as I recall. If it is a posi the ratio would say
"3 L 54" for example where an open diff would say "3 . 54" instead.
No tag, block the front wheels, raise the rear wheels, put the rig in N and turn the wheels. If both spin the same direction it's a posi. If not, it ain't. Good luck.
 

·
Premium Member
Joined
·
4,161 Posts
Actually..if you lift just one rear wheel and have the tranny in neutral, you will be able to easily turn the raised wheel if no posi..won't be able to turn it with posi. If you lift both rear wheels, leave tranny in park and if its posi, you will not be able to turn either wheel by hand..if its not posi, when you turn one wheel, the opposite wheel will rotate in the opposite direction.
 

·
Premium Member
Joined
·
3,167 Posts
bmc69 said:
Actually..if you lift just one rear wheel and have the tranny in neutral, you will be able to easily turn the raised wheel if no posi..won't be able to turn it with posi. If you lift both rear wheels, leave tranny in park and if its posi, you will not be able to turn either wheel by hand..if its not posi, when you turn one wheel, the opposite wheel will rotate in the opposite direction.
Yeah, but what happens if I have both wheels on the ground, will I be able to turn them by hand?? :popc1:
 

·
Premium Member
Joined
·
4,161 Posts
OX1 said:
Yeah, but what happens if I have both wheels on the ground, will I be able to turn them by hand?? :popc1:
Place your hand under one wheel and then let it down. I'm betting you can turn it with yr hand..adrenalin and pain being the known 'performance enhancers' that they are.

Are you bored?..or just like yanking my chain?:toothless
 

·
Registered
Joined
·
326 Posts
bmc69 said:
Actually..if you lift just one rear wheel and have the tranny in neutral, you will be able to easily turn the raised wheel if no posi..won't be able to turn it with posi. If you lift both rear wheels, leave tranny in park and if its posi, you will not be able to turn either wheel by hand..if its not posi, when you turn one wheel, the opposite wheel will rotate in the opposite direction.
Is this specific to Ford? My 78 is open and when I have the rear jacked up the wheels spin in the opposite direction. I have another vehicle (not a ford) that has a tag on the dif that says it is posi. When I jack up the rear both tires spin the same way. When I put one tire on the ground I can still spin the one that is in the air.
 

·
Registered
Joined
·
1,589 Posts
bmboll said:
Is this specific to Ford? My 78 is open and when I have the rear jacked up the wheels spin in the opposite direction. I have another vehicle (not a ford) that has a tag on the dif that says it is posi. When I jack up the rear both tires spin the same way. When I put one tire on the ground I can still spin the one that is in the air.

This just means you have a worn out trac loc. It needs new clutches and yes that is how the wheels will rotate.
 

·
Registered
Joined
·
326 Posts
RTM said:
This just means you have a worn out trac loc. It needs new clutches and yes that is how the wheels will rotate.
Could it be worn out with only 32000 miles?
Edit: I just got the vehicle. The only po was a college girl who "never put it in 4wd". Now you got me curious. I am going to go out and put one wheel on Pavement and one in dirt and see what happens.
 

·
Registered
Joined
·
326 Posts
Test results:
One tire on pavement one tire in dirt- No tire spin
Both tires in dirt- both tires spin.
 

·
Registered
Joined
·
1,589 Posts
Worn clutches. They may not have been installed/shimmed correctly. What was the break away torque reading after the rebuild? Did you add friction modifier to your gear oil? Did you drive in circles after the rebuild to help coat the clutches in oil?
 
1 - 11 of 11 Posts
Top