hey every one. i just finished putting my bronco II's automatic tranny in it.
the problem i am haveing is that the rear wheels still spin when truck is in park. drive shaft wont move.
the tranny will spin the wheels when in gear. another thing is that the left rear wheel spins a lot more than the right the right barely moves.
just today it started to make an awful grinding from underneath and i dont think it was the tranny at least i hope it wasnt.
does anyone have any idea what is going on?
thanks

 

What do you mean the wheels will still spin, like if the truck is up on blocks?

 

> the problem i am haveing is that the rear wheels still spin when truck is in park

Block the wheels, set the parking brake, put it in Park, and see if you can turn the drive shaft by hand. If it is locked solid, then that most likely means something is broken in the rear axle, most likely the axle shaft.

Put the vehicle put in teh back, put in N, take off the parking brake. See if turning the driver's side turns the pass. side in an opposite direction (if an open diff) at the same speed. If not, time to remove the cover and see what broke.

 

well i put it in drive and reverse and in both directions the right tire barely moves as compared to the left which is rotating as it should. then when the truck is in park the back wheels will turn in opposite directions and the same speed. driveshaft does not move in park and is solid.

 

That is normal. You have an open differential - or a limited slip system that blew up. Open differentials allow the wheels to spin at different speeds, so you can take turns without the tires squealing. Unfortunately they give the most power to the wheel with the least traction. So if one of your wheels has "stickier" bearings, or brake shoes that might be grabbing the drum a little bit, the other one will spin, and that one wont.

When jacked up, if you turn one wheel, it will turn the other the opposite direction, that is just how the differential works. If you have a friend hold the other wheel, your wheel will not turn - as long as it is in park.

Here is an article explaining differentials:
http://en.wikipedia.org/wiki/Differe...ical_device%29

 

well i still dont know what the grinding came from.
i am thinking about pulling the diff cover to check if there is anything visible. the diff is a 7.5 so it isnt a limited slip.
i will try to see if the tire is hanging up on something but i dont think so.
i just dont under stand why the tires will move when the tranny is in park.
the tranny and the driveshaft lock in place but the tires still move.

 

Click my link on differentials. Look at the pictures and diagrams.

Here is another: http://auto.howstuffworks.com/differential2.htm

If both wheels do not have traction, you will be able to turn them freely, no matter what gear the transmission is.

Put the truck on the ground, and it will not move in park.