Transmission Locking

[ChrisMinelli]

How does the transmission lock the rear wheels when you turn off the engine in reverse or first gear?

 

I’m doing some work on the car now (52 Plymouth) and I’m putting my rear drums back on.  When I stopped the car I had it in reverse and turned off the ignition so the rear wheels locked.   I shifted the car into neutral (up on jack stands) to rotate the rear wheels.  
 

I’m ready to put the drums back on and torque the axle nut but the rear wheels still spin when when I shift into reverse or first gear. 
 

Does the engine have to engage the transmission for the axle to lock in gear?  Anything I can do without starting the car?

 

Thanks!

 

[martybose]

Nothing you can do at the transmission will lock the rear axle to torque the nut, because the differential will allow the wheels to turn (in opposite directions) even if the driveshaft is locked.  You will have to install the wheels and set the car on the ground to torque the nut.

 

Marty

Edited May 5, 2020 by martybose
typo

[greg g]

Put the lug bolts in part of the way. Use a piece of wood arranged through a couple bolts to contact the floor to resist the movement.

[Sam Buchanan]

2 hours ago, ChrisMinelli said:

How does the transmission lock the rear wheels when you turn off the engine in reverse or first gear?

 

I’m doing some work on the car now (52 Plymouth) and I’m putting my rear drums back on.  When I stopped the car I had it in reverse and turned off the ignition so the rear wheels locked.   I shifted the car into neutral (up on jack stands) to rotate the rear wheels.  
 

I’m ready to put the drums back on and torque the axle nut but the rear wheels still spin when when I shift into reverse or first gear. 
 

Does the engine have to engage the transmission for the axle to lock in gear?  Anything I can do without starting the car?

 

Thanks!

 

 

The transmission doesn't 'lock' the rear wheels when it is parked and in gear. What seems to be 'locking' is actually the compression of the engine preventing the wheels from rolling. Push hard enough on the car when it is in gear and the engine will turn over.......that is how we bump-start a car with a bad starter. 

 

Torque the axle nuts as much as you can with the car jacked up (they won't be very tight) then lower the car enough to put enough weight on both wheels to prevent them from turning as you lean on the big wrench. I also chock one of the wheels, and setting the parking brake will help if you have a good brake. Torque to at least 140 ft-lbs and insert the cotter pin. Recheck the torque after you put a few miles on the car, the nuts can probably be turned another slot or two.

Edited May 5, 2020 by Sam Buchanan