need diff help
 

W123 on stands, in park, should I be able turn rear wheels by hand?

No, they will not turn when the transmission is in park.

Think about it. when you park the car in the garage, in a parking space at the Mall etc.... and you throw the shift lever in Park (With out using the parking brake) this holds the vehicle from rolling away. the park position locks the transmission from turning. there is a Pall in the trans that holds it from turning.

Shift the transmission to neutral, and you should be able to turn the wheels, as long as the Parking brake is not applied.

Charlie

I'm thinking that the wheels would turn unless it is a limited slip differential. The driveshaft would not turn due to the parking pawl, but turning one wheel would cause the other wheel to move in the opposite direction at the same speed.

I'm thinking your wrong otherwise your car would roll away if you didn't use the parking brake.

mach4 is correct.
this is the reason you HAVE to use wheel chocks when you are lifting a rear wheel off the ground and the car is not on perfectly level ground. the emergency brake is not adequate to hold a vehicle still with one rear wheel off the ground.

Unless your emergency brake is on... yes.

vstech your saying that with both wheels off the ground, parking brake off, and transmission in park the wheels can be turned by hand?

This is correct. However, the wheels will turn in opposite directions due to the differential. The pinion is locked by the transmission and the two wheels are free to rotate on the spider gears.

Yup.
unless you have an extremely ultimate rare Limited Slip Diff under your 123...

and if you do... I want it.:D

Iam thinking the same as you.
I bet 90% of the drivers out there just throw it trans in park, jump out and go on their way.
The majority don`t even know what the parking brake is for.

So if the wheels will turn when the trans is in park? then what keeps the vehicle from rolling away?


Charlie

Answer
 

With both rear wheels OFF the ground.

The wheels will turn in opposite directions due to the differential.

The pinion is locked by the transmission and the two wheels are free to rotate on the spider gears.


With both rear wheels ON the ground, transmission in park.

The wheels will try to turn in opposite directions due to the differential = no motion.


.

Yep, one wheel spins one way and one spins the opposite.
Unless it is a limited slip differential.
I spin the rear wheels in junkyard as I pass buy hoping to find a limited slip differential.
Found two so far but not on the diesels. Both very low gear ratio differentials on models with larger gasoline engines.
Also I believe the limited slip differentials have a small tag on one of the cover bolts specifying the different oil used in those differentials and the gear ratio.

You could get the vehicle to roll in a circle if the front wheels would turn to 90 degrees.:D

Thanks for the responses. I am back square one...............
Something went bang, now the car don't move. I was
thinking tail shaft first. but it is locking into park.

Well I learned something today. I know the wheels will turn in oposite directions when the transmission is in neutral ( and wheels off the ground) but thought when in park it locked both back wheels from rolling in either direction.

I need to rotate the tires on the 240, I`ll see how this works with a manual transmission in 1st gear. Probably the same as an auto in park?

When Iam in PNP and disconnecting a drive shaft, I throw the trans in park to keep it from turning when removing the flex disc bolts. the DS is connected to the transmission so it won`t turn and the wheels/axles are connected to the differential and Spider Gears and will let each rear wheel turn in oposite directions.

I guess I just never gave it much thought before.


Charlie