Hi

As I understand it an open diff allows the rear wheels to rotate at different speeds which to me suggests that the prop speed isn't necessarily the same as wheel speed. Which in turn suggests the prop will turn even if the wheels don't ?

So in a rear wheel car, with rear wheels on the ground and handbrake on, will I be able to turn the propshaft through 180 degrees if the car is out of gear ?

I'm ready to remove my prop on my donor at the moment and am trying to work out if I need to raise both ends of the car.

I know I've asked a couple of inane questions recently but I'm just trying to learn how things work as I go along - please bear with me !!!

thanks
Paul

No the prop will turn if out of gear with the wheels / hand brake on and the ground

The prop will turn at different speed to the wheels because of the gearing in the diff

[Edited on 3/4/10 by jacko]

[Edited on 3/4/10 by jacko]

"So in a rear wheel car, with rear wheels on the ground and handbrake on, will I be able to turn the propshaft through 180 degrees if the car is out of gear ?"

No.

You are nearly right - the prop does rotate at a different speed to the wheels but it is a fixed ratio - the ratio is usually around 3 or four turns of the prop to 1 turn of the wheels.

the reason that it is called a differential is that it allows the wheels turn at different speeds to each other in order to allow the car to get round corners.

if both wheels are locked with the hand brake you can't turn the prop.

You'll need to raise the rear end at least to remove the prop as the wheels need to be turned to get the prop to rotate so as to give you access to the bolts. Keeping the handbrake operative should help as the bolts might take plenty of effort. Give them a decent soak in penetrating fluid if you can

Ok thanks folks - I'll give them a blast with penetrating fluid now and see how I get on.

quote:

---

Originally posted by pdm

So in a rear wheel car, with rear wheels on the ground and handbrake on, will I be able to turn the propshaft through 180 degrees if the car is out of gear ?

---

http://www.youtube.com/watch?v=yYAw79386WI

Skip to 2min.

[Edited on 3/4/10 by loggyboy]

That's an excellent explanation video loggyboy - thanks for the link.

Thanks as well to everyone who replied - I'm clear on what I need to do now.

Really good explanation that!!

It's amazing how little the engineering has developed in 73 years!!