# Rotor/Axle repair - why is neutral necessary over just park?



## evan_aggie (May 28, 2009)

Everyone's instructions for working on the axles all say to put the car into neutral. Why is that necessary? Why not just put the car in park? 

Does anyone know?


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## spitpilot (Feb 14, 2000)

If you use a super duty impact gun to break loose the axle nut..you could damage the "park pawl" in the tranny..same as if someone trys to push your car getting outa a parking space...you can damge tranny by applying force to wheels while in park.


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## stratocaster (Jul 13, 2004)

spitpilot said:


> If you use a super duty impact gun to break loose the axle nut..you could damage the "park pawl" in the tranny..same as if someone trys to push your car getting outa a parking space...you can damge tranny by applying force to wheels while in park.


Exactly right. I also like having it in neutral so I can twist the axle if I need to. Those things can be a huge pain in the ass to pry out, so its nice to be able to turn them to find the right position for a pry bar to bite without damaging the axle. Obviously this isn't much of an issue with VWs since the axles bolt to an axle flange instead of going directly into the differential.


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## Anony00GT (Mar 6, 2002)

Probably so you can turn them easier, especially if you're working on the ground with only one wheel jacked up.

I've removed/installed literally hundreds of CV axles on a lift with the car in park, using an impact gun (ditto for my many co-workers), and this thing about causing damage to the transmission is something I've never heard of before. Now that I think about it, I could MAYBE see a theoretical argument for a gun causing wear on the outer CV joint, but I've never seen that happen either...the stress that engine torque puts on a CV joint during normal driving is way more than a 1/2" impact gun can deliver.


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## stratocaster (Jul 13, 2004)

Anony00GT said:


> Probably so you can turn them easier, especially if you're working on the ground with only one wheel jacked up.
> 
> I've removed/installed literally hundreds of CV axles on a lift with the car in park, using an impact gun (ditto for my many co-workers), and this thing about causing damage to the transmission is something I've never heard of before. Now that I think about it, I could MAYBE see a theoretical argument for a gun causing wear on the outer CV joint, but I've never seen that happen either...the stress that engine torque puts on a CV joint during normal driving is way more than a 1/2" impact gun can deliver.


The damage that spitpilot is talking about only applies to automatics and is very possible if you're using a gun with a whole lot of torque, although it would probably have to be at least a 1/2" gun or larger. The parking pawl is designed to be able to hold the vehicle in place when parked on level ground or at a light slant. When parked on an extreme slant, you should use the park brake as well even though most people don't realize this. 

Anyways, what I'm trying to say is that the pawl is designed to hold the car in place when everything is stationary and not moving at all. When you use an impact gun on an axle nut while the trans is in park, it has somewhat of a hammering effect on the parking pawl because of the way the axle rattles while the gun is being used. Like I said before, it would take a gun with a large amount of torque to do any damage to a pawl thats in relatively good condition. However, it can easily break one that has already been damaged over time from other things. I'm talking about things like shifting the car into park before coming to a complete stop, shifting into park while driving, being improperly installed during an overhaul, etc.

In my 6 years as a transmission tech, I've only seen this happen one time. If I remember right, it was on late 90's Ford Taurus with over 100k miles on it. Its pretty much impossible to break the pawl itself being that its made of solid steel and is usually about a half inch thick. The metal rods/springs that hold it in place are what will break if anything does.


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