OD button on CV

[crabbycancer]

Real quick: does anyone know what the OD button actually does on a CV?

In my defense, though I've been on for only three years and have very little knowledge about cars in general, I haven't gotten a definitive answer from anyone at the station, or driving track for that matter.

So, does it have a practical application in our line of work? Should I be driving with it on/off, in what sort of weather, etc? Just wondering. Thanks.

[webjeep]

If you push the button it lights a little green light on the dash and turns the over drive off. When you are driving like a cop it is best to leave the OD off (green light on). If you are going to exceed 115 mph then you should turn it back on. If you are cruising a steady speed on the highway you should leave it on (green light off).

The overdrive is basically another gear. The greatest cause for transmission failure on the CV's is due to the way cops drive and excessive shifting in and out of OD. If you leave the OD off when you are patrolling your car will shift less and put less wear and tear on the trans. Your car will not go past about 118 with the OD off so if you are gonna go fast, turn it back on about 110 or 115.

Hope that explains it a bit.

-web

[rpd1794]

Also depends on what your driving environment is. If you are a city copper and stop and go alot, then webjeep is right on the money. If you patrol a mostly rural area and cruise at speeds over 55 regularly, then leave it on.

The transmission in the CV is electronicly controlled, so it will switch into overdrive if the computer thinks it needs to, even if it is turned off. You will know this is occuring because the green OD light on the dash will start to flash instead of being constantly on.

There are little to no performance advantages either way. I've been an EVOC instructor for 11 years, and I've run courses both ways just to see. On a slower course it will keep you in your power band by staying in third gear instead of O/D, but as webjeep stated, it's mostly an issue of saving the transmission from unneccesary downshifts.

[crabbycancer]

Thanks alot. Our department has a personal police vehicle program--where the vehicle we are given is ours and ours alone--so I'm really trying to take care of this cruiser, despite the constant stop and go of suburban code 3 driving. Looks like I'll be "driving with the green light on" from now on, if you copy what I'm saying.

[TPO]

Thanks alot. Our department has a personal police vehicle program--where the vehicle we are given is ours and ours alone--so I'm really trying to take care of this cruiser, despite the constant stop and go of suburban code 3 driving. Looks like I'll be "driving with the green light on" from now on, if you copy what I'm saying.

i don't see any reason to turn it off. most hard acceleration downshifts are to second gear, so whether you're in 3rd or 4th, the transmission is still going to shift. i've seen guys who couldn't keep up because they had the OD button on and forgot about it. since the power band of a CV is about in the middle of the RPMs, the top speed is actually in 4th gear, but not at redline. unless you just spend the entire day slowing down and slamming on the gas, leave it alone. most of our driving is normal driving anyway.

[Bodie]

Only time it should be taken off is if you are stuck and need to rock crusier to get it unstuck.

[Resq14]

Only time it should be taken off is if you are stuck and need to rock crusier to get it unstuck.

... I don't see what effect that will have on anything...

Here's the low-down, and how I've always understood it:
[B]
overdrive
Refers to the transmission

[USAcop]

Accelerating quicker

If you want to accelerate quicker from a stop put the shift lever in "1st gear".

The vehicle will automatically shift from the "1st gear" to "2nd gear".

After it shifts to "2nd gear" bump it into "Drive".

It accelerates quicker but isn"t the best for the transmission.