What does overdrive mean?

[ej2095]

Was sat at petrol station waiting rev up and pulled up to pump and a message popped up on mult display saying overdrive off?

Mind i do keep catching the stalks as well with my knees.

Car runs fine but what is over drive?

[spider]

What vehicle ?

I guess its not being used in its 60's / 70's terminology anymore though ie legacy 3.5 4.5 gears, I was going to say 5th but it tended to work in more than one ratio.

Auto ? , Some autobox's count 4th (or 5th) as 'overdrive' , ie only use the first three / four ratios.

[411514]

Was it a C5, if so was it overspeed, which is just an adjustable warning that you can set when the car exceeds a certain speed.

[Chlorate]

Generally speaking, overdrive is when the output shaft of the gearbox is moving faster than the engine.
Often in a 5 speed gearbox 4th is 1:1 and 5th is slightly overdrive.

Back in the day, cars would have a separate overdrive gearbox to add a little more high gear i.e. the 3.5 & 4.5 gears Spider mentioned. And this could be engaged/disengaged at will.
I have no idea if anyone is still fitting them to cars

What car is it?

[isisalar]

'Back in the day' one of the most interesting old cars I owned was a Triumph vitesse. It had a 1600cc 6Cyl engine, twin SU's, and overdrive on third and fourth. Very smooth and fantastic torque.
Who said 6 speed speed gearboxs were a new thing?
From memory I think it was a1965.
Cheers
Paul

[handyman]

Yes, but the real trick was to drop in the 2.5 PI engine with overdrive, and modify the selection plate so you got overdrive in 2nd as well! I did a few of these conversions for Vitesse and GT6 owners who were more than happy with the transformation.

My own 2.5PI was so modified and also fitted with a 357 cam and an LSD. Could easily see off any F*rd Capri at the traffic lights drag! Gave it a seven speed gearbox with no wheelspin, only traction.

H

[ej2095]

yes c5 hdi 2.2

[ej2095]

and could have been over speed lol

[lexi]

Hey Handyman, I had a big 2.5 pi with the Laycock O/D. 5yrs I had it. That trick of sitting behind a car in o/d third and then hit the switch to drop to third, was brill. They were special at the time.

We are still using bolt on overdrives with old Land Rovers. They are Fairey and pretty whiney things.

[JohnD]

In the late '70s I bought a Transit to convert into a motor caravan. It was fitted with Ford's 2.4 York diesel engine. I heard of a guy in Essex who converted Transit gearboxes into overdrive boxes my grafting on the overdrive from Zodiac cars. I decided to have mine done. What a transformation. By the flick of a switch, speed was maintained but revs dropped right down. Overdrive worked on 2nd, 3rd & 4th, so really you ended up with a 7 speed van.

[Old-Guy]

TR2 and later a Triumph 2000 estate both with overdrives.

Hey Handyman, I had a big 2.5 pi with the Laycock O/D. 5yrs I had it. That trick of sitting behind a car in o/d third and then hit the switch to drop to third, was brill.

Then flick the switch back into overdrive as you go past - with 3 kids and a black lab in the back!