Clutch when using Overdrive?

[Bazzzaboy]

In 3rd or 4th gear, I simply click my overdrive in when changing up the gear. But wen going down the gears, if in 3rd and I switch the overdrive off, it feels as though the car is saying "use the flipping clutch matey!!"

A bit of a lurch - that's all.  So...is this the correct procedure for using the overdrive or is there a well respected technique??

[nang]

I once had a Sunbeam Rapier which had a bad oil leak around the o/d unit. I followed the book instructions "undo nuts and slide unit off gearbox".
No way could I do this, it moved about 1/4" and no further. As I'd broken the seal I ended up with gearbox out, a couple of bars and finally managed to get unit separated from box. The splines on the shaft were twisted.
Since then I ALWAYS use the clutch when going in or out of overdrive.
Tony.

[JohnD]

Were the 1st & 2nd gear inhibitor switches working?
Trying to use O/d in a low gear is THE way to twist the input shaft.
Jhn

[Billus99]

I don't use the clutch putting o/d on, but do tend to when switching out at higher revs to stop "that lurching feeling", unless I've already slowed right down

[Nick Moore]

I don't use the clutch when switching in or out under power, ie cruising or accelerating, as there's hardly any lurch. However, I do dip the clutch on the over-run, ie slowing down.

[piman]

Hello all,

my 'A' type is happy with full power engagement and is instantaneous, switching out I just increase the engine speed.

Alec

[Andy Flexney]

basically you have to ensure the input shaft of the gearbox is running faster than the output shaft of the overdrive.
That means do it as Alec says.
If on overrun i.e. using engine braking use the clutch.

AndyF

[ferny]

I alway use the clutch. I'd much rather have a controlled and smooth impact on the components on the car.

[bxbodger]

There's no need to use of be clutch, I never have, I just switch it on and off as required. Provided you have clean oil, and the inhibitor switch works,  you should barely notice it  engaging/disengaging, there certainly shouldn't be thumping and lurching. They work exactly the same as an autobox- sun'n'planet and brake bands,  and those are driven completely without thought  or clutch.

[Dogsbody47uk]

Quoted from bxbodger

There's no need to use of be clutch, I never have, I just switch it on and off as required. Provided you have clean oil, and the inhibitor switch works,  you should barely notice it  engaging/disengaging, there certainly shouldn't be thumping and lurching. They work exactly the same as an autobox- sun'n'planet and brake bands,  and those are driven completely without thought  or clutch.

I agree.

[nang]

Quoted from ferny

I alway use the clutch. I'd much rather have a controlled and smooth impact on the components on the car.

I agree with ferny, unless you match the revs between engine and drive you surely must be putting undue load on mismatched components.
Tony.

[Pete Lewis]

as the overdrive engagement has varying damping with types ,and conditions , a light feather on the clutch or a lift off the power is a good thing ,
it feels better for the neck jerk to the passengers and having been involved with testing Commer vans fitted with these units a dab or a dip was normal test proceedure
for Rootes ,to smooth the change and yes extend the lining life .

whack it in or whack it out its your preference and your ££s  if Parker did that he would get the sack from lady  Penelope     Ha !

Pete

[Pete Arnold]

I have never used the clutch when switching out of overdrive in my 1967 MkI Vitesse.

I happen to have 2 different versions of the "Triumph 2 Litre Vitesse Owner's Handbook".
For info, I attach copies of the relevant page from each copy showing the advice for Overdrive Unit use.

You will see that maximum disengagement speeds are shown for 3.89 diff in the 1st edition which is dated 1966.
In the later edition, undated and published by Brooklands/Heritage, these mph recommendations are replaced by a maximum disengagement speed of 4,800 rpm.

All other wording is exactly the same in both versions.

[Stu 1986]

This is an interesting thread, I was curious about the method of using the O/D. I haven't used it on my car yet as it isn't finished, but I was wondering how to use it.

I do have a couple of questions though; Why does it work on 3rd gear as well as 4th? When would you use it on 3rd?

Ta, S.

[Mark Hammond]

For fast rapid acceleration to overtake, the change from O/D 3rd to direct 3rd is virtually instantaneous.  Whether you use the clutch or not to operate the O/D is a matter of personal choice.  There is no right or wrong.

Mark

[Saltddirk]

Quoted from Stu 1986

When would you use it on 3rd?

Ta, S.

I use it a lot on twisty bits, just have it in 3 OD and when you approach a corner, switch out of OD, Power through the corner, flick on again till next corner.... I mostly use 3 - 3OD- 4OD, hardly go to 4 anymore. The difference between 3 OD and 4 is marginal.

As a reply to the OP question, I do not use the clutch normally, might do but not systematically. As to the rev limit/ speed limit on disengaging, that is I believe because you risk of over -revving the engine.
I once had the OD disengaging while on the motorway at full blast, not to be recommended or repeated.

D

[Billus99]

Damn, i was quite happy driving my car and using overdrive, now I can't help "analysing" what I'm doing every time I change gear!

[Harveyzone]

Quoted from Saltddirk

I use it a lot on twisty bits, just have it in 3 OD and when you approach a corner, switch out of OD, Power through the corner, flick on again till next corner.... I mostly use 3 - 3OD- 4OD, hardly go to 4 anymore. The difference between 3 OD and 4 is marginal.

Agreed. Also quite useful about town, rather than having to keep change up and down to forth.

I never use the clutch either.

[Dogsbody47uk]

In my 13/60 with 4.11 diff, od 3rd is useful in 30 mph zones; normal 3rd is too low and a bit revvy but od 3rd is ideal.

[RobPearce]

Quoted from ferny

I alway use the clutch. I'd much rather have a controlled and smooth impact on the components on the car.

I never use the clutch. There's no point. The overdrive itself is a clutch (well, two clutches) and if working correctly is set up to engage them as smoothly as you need.

[Straight Six]

In my experience, different overdrives require different techniques. In general J Types seem to be smoother in operation without clutch use than D Types. However, I’ve driven D Type equipped cars which go in & out of overdrive very smoothly, and others where you need to use the clutch on engagement & disengagement.
On my D type, I use the clutch to engage it unless at full throttle when it will go in smoothly, and give the throttle a blip on disengagement to avoid the lurch, which can be quite severe if I disengage on the overrun.
The comments about an overdrive not needing use of the clutch are probably correct, but all the easy adjustments on my overdrive are correct, and the oil is clean so I’ll live with dipping the clutch occasionally rather than ripping it apart to look for a problem.
So in short, my tuppence worth is; if it jolts or lurches use the clutch, if it doesn’t then you probably don’t need to use the clutch.