
Gearbox about to die?!?!
Moderators: timk, Stu, -alex, miata, StanTheMan, greenMachine, ManiacLachy, Daffy, zombie, Andrew, The American, Lokiel
- StanTheMan
- Forum legend
- Posts: 6824
- Joined: Thu Apr 24, 2003 11:00 am
- Vehicle: NA6
- Location: Balgowlah
Re:
JBT wrote:This should be good
been catching up.....
popcorn all around.



Satans Ride called F33nix the resurrected NA6
-
- Fast Driver
- Posts: 235
- Joined: Fri May 26, 2006 9:23 am
- Vehicle: ND - 2 GT
- Location: Brisbane
Geez...
How far of topic can we go here?
As a much wiser man than myself once said,
Tis better to be silent and thought a fool then to speak and remove all doubt.
I dont pretend to know much about gearboxes, but i do know that syncros were invented for a reason and typically manufacturer's like to make things as simple as possible. Hence, i agree with AJ and JBT that double clutching is a waste of time. For the record, my understanding of high end race cars is they typically run sequential gearboxes like WRC cars, motorbikes and the like, and as such they dont need a clutch to shift between gears once they are moving and can use air shift mechanisms like paddles etc etc.
anyway, as far as i know, WRC cars run a semi auto box anyway, which is far different from anything you will ever see in any production car...
My point in this? You cant compare an F1 gearbox to a standard OEM gearbox, nor can you relate the operation of a 125648 speed (Or however many gears they have) truck gearbox to a two seater roadster. Very different entities both ways, very different shift requirements in all cases.
My advice, and what i have always done...
Use as little clutch as possible, shift as cleanly and smoothly as possible and let the gearbox tell you when it's ready to slide into gear.
How far of topic can we go here?

As a much wiser man than myself once said,
Tis better to be silent and thought a fool then to speak and remove all doubt.
I dont pretend to know much about gearboxes, but i do know that syncros were invented for a reason and typically manufacturer's like to make things as simple as possible. Hence, i agree with AJ and JBT that double clutching is a waste of time. For the record, my understanding of high end race cars is they typically run sequential gearboxes like WRC cars, motorbikes and the like, and as such they dont need a clutch to shift between gears once they are moving and can use air shift mechanisms like paddles etc etc.
anyway, as far as i know, WRC cars run a semi auto box anyway, which is far different from anything you will ever see in any production car...
My point in this? You cant compare an F1 gearbox to a standard OEM gearbox, nor can you relate the operation of a 125648 speed (Or however many gears they have) truck gearbox to a two seater roadster. Very different entities both ways, very different shift requirements in all cases.
My advice, and what i have always done...
Use as little clutch as possible, shift as cleanly and smoothly as possible and let the gearbox tell you when it's ready to slide into gear.
Now driving a Grand Vitara whilst waiting for the elusive Black SE
- adamjp
- Racing Driver
- Posts: 519
- Joined: Thu Aug 28, 2003 11:00 am
- Vehicle: NA6
- Location: Sthn NSW
- Contact:
Agree with SirBob.
I single clutch with the Mazda, and just about any other car. Seems pointless to double clutch.
When I instructed truck driving in the Army we taught double clutching on the Unimog (dual range 4 speed Synchro gearbox with automatic range gate). The mog is dead simple to drive an is a fantastic off road vehicle. Interestingly, it has a forward/reverse lever so it is theoretically possible to go backwards at the same speed as you go forwards. Never tried that.
We taught double clutching because a) many instructors had started on the old Internationals (crash box) and b) the Mack (dog box) requires double clutching (dual range 5 speed non-synchro with manual range selection). Towards the end of my time in the Army some instructors would not teach double clutching, which made the Mack course more difficult to instruct 2years on as the students did not have a clue how to double clutch.
Once you got the hang of the Mack engine/gearbox you did not need to use the clutch at all to change because you knew what engine speed corresponded to the road speed and could simply change by moving the lever. Very cool once you got it going, but not for teaching to the students.
I believe that there is a place for double clutching, but I suspect it has little to do with the issues that started this thread. Gearbox synchros do wear out.
I single clutch with the Mazda, and just about any other car. Seems pointless to double clutch.
When I instructed truck driving in the Army we taught double clutching on the Unimog (dual range 4 speed Synchro gearbox with automatic range gate). The mog is dead simple to drive an is a fantastic off road vehicle. Interestingly, it has a forward/reverse lever so it is theoretically possible to go backwards at the same speed as you go forwards. Never tried that.
We taught double clutching because a) many instructors had started on the old Internationals (crash box) and b) the Mack (dog box) requires double clutching (dual range 5 speed non-synchro with manual range selection). Towards the end of my time in the Army some instructors would not teach double clutching, which made the Mack course more difficult to instruct 2years on as the students did not have a clue how to double clutch.
Once you got the hang of the Mack engine/gearbox you did not need to use the clutch at all to change because you knew what engine speed corresponded to the road speed and could simply change by moving the lever. Very cool once you got it going, but not for teaching to the students.
I believe that there is a place for double clutching, but I suspect it has little to do with the issues that started this thread. Gearbox synchros do wear out.
Adam
RX7AFM PortedHead 11.5:1 HKS264Cams&Gears CeramicCoatedExtractors FlowExhaust Strut&BodyBraces Eibachs Konis SparcoRims Striped
RX7AFM PortedHead 11.5:1 HKS264Cams&Gears CeramicCoatedExtractors FlowExhaust Strut&BodyBraces Eibachs Konis SparcoRims Striped
-
- Driver
- Posts: 80
- Joined: Fri Dec 10, 2004 4:21 pm
- Vehicle: ND - 2 GT
- Location: Sydney
Fatty I don't know what you were reading. But AJ didn't want to talk about the topic. He wanted to crap on about the validity of the double shuffle then wanted to start throwing the insults. People may decide how they want to drive there car and that is not the issue you may not see the point but that is up to you. If you don't want to do it don't. For the truck drivers as adamjp pointed out all gearboxes are different evens truck ones. I think if you want to argue the validity of it start a new thread.
- AJ
- Speed Racer
- Posts: 4349
- Joined: Sun Oct 30, 2005 8:27 pm
- Vehicle: NC
- Location: Gold Coast
- JBT
- Speed Racer
- Posts: 7946
- Joined: Tue Jun 03, 2003 11:00 am
- Vehicle: NC
- Location: Brisbane
Re:
midnite blu wrote:Lots of waffle not much information![]()
Plenty if you read it. If the hydraulics aren't up to it you may as well not have a clutch.
Check hydraulics, check free play. If still bad it could be a stuffed pressure plate. Last thing will be sychros in a modern gearbox.

- bruce
- Speed Racer
- Posts: 7770
- Joined: Fri Apr 25, 2003 11:00 am
- Vehicle: NA8 - Turbo
- Location: Victoria
- Contact:
- deez
- Fast Driver
- Posts: 341
- Joined: Thu Nov 02, 2006 9:20 pm
- Vehicle: ND - 2 GT
- Location: Sydney
- Contact:
Re:
JBT wrote:midnite blu wrote:Lots of waffle not much information![]()
Check hydraulics, check free play. If still bad it could be a stuffed pressure plate. Last thing will be sychros in a modern gearbox.
I'm embarassed to say this...I have no idea where to start doing the above

Mind sharing some more instructions as to how to go about the above?
Thanks guys!
89 Eunos Roadster


- JBT
- Speed Racer
- Posts: 7946
- Joined: Tue Jun 03, 2003 11:00 am
- Vehicle: NC
- Location: Brisbane
- deez
- Fast Driver
- Posts: 341
- Joined: Thu Nov 02, 2006 9:20 pm
- Vehicle: ND - 2 GT
- Location: Sydney
- Contact:
Re:
Craig wrote:Dodgy day at Deez's place!
Hahaha not a bad idea! *ponders in worry*
My place has underground garage too


89 Eunos Roadster


Return to “MX5 Engines, Transmission & Final Drive”
Who is online
Users browsing this forum: No registered users and 2 guests