Vitesse overdrive gearbox

[timeward]

Hi,

Anyone know of a overdrive gearbox for a Vitesse (or GT6) that is available?  Currently I only have a 4 speed box and poor old Vitesse gets a bit noisy above 60(ish)  

All advice would be a great help.

Tim. 

[Pete Lewis]

you can always consider fitting a 3.63 ratio diff    more available and far cheaper less hassle 

Pete

[Clive]

Saw one on Facebook earlier  £600 for the box. Seems to be ballpark for a od box these days if any good. 

Don't forget all TBD other bits required, best to get a complete conversion as they all add up to  about £300.

[Nigel Clark]

I may have a GT6 gearbox with D-type overdrive for sale in about a month's time. It's all in good working order, I'm only taking it out of my car to fit an updated gearbox with J-type overdrive to cope with the 2.5 litre engine I've fitted.

If you're interested and want to see it all running before it's removed, please PM me.

Nigel

[Wagger]

As all of those above will tell you, there are a few bits required to add an overdrive to a Non overdrive box. You need the overdrive, adapter plate, different gearbox output shaft, a shorter propshaft, a different gearbox mounting plate and all of the electrical bits.

All this to gain just one more gear. (Overdrive 3rd = ordinary top). It adds weight and is another source of unreliabilty. Yes, I fitted one fifty years ago and the result was not as good as my dreams were. It gave very little improvement in economy and failed after 18 months. I had several 'Baths' in Hypoid oil trying to fix it.

Fitting a taller ratio diff, 3.63:1, will make it acceptable at 60 mph.

It is a shame that wide ratio gearboxes are not available, or I would fit one to my 2.5 Litre Vitesse with a Quaife 3.27:1 diff. The 'Standard' 3.27:1 diff is not robust enough for enthusiastic use.

I have a 'J' type overdrive that night be available later this year, but is 'Unknown' and has no adapter plate.

 

 

[68vitesse]

In the 25+ years I've had my Vitesse broken two gearboxes, one teeth of input shaft the other teeth of third gear on the cluster. Also broken one overdrive, yellow metal thrust washer broke up, overdrives J type and you lose about a thousand RPM at 70MPH. I like them as changing the diff. ratio affects all gears.

Regards

Paul. 

[Wagger]

On some of the TR series (TR4 to TR6) overdrive works on 2nd gear. This enables a quick upshift at 60mph in 2nd. However, most TR drivers treat it with respect as It can stress the transmission mounts because of a sudden shock. I was told that the overdrive and transmission on a Vitesse could not cope wth reverse torque if switched off on 2nd gear if used to slow down.

These engines have a wide torque curve and will take a higher ratio diff. Mine will take off very smartly in 1st and achieve around 40mph. Most later cars (and many others from the same period) cannot achieve 30 mph in 1st.

What you choose to do depends upon whether or not you enjoy working on it or using it. Where I live there is not much opportunity to exceed 60 mph.

Annoyingly, my car was sold with an overdrive fitted when new, so has all of the switchery and the boot badge but no overdrive fitted. I once sold a Vitesse in this state because the buyer just wanted the 'Image' for the purpose of 'Posing'. I told him that I had robbed it of all desirable parts, but it was of no concern to him. He just wanted to polish it and 'Show off'. Some peope are very strange.

[timeward]

Hi All,

Thank you for the information and advice. I have done overdrive conversions on Spitfire’s and GT6’s before so understand the extra bits and pieces needed. 

I am a fan of overdrive and always had good reliability. I have managed to source a gearbox with overdrive and now hunting for extra bits. 

Tim.