Vitesse Overdrive

[WestChiltRanger]

Please can you good people give me some advice.

When driving my Vitesse, with the overdrive engaged, if I accelerate moderately hard, it feels like the overdrive disengages, but if I lift off the accelerator it cuts back in. Is this normal? Or is something possibly starting to fail.

Thanks

[Colin Lindsay]

I take it that this only happens in overdrive, not when it's off, so it's not clutch slip? 

Check the gearbox oil level as a starting point; if it's okay check the electrics. Mine cut in and out for a time, was very annoying, and started working perfectly when I cleaned the electrical contacts and bullet connectors during an annual service during which I also topped up the oil so it could have been either!

[WestChiltRanger]

Thanks for the advice. Yes it only does it in overdrive.

[johny]

Hi, definitely could be low oil but also could be the OD clutch itself slipping. Its hydraulically operated with its own pump (using the gearbox oil which is why no antifriction additives must be used), pressure relief valve and gauze filter producing pressure to engage the clutch. The slip could be due to worn friction surfaces, dirty filter, malfunctioning prv etc and when the load reduces it drives again. 

Lets hope topping up the oil does the trick as otherwise, at the very least, you'll have to remove the gearbox cover to check some of these items.

[Guest]

The other issue could be a worn cone clutch assembly.

In the photos you can see how the cone fabric has broken away over the years and where the fabric was starting to move off the rivets. Probably imminent failure before the g/box & O/D was stripped down and overhauled.

If you do have to remove the transmission, if other suggestions fail to work, this is one component you will need to check. Hopefully you will not need to get this far to rectify the issue(s).

Good luck.

Richard. 

 

[WestChiltRanger]

Thanks for everyone’s advice.

[Pete Lewis]

https://www.canleyclassics.com/y.asp?xhtml=xhtml/infodatabase/overdrivesdtype.html&xsl=infodatabase.xsl

Daves got some useful checks on here,

But start with oil levels 

Only use EP80/90 GL4 Spec oil in your gearbox

Pete

[WestChiltRanger]

Thanks Pete. What type of gearbox oil was going to be my next question.

[Pete Lewis]

there always lots of debate about modern oils but to be safe stick to the triumph spec   a more modern GL5 is easily available but this can dissolve non ferous metals in arduous hot conditions  GL4 does not 

Pete

[NonMember]

If it's a D-type, the valve mechanism can suffer wear to the bore in the casing, especially if (as with my GT6) the electrics have been faulty in such a way as to do machine gun impressions with the solenoid. When bad, you get O/D operation for ten minutes before it fails to engage, but even a tiny leak can reduce the operating pressure to the point where it isn't well enough engaged to cope with heavy throttle.

[Prince Brainier of Meccano]

Possibly just the main clutch!  My first thought was oil low and sloshing away from the OD pump.  The test for slipping main clutch is to select top gear and rev the engine and then see if the engine stalls when you lift the clutch.  If it does the main clutch is OK.  Main clutches slip more in higher gears as there's more torque on them.  To test if its the OD clutches, drive normally in OD top and accelerate.  Does it slip? Then do the same in 3rd OD.  Does it slip sooner?  Probably the OD linings as more torque is coming through to the OD in 3rd.  Hope this helps.