Overdrive disengaging

[David Gee]

Triumph Vitesse 2 litre Mk 2, HEO 917H

VIN HC54909CV
Engine HC54826HES

My car had an overdrive conversion kit, from Trading Triumphs of Northwich, fitted in 1997. Presumably it was a reconditioned unit at the time. I bought the car in July this year and for the first 200 miles I've done the overdrive worked perfectly. Then it suddenly disengaged and would not re-engage during the remaining 50 miles of my journey.  The next day it worked fine for about 50 miles and then the same problem recurred.  It seemed the problem could be with hot oil being too thin so I had the oil changed.  Since then the overdrive has been fine on various short journeys but it disengaged again after about 15 miles; and the same happened on the return journey.

I've been told I may need a replacement reconditioned unit at a total cost, including refitting, of about £1,000.  However, I'm hoping there's a much simpler and cheaper solution, possibly involving  the wiring, solenoid or pistons. Any suggestions would be VERY MUCH APPRECIATED!

Interestingly, I was able to lease a new Vitesse Mark 2 in 1971. I loved it but it had the same overdrive symptoms! They were cured, at the second attempt, by a Triumph dealer but I don't know what they had to do.

[Velocita Rosso]

A multitude of answers will come from this question
For example,oil pressure, changed the oil?....but did you just top up the gear box on the flat? there is a lip between o/d and gear box
I jack front end up of car and allow more oil to go into the o/d.
O/d springs could be weak
....and the list goes on
£1,000.00?......no where near
Ring the usual suspects....then there is O/D Services (Yorkshire)...get a price....then all it means if you want to exchange is drop the box and swap over
PS J Type?....you can borrow a pressure gauge and screw on to the bottom of o/d and check the pressure

[yorkshire_spam]

There's a number of possibilities, blocked filter, piston adjustment, solenoid adjustment.
http://www.canleyclassics.com/technical-archive/the-d-type-overdrive/
I guess the "cheapness" of the solution depends a bit on how much you can DIY?

If you can't repair/adjust yourself you probably should talk to somebody like Mike Papworth about an exchange recon unit (assuming you could fit it?)

[ferny]

Ask the person who advises a replacement what exactly is wrong with yours. I doubt they'll be able to tell you as if they could, they'd advise repairing/replacing/adjusting that part...

[dazzer]

Could be as simple as a loose wire on the solenoid or relay (if fitted) Had the same symptoms it was a loose wire.

[RobPearce]

Had similar symptoms on a Stag but only in fourth (3rd OD was fine). Turned out to be a mis-adjusted (well, mis-fitted, really) inhibitor switch. The design is different on the Vitesse but similar issues should not be discounted (especially as the fix for that required no parts and only cost my time).

[daver clasper]

Hi

Had those same issues on my my J type (as well as engaging when disconnected.)

Dave Twigger, Overdrive Spares, Rugby (very helpful), advised, cleaning solenoid and replacing internal o rings for reluctance to engage/disengage and changing o rings in pressure relief valve (located at bottom of O/D).
This involves removing a plug for which a special tool is no longer available, I think (I unscrewed it with a hammer and punch).
Bit fiddley, but did it 3 years ago and O/D been fine since.
Buckeye Triumph have detailed info of this job online which is a must, I would say.
Dave