Hello + Overdrive problem on new Stag.

[MGBV8]

Hi everyone!

My name is Jon and I run a musical instrument restoration and repair business with my other half in Derbyshire.
We only drive classic cars. Modern cars just don't really do it for us! We currently have 2 classics - a '75 MGB GT Factory V8 and the latest addition to the fleet behing a chocolate brown '77 Triumph Stag. The car is manual overdrive and still has the original (recently rebuilt) Triumph V8.

The car has developed a bit of a strange problem with respect to the overdrive.
After a days driving, coming down a hill in third gear with overdrive engaged, it suddenly decided to switch out and re-engage.
This happened a few more times over the course of the remaining mile back to the house. By the time we got home the o/d wouldn't engage at all.

I've checked the wiring in that I've checked with a test bulb that there is current going to the gearbox with the engine running, gear lever in the 3rd / 4th position on the gate and eliminated the switch.
I've also drained the oil in the gearbox, cleaned out the mesh filter with carb cleaner and reassembled and refilled the box with EP90.

Since doing that, very occasionally I am able to engage the overdrive. However, when I flick the switch, the overdrive will engage for around 1 seccond and switch straight back out again on it's own. If you try and get it to engage again by flicking the switch it won't attempt to engage. However, if it is left for at least 10 minutes it will repeat it's 'in for 1 seccond and straight back out' antics.

I'm a bit stuck as to what to look at next. Clearly the o/d works in that it actually engages momentarily so there *should* be some sort of fix underneath the car without having to resort to taking the gearbox out?

-JC.

[jleyton]

Hi JC,

Welcome to Stag ownership and to the Forum - let's hope you become a regular on here

When I first started reading your post I thought it was bound to be electrical - usually in the loom up the gear lever to the switch - but you appear to have ruled that out.

As a 77 car, you'll have the J type overdrive. I had a similar problem to yours some time ago and without any of the pressure test equipment I took a gamble on the solenoid and it cured it and I would have thought there's a good chance that that is your problem. Replacing that is both easy and hard ! It's just two wires (refit either way) and IIRC a 1" spanner to unscrew it. However the spanner needs to be only about 1/8" thick and about 4" long !! If you tell us where you live then maybe someone local to you could lend you a spanner.

Unfortunately, solenoids are quite expensive, especially just to try and see if that's your problem. Again, maybe someone on here has a spare they could let you try?

Now I see what I've written I'm not sure if I've been helpful or not - maybe others will come along with something more useful.

Cheers

Julian

[MGBV8]

Hi Julian,

Thank you for your prompt reply and warm welcome. I am based in a little village called Shirland, just outside Alfreton, Derbyshire.

My initial suspiciouns were the same as yours. However, I'd now put money on the electrical side of things being right? The multimeter said there was a steady 12 volts going to through the switch which rings true?

I'm wondering if it'd be worth draining the box again and changing all the o-rings? The odd thing is this gearbox was only rebuilt about 6 years / 5000 miles ago. So, with that in mind, I'd have thought that the internals would be O.K and not need any intervention?

Is there an oil pressure relief valve built into these units? If there was a bit of rubbish holding the relief valve open, that might explain things, perhaps?

best regards,

JC.

[Sheepdip]

The A box I played with had similar solenoid problem, there are contacts in the end which reduce the power load when engaged, if these aren't working then will fail (although more likely to totally stop working). Its worth taking off and checking, not familiar with J type but if you can take teh actuator off as well, stick 12v on it, monitor current and make sure its pulled in hard (and stays in). If you can get to contacts even better

[AlanD]

Hi JC,

welcome and not too far from me, where in Derbyshire are you

[grumpy2]

MGBV8, is the name I use on another forum from years ago. guess we have a similar choice in cars. How do you find the stag compares with the MGB V8? I think the stag is more refined but the MG shedloads faster! the MG is also about 50% more economical. What do you think?

Gary

[stag8manod]

Hi JC, What you have cleaned is the suction filter. Up in the main case behind a pin plug is a caged pressure filter. It requires a pin wrench to operate it. I have made one but NZ is a bit far away. I will be home in NZ from England after 5 weeks on Thursday and could supply the dimensions if you wish. I did give these to another member sometime ago I'll have a search and see what I find.
Cheers Ian A

[stag8manod]

Hi Jon, I started a search then realised i was in the old forum and gone. Unless the member I posted to sees this and can help.

[jleyton]

Hi JC, Up in the main case behind a pin plug is a caged pressure filter. It requires a pin wrench to operate it. I have made one but NZ is a bit far away. Cheers Ian A

If you decide to remove the pressure filter, there's a trick that I've used successfully several times to remove fittings that should have a pin wrench.

If you can get a couple of small bolts, or even screwdrivers, that fit fairly snugly in to the holes then you can put a screwdriver between them at 90 degrees and twist - effectively making an 'H' shape.

It worked for me a few months ago when I removed the filter on my J type - whether it will fix your problem or not is another matter though.

Cheers

Julian

[jleyton]

Hi JC,

Sorry, I completely missed your earlier post somehow

There is a pressure relief valve in the overdrive but I have to say that, although I understand the principles of O/D, the workings still remain a bit of a mystery to me.

However there is a brilliant resource that answers just about everything here: http://www.buckeyetriumphs.org/technical/technical.htm although it's a site dedicated to TR's there are quite a few things that relate equally to the Stag, such as the Overdrive. Allow yourself a couple of hours to read it all though

For me though, now you've ruled out an electrical problem, my gut feel suggests solenoid.

Good luck and cheers

Julian

Ps Re electrics, I've just noticed that you said "The multimeter said there was a steady 12 volts going to through the switch" - that's good but, of course, the critical thing is that the 12v gets to the solenoid and the wiring under the car is in a pretty vulnerable position - I'd check that out as well.

[MGBV8]

Thank you for the replies, folks.
I guess it seems the consensus is pointing towards the need for a new solanoid, then? Looking through other threads it would suggest that these are prone to failure?

AlanD, my other half's parents live in Ripley. Small world, eh? We are based in Shirland which is the first village out of Alfreton down the A61. No doubt we'll be taking the Stag and the MG along to the classic car meet at White Heart just outside of South Wingfield on the 6th of September. See you there possibly?

Grumpy2, I know a Gary Noden of Hope, Chester. Are you the same person?

Stag8manod, thankyou for trying! You wouldn't happen to know what diameter the pins are by any chance? I've spotted this tool on ebay and wondered if it might be worth a punt? http://www.ebay.co.uk/itm/1405814053...84.m1423.l2649 or ebay item: 140581405390

Julian, you didn't miss my post. Everything I write as a guest member has apparently got to be approved by a moderator before it goes live. Presumably as a way of keeping spammers and plonkers from disrupting the forum?


With respect to tracing the wires down to the solanoid, how do I remove the wood trim from around the gearlever? Nicola hasn't bought us a workshop manual yet!!!
Thanks once again folks. All advice is much apriciated.

-JC.

p.s anyone know where I can buy one of these skinny spanners or have I got to buy a new grinder?

[MGBV8]

Gary,

RE: Stag vs MGB GT V8 - I think they make a pretty good pair.
In terms of fuel economy, our Stag has managed 21.5mpg over the last 250 miles. Although, there are improvments to be made - it was running like a pig when we picked it up having not been very far in the last 3 years and there is of course the lack of overdrive over the last 50 miles or so to factor in. I think a decent tune up and resolving the o/d issue will likely bring the figures up a little. Although, I can't see it changing too much - Nicola has a class B race licence and a lead right foot and I'm not much better!
The MGB GT V8 had 36k from new when we picked it up in April - I'd been specifically looking for a Rubber bumper model without a sunroof for about 6 years when this one finally turned up and I've started playing with it. I've junked the twin SU's in favor of a 4 barrel webber so she's only doing about 22mpg at the mo. Whilst the Stag will be staying pretty stock, the MG is evolving into a 70's styled hotrod.

Back to back, the Stag is a much more comfortable cruiser. It feels much more like a modern car with power steering, comfy leather seats and well silenced V8 make it a much more civilised car to drive. The MG is a lot harder in terms of ride quality and it accelerates a damn sight quicker than the Stag and will do much higher speeds. The gear selector action is about the same, however the general controlls of the Stag feel a little lighter compared to the B and I would say the stag has the edge with respect to the heater.

If I had to make a journey down the motorway or go for a gentle cruise, I'd probably plump for the Stag. By the same token, if I wanted to go for a thrash down the local B roads, I'd be reaching for the keys to the MG. To that end, there's a suitable choice between the two no matter what mood you're in. That said, had I been alive at the time to spec a brand new one, I wouldn't have picked Red for the MG and neither would I have picked Russet Brown for the Stag. I'd have gone for Aconite / Magenta respectively!


-JC.

[jleyton]

With respect to tracing the wires down to the solanoid, how do I remove the wood trim from around the gearlever? Nicola hasn't bought us a workshop manual yet!!!
Thanks once again folks. All advice is much apriciated.

-JC.

p.s anyone know where I can buy one of these skinny spanners or have I got to buy a new grinder?

Hi JC, (Glad to hear that I wasn't going barmy and missing posts completely )

To remove the wood trim, you have got to gently lever up the black plastic trim that separates the gear lever surround from the small rectangular 'coin tray'. The coin tray will come up with the trim although if this hasn't been removed for a long time the plastic can go hard and it may be reluctant to come out But, keep at it as it is only pushed in to place. Once this is out you can see the screws retaining the gear lever surround.

Once you've checked all the wiring up and down the gear lever, I'd certainly be checking the wiring under the floor (easier said than done I'm afraid) that leads to the solenoid. If you can get the car on a ramp this'll be a lot easier.

As for the thin spanner, I'm not sure that a company has ever sold one - I think we all just make our own - or borrow them !

Good luck anyway.

Cheers

Julian

[Motorcycle mad]

Hi Jon
Try putting your test bulb in circuit at the solenoid, and then run the vehicle down the road to re-create the problem, if the bulb goes on and off you have an electrical problem, its worth ago?

I have had a similar problem on my gearbox, I traced my problem to a dirty fuse and holder, before you pull the box to pieces it is worth cleaning the fuse holder with emery cloth, they are not the best of fuse holders and after 30 years they build up a resistance on the arms of the holder and will pass voltage, but without currant, even the rivets on the fuse box can breakdown, and I have had to tighten them up.
Regards

Ken

[stag8manod]

Hi JC, We are still in the UK, Leave tomorrow afternoon. Holiday over. Long flight home. I don't remember the pin size so I will sent a forum message when we get home.
Cheers Ian A