J type Overdrive

[jleyton]

A couple of months ago (shortly after draining a little excess oil fromthe gearbox) whenmy J type overdrive got hot it startedjumping in and out, and then stopped working entirely. All ok again when it cools down and when it is working, it works perfectly.


A suggestion was made to clean the sump filter and the pressure filter. I duly drained the gearbox oil and cleaned the filters which were pretty mucky. Ah ha I thought, cleaning the filters would do the trick. And it did for a very short while until the same problem has reared its head. Rather worryingly, a lot of the muck wasshiny metallic (chrome?) swarf.


Finally I followed Mr Triumph's (to me slightly surprising) advice in the ROM "If gearbox is drained completely, refill with Hypoid 75W Gear Oil" rather than the 80W or 90 recommended for top up - I wonder why they recommend a different one for complete refills?

I'm going to drain and clean again but I'd welcome any thoughts, especially as to where this errant swarf may have come from.

Cheers

Julian

[flying farmer]

imported post

Jumping in and out is usualy an electrical problem, normally in the supply to the solenoid, most often the wires at the bottom of the gearstick break with the constant bending. If it is temperature related it could be the solenoid itself breaking down.It might be worth rigging up an extra wire to the solenoid through an extra switch.When it starts playing up switch on the extra supply and see if the problem goes away

With regards to the metal in the filters, it could have come from anywhere in the gearbox or overdrive. If the bearings are healthy, and the swarf is quite big, do you have a dragging clutch that makes reverse gear crunch. I have seen boxes where a significant amount of the edges of thereverse gear teeth have gone missing with no untoward symptoms.

Otherwise I would suspect impending bearing failure. A generally noisy box in all gears will be the mainshaft or input shaft bearings, these dont normally break up quickly.

If the box is quiet in 4th but noisy in 1st, 2nd, and 3rd it is the layshaft bearings breaking up. These are bright silver needle rollers and when they do go they can disintegrate very quickly and cause a lot of damage.

I would suggest getting the car on the ramps and running it in neutral, there should be no grumbling noises audible (only the input and layshaft bearings turn in neutral) A broomstale or long socket extension stethascope is often useful here, to listen to the different bearings

If no untoward noises are heard I would ignore it for a while longer

Neil

[jleyton]

imported post

Thanks for the comprehensive reply Neil.

The thing is, the gearbox appears to work perfectly, with no extraneous noises of difficulties in selecting gears and, as I mentioned, when theoverdrive is not playing up it works just fine. The bits of swarf were quite small.

As for the electricals, I've come across lots with problems in the loom up the gear lever to the switch as you mention and earlier I rigged up a bypass to this but it wasn't that. Maybe I'll now try down to the solenoid itself as you suggest although I feel that as it's temperature related it is less likely to be electrical?

I really do want to get it sorted as I miss my 6 speed gearbox

Cheers

Julian

[stagmuffin]

imported post

julian i had similar and fitted a new solenoid ,sorted.the seals in the solenoid had swollen and were causing it to do strange things like this .paddocks recon ex/about £50 iirc.test solenoid under car with leads and 12v supply should hear it energise and go in and out as you switch...............steve

[Gresley]

imported post

Hi Julian,

I had exactly this problem once on my 2.5 PI and it turned out to be a corroded bullett connector in the wire to the solenoid under the car - I can't remember if the Stag has these? I have also had a broken wire under the car to the solenoid too so maybe that is worth checking? It gave an intermittent connection as it moved about!

Brian

[jleyton]

imported post

Thanks guys, so I guess I'm going to have to check out the solenoidand wiring.

Of course, the swarf remains a slightly worrying mystery and I couldn't see why it was so temperature related if it was electrical but it could be something like the swollen seal.

Cheers

Julian

[Rubce]

imported post

Hi Julian

I have experienced problems with the overdrive on the GT6. On both occasions it was electrical faults which were easy to correct once I had tracked them down. The biggest job was taking the carpets and transmission cover off which of course you won't have to worry about with the Stag

Hopefully it will be a quick, easy and cheap solution to the problem on your car

Bruce

[jleyton]

imported post

Rubce wrote:

Hi Julian

I have experienced problems with the overdrive on the GT6. On both occasions it was electrical faults which were easy to correct once I had tracked them down. The biggest job was taking the carpets and transmission cover off which of course you won't have to worry about with the Stag

Hopefully it will be a quick, easy and cheap solution to the problem on your car

Bruce

Cheers Bruce,

Mind you, if you saw the conditions I had to work under you'd understand why I wish I could just lift up the transmission tunnel to work on the overdrive :shock: