Gear Selection Problems

[Guest Neil S]

Afternoon All,

 

I've developed some major gearbox troubles of late. I don't think any previous threads have covered this, so any help would be appreciated ; even my local TR specialist is stumped! Basically, I've been experiencing some gear selection problems intermittently. Sometimes it's fine, other times it's nearly impossible to select any gear. Usually, the problem can be resolved by switching off the motor, giving the clutch a few pumps and generally faffing around with the gear lever.

 

Until recently, this problem was a rare occurence. Recently, I pulled up to some traffic lights, put it in neutral and waited for the lights to change. When they changed I went for first and the bu**er just would not go in. Nor would second, or third, or reverse. After a bit of brutality, it went in and got me home although every gear was a struggle.

 

Once home, I checked clutch fluid etc. and discovered that the car will actually creep forwards in neutral - it's as if a gear is permanently selected and the clutch partially engaged. I drove the car last night and although 2nd was a bit "graunchy", it seems better after not being used for a week. First gear is a struggle to get engaged cleanly and sometimes when it feels engaged, it's not and will graunch when you go to pull away. You have to really shove it in. Second feels as though the synchro is on the way out but I've kind of got used this and adapted to it. Overdrive engages smoothly and quickly.

 

 

Any ideas?

[marvmul]

The only thing I can think of is the needle bearing between input shaft and main shaft : is this is ruined, the input shaft can try to take the the main shaft with it, but it seems rather unlikely.

 

Also, the 1st , 2nd and 3th gear on the main shaft are supposed to spin freely when not engaged : if one of the bearings(bushes)between these gears and main shaft are ruined, they can cause dragging : I suppose this is more likely than a faulty needle bearing between input and mainshaft

[Bald Rick]

Hi Neil

 

This might sound bloody stupid but have you checked the oil level? When I first got my 6 the gearbox was very "notchy" and often difficult to get into gear especially once it had warmed up. When I checked the box, it took well over half a litre of oil.

 

It's a lot smoother now, although I've bought a spare box just in case.

 

Tony

[jonlar]

Hi Neil, I'd agree with Tony's comments, there is obviously some drag being created in the gearbox, and it would be worth draining (pref. whilst hot) the box and refilling with some engine oil. You can check the drained oil for swarf - got to be worth a try!

[Richard Crawley]

Neil

I’ve not heard of a manual car creeping while in neutral before!! Something is obviously very stuck up & I wouldn’t be surprised if you have more than one problem there! Check the oil level as suggested by all means but if that’s OK, I would advise remove the box sooner rather than later; if the lay shaft needle rollers or main shaft bearings are breaking up, it will eventually go ‘bang’ (mine has twice) & if it does, you will not only destroy the lay shaft but a few other gears as well & be left with an even bigger bill! Personally, I'm not sure about using engine oil in the box O/D unit; I have always used old fashoined EP90 GL4 spec & have not had any problems with this for many years but I know some of the more modern EP oils have been reported as eating the brass/bronze components!

 

As I said, it also sounds like you may have more than one problem so I would take the opportunity to check out the clutch (you might as well replace it while you’ve got the box out!), release bearing, cross shaft & fulcrum pin. Lots of previous posts on problems/what to do so check these out & post back if you have any particular problems/questions.

[Guest Neil S]

Afternoon all,

 

and thanks for all the replies. After dropping the car off at my local TR shop, we had the gearbox oil drained and much of the internals came out with it! I think the phrase "Catastrophic Gearbox Failure" can be used here..........

 

If anyone has an A-type 'box they want to sell, let me know!

[Richard Crawley]

Hi Neil

Sorry it was not very good news. The original box was designed for up to the 2 litre 6; BL stretched this to the margins for the 2.5 saloon engine, even more so for the torque that a 2.5 CP 5/6 engine puts out! BL changed the lay shaft design for the Stag as they realised that it could not handle the torque of the V8.

 

If you’re in the business of recon boxes, I would go for a modified box with Stag lay shaft thrust races. I had this mod done 20 years ago after destroying 2 standard boxes due to lay shaft failures & have not had any problems since.