Jump to content

Graham (Overdrive not engaging)


Recommended Posts

Hi Graham, welcome to our forum.

Dipstick says it is an early sidescreen box, if it is Tr, you need to look at the boss on the gearbox where the clutch slave cylinder cross shaft exits, for a number for confirmation here.

Re overdrive not operating, first check the gearbox oil level.

 

John.

Link to post
Share on other sites

Hi Graham,

you say you can hear the relay coming with a click (in front of your knees).

But, can you hear the solenoid coming in with CLICK by your left hip.

If you can't hear the solenoid then you either have a duff solenoid or dodgy wiring

You may be luck and have an inspection/access hole in the tunnel to see the solenoid (you may still need to remove the 'H' dash support)

You can power the solenoid direct from the battery with a fly lead to test it.

 

If the solenoid is coming in then you may need to adjust the travel.   Have you got a Workshop Manual? this explains all.

 

Roger

 

Link to post
Share on other sites

Graham

This may be a long shot but I experienced the same problem earlier this year.  Having tried all the usual "fixes" I had it looked at by an auto electrician.  To cut a long story short the problem turned out to be dirty connections at the back of the ammeter.  If I remember correctly power was reduced as a result and despite occasionally working the usual result was a click but no engagement.  The ammeter was removed, terminals cleaned and reconnected resulting in no further problems.

As stated this may not be a "normal" problem but it would be a cheap and simple option before embarking on a more expensive solution.  Worth a try?

Bob

Link to post
Share on other sites

Graham 

All the above advice is excellent. If oil levels are correct, most overdrive problems are electrical.

As Roger says, check if the solenoid is operating when you switch the OD on - there should be a lighter less obvious click which is the relay operating, followed immediately by a more obvious click as the solenoid operates - it is sometimes not easy to distinguish between the two.

You really need to visually see the solenoid plunger working on the side of the OD to be certain its working - this assumes your OD is a TR spec one - just to be clear, it is an A type OD I presume?

If you can see the plunger moving and operating the lever  which connects to a shaft going into the OD casing, make sure the clamp which holds all this together is tight and the shaft isn't slipping. If you can see all this happening, then you need to adjust the clearances as per the manual but be aware that over time the clearances can change so the easiest thing to do is to take tunnel off, jack up the car level and securely, run it in overdrive and move the lever manually to see if you can get the OD to engage - if none of this works then it's probably a gearbox out job and strip down.

If the solenoid isn't responding to engagement, do as Roger says and try a direct supply to it to see if it works - if it doesn't, then hopefully that's your problem and new solenoids are readily available. If it does work, and work well with a clear and good operation ( use a decent sized cable direct off the battery as the solenoid can take quite a lot of current ), then you know you have an electrical issue somewhere along the line - just because a relay clicks, it doesn't mean to say it will always work in providing sufficient current to the solenoid.

Given the fact that it sounds like you  have a TR3, maybe an even earlier gearbox in your car ( the gearbox filler is your clue), then I do wonder what the rest of your set up is, as earlier boxes to your 4A would have had a spring clutch whereas your 4A would have started life with a diaphragm clutch - all of these bits are interchangeable if you use the correct compatible parts, which I assume is the case as your car has presumably been working OK up to this point . But it does point to the fact that have a mixture of bits and pieces which is why I wanted to check that it is an A type - I'm sure it probably is. If you can get the gearbox number which is normally stamped on the ridge above the raised rectangular bit on the LH  vertical side of the gearbox and likewise the OD number which normally on a plate riveted to the OD it may help. Any chance of any photos?

Sorry for such a long response, but if want more info, feel free to send me a personal message and I can send you my contact details and we can have a chat about it all

Cheers  Rich

Edited by rcreweread
spelling mistake
Link to post
Share on other sites

Missed quote

 

Edited by ChrisR-4A
No quote
Link to post
Share on other sites
3 hours ago, Bobble said:

Graham

This may be a long shot but I experienced the same problem earlier this year.  Having tried all the usual "fixes" I had it looked at by an auto electrician.  To cut a long story short the problem turned out to be dirty connections at the back of the ammeter.  If I remember correctly power was reduced as a result and despite occasionally working the usual result was a click but no engagement.  The ammeter was removed, terminals cleaned and reconnected resulting in no further problems.

As stated this may not be a "normal" problem but it would be a cheap and simple option before embarking on a more expensive solution.  Worth a try?

Bob

I had the same problem a few years ago, would engage initially but drop out when headlights or electric fan was on. Ammeter not passing enough current.

Chris

Link to post
Share on other sites
  • TorontoTim changed the title to Graham (Overdrive not engaging)

Hi Graham

I had this problem some time ago, the O/D suddenly stop working. l trailed through the forum for advice after trying several checks including including taking the gear box tunnel out to check the solenoid and wiring etc someone suggested checking the 2 bullet connector located near the main beam switch, bingo one side had come apart, l must have dislodge it with my shoe, reconnecting solved the problem l wish l had seen this feed earlier.

Worth a check. Andy 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.