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First show with the TR yesterday since getting it on the road. Lovely ride out to Ripley Castle  but the o/d became sluggish to engage, instead of an instant switch into o/d , first noticed a slight pause, then each  activation was a longer pause until finally nothing.

As I have a 4.1 diff it does really need the o/d as without it 50mph is pushing 3000 revs, although it didn`t complain and purred along.

I am hoping that it is just the operating arm under the solenoid that has gradually moved on the shaft, but of course I need to take out the seats, carpet and tunnel to investigate.

While I am in there, my mileometer is reading low (did approx 90 miles yesterday but clocked up only 70), but it is a saloon box and overdrive so I know the speedo drive gear is wrong. I have managed to re calibrate the speedo and have it reading correctly at 40mph. The saloon uses an 18 tooth speedo pinion, and the TR an 15 tooth item. I suppose it is too simple just to be able to drop in a 15 tooth pinion and expect it to work, or is it ?.

Ralph

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Sounds like the rubber boot has torn / shredded / perished / moved and is interfering with the operating arm and/or solenoïd.

Much to my dismay, most of our known suppliers will only sell you the boot with the solenoïd as well. I managed to get the boot only from Denis Welch Motors.

james

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29 minutes ago, Ralph Whitaker said:

First show with the TR yesterday since getting it on the road. Lovely ride out to Ripley Castle  but the o/d became sluggish to engage, instead of an instant switch into o/d , first noticed a slight pause, then each  activation was a longer pause until finally nothing.

As I have a 4.1 diff it does really need the o/d as without it 50mph is pushing 3000 revs, although it didn`t complain and purred along.

I am hoping that it is just the operating arm under the solenoid that has gradually moved on the shaft, but of course I need to take out the seats, carpet and tunnel to investigate.

While I am in there, my mileometer is reading low (did approx 90 miles yesterday but clocked up only 70), but it is a saloon box and overdrive so I know the speedo drive gear is wrong. I have managed to re calibrate the speedo and have it reading correctly at 40mph. The saloon uses an 18 tooth speedo pinion, and the TR an 15 tooth item. I suppose it is too simple just to be able to drop in a 15 tooth pinion and expect it to work, or is it ?.

Ralph

If you have a saloon box with J type od that is the normal speedo reading. As you note, the speedo gear drive is a different ration than the A type od. Depending on tyre size the speedo reads almost exactly half your speed in Km/h. E.g. 50 on the speedo is 100 Km/h.

If it is a J type od I had the same symptoms with my TR6 J type od. It turned out the seals on the solenoid operating shaft were worn out and she wouldn't hold pressure after the oil got hot. Worked ok for awhile after start and then would sometimes work and then it would stop working. After cooling overnight it would work for awhile and then give up again.

You can replace the seals on the solenoid but as I didn't know the history of my solenoid and it looked quite old I replaced it. Haven't had an issue with the od since, about 3 years.

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The speedo drive for a TR is through a 2.5:1 reduction, for a saloon box it is 3.5:1  I have the same box, & my fix was to source a speedo from a Triumph 2.5 P.I. Mk2. this has the correct turns per mile (840) a 3.7: back axle, 15" wheels, & 3.5:1 speedo ratio.  The internals of the P.I. speedo fit well into the TR speedo case (yes. really)

Only mods required is to slightly lengthen the slot in the dial for the trip readout, drill a new hole in the case for the trip reset cable, & to use a speedo cable with the correct end to match the thread on the new part.

1888167926_Speedomod3.thumb.JPG.0dc933a0ab5ae951b2667fb77423122f.JPG  1316282324_Speedomod2.thumb.JPG.f50672a170e1cafd4655ed6da6197bc1.JPG

Bob.

Edited by Lebro
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1 hour ago, Ralph Whitaker said:

The saloon uses an 18 tooth speedo pinion, and the TR an 15 tooth item. I suppose it is too simple just to be able to drop in a 15 tooth pinion and expect it to work, or is it ?.

I too have a saloon box with J type OD, rebuilt 'to TR spec' and the speedo reads correctly, so it must be possible though maybe both gears require changing.

Another way to do it is to use one of the speedo-drive gear boxes available from Speedograph Richfield. 

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Yes, both  gears would require changing. My O/D is A type, re-built to TR spec, & rear casing changed to TR type (also Healey 3000).

They did not change the O/P shaft (with gear on) so still saloon ratio.

Bob.

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Thanks for all the replies. I had the O/D in bits to replace the bearings while I was doing the gearbox, and noted that the output shaft has the speedo gear machined on to it, so not easy to swap.

It is an A type overdrive same as Bobs, but I didn`t change the tail housing, instead I used an angle drive unit to get the speedo cable into the right place.

I like the sound of changing the innards for a 2000 unit, equally the speedo drive gearboxes from Speedograph are worth investigating.

I have got the speedo registering quite well, at least at the lower end of the scale, checked at 30 and 40 with my neighbourhood roadside speed camera, haven1t checked the higher ranges yet against the sat nav, so really at the moment it is just the mileometer that niggles me, but if I know it is wrong I can make allowances for now.

Got home early today so whipped the seats, carpets, and tunnel out. With the solenoid removed I could engage and disengage the o/d easily manually, so that`s still working OK, so took the operating lever off and think I found the culprit. As you can see from the pics the clamp end had no space left between the upper and lower sections to allow it to clamp properly on the shaft, so I assume it had been gradually moving with each subsequent operation of the overdrive. I have now rectified it by running a hacksaw down between the 2 halves to get some clamping room back. Also the arms were twisted out of alignment so it was only making contact on the one side.

Ralph

20210601_181452.jpg

20210601_181725.jpg

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13 hours ago, Ralph Whitaker said:

Thanks for all the replies. I had the O/D in bits to replace the bearings while I was doing the gearbox, and noted that the output shaft has the speedo gear machined on to it, so not easy to swap.

It is an A type overdrive same as Bobs, but I didn`t change the tail housing, instead I used an angle drive unit to get the speedo cable into the right place.

I like the sound of changing the innards for a 2000 unit, equally the speedo drive gearboxes from Speedograph are worth investigating.

I have got the speedo registering quite well, at least at the lower end of the scale, checked at 30 and 40 with my neighbourhood roadside speed camera, haven1t checked the higher ranges yet against the sat nav, so really at the moment it is just the mileometer that niggles me, but if I know it is wrong I can make allowances for now.

Got home early today so whipped the seats, carpets, and tunnel out. With the solenoid removed I could engage and disengage the o/d easily manually, so that`s still working OK, so took the operating lever off and think I found the culprit. As you can see from the pics the clamp end had no space left between the upper and lower sections to allow it to clamp properly on the shaft, so I assume it had been gradually moving with each subsequent operation of the overdrive. I have now rectified it by running a hacksaw down between the 2 halves to get some clamping room back. Also the arms were twisted out of alignment so it was only making contact on the one side.

Ralph

20210601_181452.jpg

20210601_181725.jpg

Well done. I haven't seen that one before. I just hope I can remember it when I need to.

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Just been putting it back together and I cannot set it up according to the book, the "setting holes" are supposed to line up when the solenoid is engaged to show the valve is fully open, but mine line up "at rest" with the valve closed and move well past when the O/D engages. The solenoid is working correctly and clicking onto the holding coil, and everything is working running it with the car on stands. I had a similar problem when I initially built the car up, but don`t remember it being so far out.

I have been trying to find an image of the cross shaft to see what is on the valve end that operates the valve rod because I was wondering (dreading) if it was that which was moving on the shaft.

Ralph

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11 hours ago, BlueTR3A-5EKT said:

Have you read the excellent Buckeye Triumph technical article on A type overdrives?

 

https://www.buckeyetriumphs.org/gearbox

 

Peter W

Had a look at this last night, with particular focus on setting the operating lever. Interesting that he says the setting instructions may work for a new o/d, but he has never found a used o/d that will set correctly using the method explained in all the manuals.

Also interesting that the amount of lift controls how sharply the o/d kicks in, too much and it bangs in and shocks the whole system, .016 being about right.

Going to have another look at mine and try to get the lift set correctly at 16 thou.

Ralph

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Gave the TR a run yesterday to check out the O/D.  Changes in fairly well, not with a clunk but a fairly positive action which I can only liken to an automatic gearbox changing up, but coming out of overdrive is not so positive and can take a couple of seconds. 

It was only a run of 5 miles so the gearbox oil may not have been up to temperature, and I am still on the Morris AG90 gear oil, but still, it does not seem to be working as positively as it was before. I am now concerned that one of the oilways may be obstructed.

Any thoughts?

Ralph.

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1 hour ago, Ralph Whitaker said:

Gave the TR a run yesterday to check out the O/D.  Changes in fairly well, not with a clunk but a fairly positive action which I can only liken to an automatic gearbox changing up, but coming out of overdrive is not so positive and can take a couple of seconds. 

It was only a run of 5 miles so the gearbox oil may not have been up to temperature, and I am still on the Morris AG90 gear oil, but still, it does not seem to be working as positively as it was before. I am now concerned that one of the oilways may be obstructed.

Any thoughts?

Ralph.

I wouldn't get too concerned Ralph. If it is going in and out use it for a few months and see what happens. It is highly unlikely that an internal oil way is obstructed, possible but after 45 years with these cars in the TR register it isn't one I've encountered yet.

I'm not familiar with the oil you are using but I use Castrol VMX 80 and have used it in all my TRs for years. It is great and the od works very well on all of them. Too heavy a grade can affect the engaging and disengaging so if your oil is a heavy one it might be worth changing it.

Another problem with heavy oil is it doesn't flow as well. I had a garage do an oil change on my daily driver car many years ago. They used hypoid diff oil. The gearbox failed some time later and it was put down by the rebuilders as the oil not flowing around the bushes as well as it needed to.

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3 hours ago, John McCormack said:

I wouldn't get too concerned Ralph. If it is going in and out use it for a few months and see what happens. It is highly unlikely that an internal oil way is obstructed, possible but after 45 years with these cars in the TR register it isn't one I've encountered yet.

I'm not familiar with the oil you are using but I use Castrol VMX 80 and have used it in all my TRs for years. It is great and the od works very well on all of them. Too heavy a grade can affect the engaging and disengaging so if your oil is a heavy one it might be worth changing it.

Another problem with heavy oil is it doesn't flow as well. I had a garage do an oil change on my daily driver car many years ago. They used hypoid diff oil. The gearbox failed some time later and it was put down by the rebuilders as the oil not flowing around the bushes as well as it needed to.

Morris AG 90 (or All Gear 90 to give it the full title) is specifically for classic gearboxes and contains no EP additives. I was going to change it for Penrite GB40 that a lot over here use, but then when others came on and said they had been using all sorts of 80 and 90 weight oils for years without problems I decided to leave it.

Ralph

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I was recommended by a rebuilder, and so use Morris straight 40, have for a number of years now.

I get what you say about all the differing advice, but there is a concencus that a 40 weight is kinder to the O/D.

I'm with John here though, I think its time to get the summer out of the car, with a working O/D, and if its still a niggle

have a look on one of the Grey days we will be having in a few months time.

John.

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11 hours ago, John Morrison said:

I was recommended by a rebuilder, and so use Morris straight 40, have for a number of years now.

I get what you say about all the differing advice, but there is a concencus that a 40 weight is kinder to the O/D.

I'm with John here though, I think its time to get the summer out of the car, with a working O/D, and if its still a niggle

have a look on one of the Grey days we will be having in a few months time.

John.

I agree, I don`t want it in bits again now the sun is shining ( between the rain). 

Ralph

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On 6/7/2021 at 6:48 PM, Ralph Whitaker said:

I agree, I don`t want it in bits again now the sun is shining ( between the rain). 

Ralph

I'm using Sae30, mainly because that's what it said in the manual. I must admit that the gearbox used to be a liitle difficult until warm when I first got it (25 years plus ago). On changing to Sae30 the gear change was a lot easier so I guess it was some what thicker originally. I've just put the engine and gearbox back in a few weeks ago and found that setting the overdrive up was a little trial and error. As you stated the system in the book doesn't work (or didn't for me). I actually ended up with it engaging but not disengaging. So had to back it off a little. Now it seems to be right but I do notice that the going in is far less "violent". An auto changing gear is a great description. 

      If it's slow to disengage due to the oil thickness you could take it on a long test drive and get it nice and warm and see if it makes a difference. You then will know if a change in oil would help. I must admit the more I read the more I think I should be going thicker than the Sae30 I'm using. 

Neil

Edited by NCS_TR3A
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I gave the car a good run on Saturday evening and the O/D seems to be working fine again now, especially when fully warmed up. Mine is a b---er to get into second when cold, but becomes considerably easier when the oil gets hot and thins out, so I suspect the thicker oil is preventing the syncro rings doing their job. I think I am going to change to a 40 weight oil, as I feel that it will ease the gearchange and probably help the o/d too.

Ralph.

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13 hours ago, Ralph Whitaker said:

 

I gave the car a good run on Saturday evening and the O/D seems to be working fine again now, especially when fully warmed up. Mine is a b---er to get into second when cold, but becomes considerably easier when the oil gets hot and thins out, so I suspect the thicker oil is preventing the syncro rings doing their job. I think I am going to change to a 40 weight oil, as I feel that it will ease the gearchange and probably help the o/d too.

Ralph.

Ralph, 

    Thats exactly what mine was like before I changed the oil at the first service. Ie the pig to get into 2nd until warm. All gears were a little harder but 2nd was the pig. I have no idea what was in it but suspect it was 90 grade. The only issue with going thinner would be the risk of oil leaks. 40 does seem to be the preferred "thin" oil. 

  Glad to hear its working though and I guess you can live with it until you have time etc. 

Neil

 

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22 hours ago, ianc said:

And 2nd to O/D 2nd when climbing hills - fills that gap beautifully!

Ian Cornish

If only!.  Mine is a saloon box and only works on 3rd and 4th. Do use it on 3rd though when accelerating away then change into top o/d.

Ralph.

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