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Overdrive A type problem


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Hallo everybody,

Solved the problems with the dirt in the gasoline, today beautiful day I did a ride with the TR3A, everything works well, apart from the Overdrive  that does not always enter or comes into operation after a few moments. in 3rd gear always non work. The mechanic checked the oil level of the gearbox.I don't understand if it's an electrical, mechanical or something else problem.I'm waiting for some useful advice, thanks, Marco, Bologna.

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Intermittent or slow operation could just be a dirty filter so it takes time to raise oil pressure. However If the problem only affects third gear it could be the interlock switch that is worn. 

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I had a similar problem with my O/D which was caused by the lever under the solenoid slipping on the operating shaft so it was not fully opening the overdrive valve.

The procedure given in the workshop manual for setting does not always work on older units due to wear, and I found with mine that using the setting hole and a rod would not work. I had to advance the operating lever a fraction  and it works fine now.

Also they seem to work best with SAE30 rather than SAE90 oil, and definately do not use HYPOID oils

Ralph

Edited by Ralph Whitaker
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2 hours ago, Ralph Whitaker said:

I had a similar problem with my O/D which was caused by the lever under the solenoid slipping on the operating shaft so it was not fully opening the overdrive valve.

The procedure given in the workshop manual for setting does not always work on older units due to wear, and I found with mine that using the setting hole and a rod would not work. I had to advance the operating lever a fraction  and it works fine now.

Also they seem to work best with SAE30 rather than SAE90 oil, and definitely do not use HYPOID oils

Ralph

I also had this issue on my TR4. Just a touch further beyond the jigging hole.

 

Roge

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4 hours ago, Roadster64basket said:

Thank you Ralph and Roger...as soon as possible i'll speak with my mechanic...

and i'll inform you about it...

Marco

 

Marco,

Ciao. Se ti vai a vedere nel settore "General Technical", troverai una lista di articoli sotto il titolo: "Bonanza". Me li passano i soci, ed io li aggiungo man mano. Oggi ho aggiunto un articolo sull'A Type Overdrive, che avrà informazioni utili per te. Buona notte,

David

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  • 1 month later...
  • 3 months later...
On 2/21/2022 at 7:13 AM, Ralph Whitaker said:

I had a similar problem with my O/D which was caused by the lever under the solenoid slipping on the operating shaft so it was not fully opening the overdrive valve.

The procedure given in the workshop manual for setting does not always work on older units due to wear, and I found with mine that using the setting hole and a rod would not work. I had to advance the operating lever a fraction  and it works fine now.

Also they seem to work best with SAE30 rather than SAE90 oil, and definately do not use HYPOID oils

Ralph

Hi Ralph , curious about your comment re Hypoid oils , have been using  75w/90 oil for over 25 year with no issues, i am familiar with the formulation of a number of Shell/Castrol and BP gear oil  so interested in your view 

all the best 

Steve

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Hi Steve,

how long is a piece of string.

OD oil is possibly the most contentious question that gets posted.

To start with almost any oil (or soapy water) will make it work - but for how long.

Hypoid oils are very special for the serious loads on/in a Hypoid gear system - eg the diff with hypoid gears.

75W/90 could/is used as a gear oil and has a viscosity of apprx SAE 40. You shouldn't need the EP version as the gears are fairly standard Helix cut teeth.

Laycock in the 50's forbade the use of EP oils as the component parts could 'cook' out with the high temps from the OD clutch and bung up the oil ports.

EP was recommended by Triumph during the 60's/70's - probably to reduce leaking !!!!

My view is that the gearbox is full of gears - so why not use a 'gear oil'   I use Penrite GB40 and not had a problem 

Thus if it works with a 40 grade gear oil then why bother with an EP oil.

 

Tin hat on, duck for cover

 

Roger

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20 hours ago, Nobbysr said:

Hi Ralph , curious about your comment re Hypoid oils , have been using  75w/90 oil for over 25 year with no issues, i am familiar with the formulation of a number of Shell/Castrol and BP gear oil  so interested in your view 

all the best 

Steve

Just going by what Laycock, and now Overdrive Services, reccomend.  I originally put in Hypoy 90,which Triumph themselves advised for the TR4, but then noticed that for the TR2/3 they were recomending Castrol GTX.  After discussions on this site I changed to Morris Oils GB30 and found that the syncromesh worked better and the overdrive operation was sharper.

Ralph

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I use Castrol Manual VMX 80W. I started on this oil to cure cold shifting issues on my MX5 and it fixed the problem. On talking to a friend who is an engineer with Castrol, he said it would be good for the TR. He advised it was much the same as engine oil without some of the additives specific to engines and added a few for gear oil.

I have now used this for about 12 years in my TR3A and filled all the gearboxes I have serviced/repaired. A number of other owners also use it.

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  • 1 month later...
On 2/21/2022 at 7:13 AM, Ralph Whitaker said:

I had a similar problem with my O/D which was caused by the lever under the solenoid slipping on the operating shaft so it was not fully opening the overdrive valve.

The procedure given in the workshop manual for setting does not always work on older units due to wear, and I found with mine that using the setting hole and a rod would not work. I had to advance the operating lever a fraction  and it works fine now.

Also they seem to work best with SAE30 rather than SAE90 oil, and definately do not use HYPOID oils

Ralph

i'm curious why no hypoid oils, have you had issues ???
 

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15 hours ago, Nobbysr said:

i'm curious why no hypoid oils, have you had issues ???
 

Overdrive services at Sheffield do not condone it`s use, or at least oils with EP additives. I am unsure why,, but as they are the experts I bow to their opinion, notwithstanding that Triumph themselves listed it for the TR4 (but not the TR2/3}, although in the lubrication chart in my books they list only "gearbox", and no mention is made of an overdrive.

I know many owners have used Hypoy for years with no problems, and I initially used a 90 weight gearbox oil, but found that it prevented the synchro from working effectively when cold, and changed to a dedicated 30 weight gearbox oil which improved both synchromesh and overdrive operation.

Ralph

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15 hours ago, Nobbysr said:

Also they seem to work best with SAE30 rather than SAE90 oil........... I initially used a 90 weight gearbox oil, but found that it prevented the synchro from working effectively when cold, and changed to a dedicated 30 weight gearbox oil 

Those numbers sound widely different but this is because there are two different standards of SAE ratings - one for engine oil and another for gear oil.

SAE30 to standard J300 (for engine oils) has approximately the same viscosity/temperature range as SAE80 to standard J306 (for gear oils).

Some gear oil producers name their gear oil using the engine oil scale (e.g. Penrite with GB30 gear oil which is quoted as a 20-60 multigrade to J300). The historic reason for this labelling is that car makers used to specify the same oil for both engine and gearbox so the '30' label makes sense when reading the makers handbook. 

 

 

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