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Mart O

Couple of problems, 59 TR3A

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Hi, after 8 weeks of mechanical recommissioning, finally got my 3A on the road for a couple of short runs in the sun earlier this week! Far enough to fully warm up, about 10 miles of 40-60mph each trip.

 

Before putting it to bed last year, the overdrive was reliable and smooth. I changed the oil last week. It took about 1.6l of EP90. On my first run the overdrive came in as usual, then became intermittent. Now it doesn't come in at all. I've read the overdrive topics on here, they are a bit beyond my understanding. I don't really know or understand what I've got in the A Type overdrive. Could it be something simple, I will see if the filler plug will take any more, now it has had a few miles, in case of perhaps an airlock affecting the apparent level? Are there any other novice mechanic level things I could do, before I have to take it somewhere for an expert look? I know the dashboard overdrive switch is non-standard, it was wired in by Revingtons about 6 yrs ago, to replace an ugly version that was done in its original restoration in the 80's. I have traced the dash wires to a largish relay housing under centre das, which also has 2 knurled adjusters on the underside, which I don't understand. The wires to that point look sound. Don't know where they go after that!

 

My second problem is a squeaking over bumps and also a bumping sound over road bumps. It all seems to come from RH rear. When I inspected the rear brakes and hubs, the RH damper showed signs of a fluid leak. Could this be the cause of the noises. I will top up the damper anyway, unless experience tells me I'm wasting my time? The dampers are decades old, but fairly low mileage. Surprisingly, it seems to corner happily. It seems to do everything happily. What a lovely willing little fella it is. Love it.

 

I would really welcome any views / advice on these problems, before I take it somewhere for specialist assistance, if needed. I am planning start giving it the use it deserves, including some breaks away, so I want to get the mechanical side sorted and give it some local miles, before I head further afield...!

 

Thanks. Martin

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Martin

 

OVERDRIVE

Turn on ignition but don't start the engine.

Engage 3rd gear, and then flick the overdrive switch.

If you hear a loud click, the problem is mechanical.

No click, and the problem is electrical.

 

Go from there.

 

Based on your other comments, get some friends who know about TR's.

 

Cheers

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Martin

 

OVERDRIVE

Turn on ignition but don't start the engine.

Engage 3rd gear, and then flick the overdrive switch.

If you hear a loud click, the problem is mechanical.

No click, and the problem is electrical.

 

Go from there.

 

Based on your other comments, get some friends who know about TR's.

 

Cheers

In case of my car, the switch on top of the box and the 'notch' inside the box need to 'meet' when you engage the overdrive. That notch can wear down. All I needed to do was turning the case of the switch a little (like turning off the tap in the kitchen) and all was well again. My OD problem was like your: intermittent.

 

This site offers tons of information http://www.buckeyetriumphs.org/?page_id=347

 

Menno

Edited by Menno van Rij 2

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In terms of the rear noise, also check the mounting bolts for the dampers.

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EP 90 is on the thick side, general recommendation is for a 40 grade, or a 20W50 grade oil.

 

Bob.

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Thank you Gents,

 

Paul, no loud click, so that helps narrow it down. I had wondered if changing the oil had stirred up sludge or such like, resulting in some mechanical problem within. I will slowly chase the physical wiring and test the circuits step by step, to see if I can find anything.

 

Menno, thanks, I have seen that site from an earlier thread and it seemed a bit beyond me! I really like the diagnose problems logic diagrams, but I think my knowledge of the overdrive system is dangerously limited. I didnt take the car apart in its earlier renovation, so I don't have the familiarity and want to avoid doing anything which makes matters worse. I'll look at the article again, from the electrical failure perspective. But if it isn't obvious to me, I'm loathe to start taking the transmission tunnel off and fiddling, without more guidance, just in case I make it worse. I'll read it again though, to see if more makes sense.

 

Bob, to keep it simple, I didn't mention I have changed the oil twice, the first time to 20w50, which is when I first experienced the problem. I thought EP 90 may help, it seemed a bit thinner to me(?), but has made no difference.

 

McMuttley, thanks. They looked and felt secure, but I will double check when I go back to it. I didn't put a spanner to them, I jumped to the conclusion the leak could be the source. Thanks.

 

All, thank you for your replies. I am shortly meeting up with the localmTR group and will get their input too. Also see if they can point me to a local firm who might help, if i can't sort it.

 

Back to the garage tomorrow!

 

Regards,

 

Martin

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Hi Martin,

 

To use a 20 50, engine? Oil in a used O/D is a possible mistake, the detergents in there, if that is what you used,

can move sludge.

80 90 is too thick, not for the box but the O/D.

 

Trouble is if you ask ten folk you will likely get eight different answers.

 

For my self I use straight 40sae in the unit.

 

I would think starting from where you are now to get the unit warm with a decent run, drop the oil and replace with something thinner would be wise.

Sure you will get the help you need from you local guys on the electrics,

If a knackered relay is diagnosed I wouldn't bother with the replacement

Manufactured copy of the original,lasts no time in my experience had to replace again and simply used a standard, four pin I think relay.

 

John.

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My opinion. You'll be fine with the 90 grade oil. Check that it was GL4 though. If you put GL5 in then drain it pdq.

Edited by peejay4A

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Hi Martin,

if the 20/50 oil was for an engine then the detergent may cause frothing and put air in your pump/accumulator

 

As John states 10 people will give 8 different answers - I believe it will be nearer 11.

 

90 oil will work, many people use it (and possibly have less leaks). Don't use diff oil or EP oil - a simple 90 GB oil.

I prefer the thinner oils 40 etc. But definitely not 20/50 engine oil.

 

40 grade gearbox oil is apprx 20/50

 

If you do have air in the OD then there are ways of removing it - but that knowledge escaped me.

 

Roger

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http://www.kewengineering.co.uk/Auto_oils/oil_viscosity_explained.htm

 

We need to be careful when talking about oil viscosity grades. SAE engine oil grades and SAE gearbox oil grades are not the same. EP90 is about the same viscosity as SAE 40-50 engine oil grade.

Edited by Malcolm T

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When draining down the gearbox, did you drain the overdrive by removing the large brass 'nut' on the underside, and then clean out the filter which becomes accessible? Use of unsuitable oil may have resulted in frothing and an air lock in the overdrive's pump &/or accumulator - allow draining to take place over a rather longer time and (gently) spin the gearbox at the same time with the rear wheels off the ground.

 

As mentioned above, a loose shock absorber will result in noises from the rear. The hex-head bolts are not easy to access and the use of Allen head bolts can allow one to achieve a much higher torque. If a lot of fretting has occurred, the bolt holes may have been rendered oval, in which case either the steel in the bracket needs to be restored or the mounting holes increased to the next larger size (use of metric might minimise the amount of such increase).

 

Ian Cornish

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Thanks for your replies.

 

It is GL4. Both drain plugs (square and lge brass) were removed to drain box and overdrive. They were drained overnight and about 1.6l added to refill, so seems about right. Filter was cleaned and new fibre washer on brass plug.

 

On my run this morning to buy a replacement relay, the overdrive didn't work, but about 5 miles in, down-hill off the throttle in 4th, it came in once and then, after about 2 seconds, dropped back out again. Not worked since. Have tried the 30A replacement relay (which is under the dash in the dashboard o'drive switch circuit), without success.

 

I read somewhere a small current is required to keep the solenoid engaging overdrive. Could that small current be intermittent, causing the problem. Or could a poor connection in the switch circuit be kidding the overdrive into thinking it has been switched out? My overdrive switch does not look like the originals, and I guess doesn't work the same. It is a longish stalk, flick down to engage, it springs back, overdrive comes in and an amber light is lit on the facia behind the steering wheel, flick the switch down again to disengage, it goes out of overdrive and the amber light goes out. Is that familiar? It suggests a current is required to switch it out of overdrive, so am a bit puzzled why it switches out of its own accord.

 

May turn off the rugby and go through Menno's article again, for inspiration! Was a great morning out on the road though. Makes a great exhaust note when accelerating, and really flies. My original heater has really benefitted from being flushed out. Now hot enough to make my leg uncomfortable, with the squeaky fan on. I was warm enough, top down.

 

Martin

Edited by Mart O

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May turn off the rugby and go through Menno's article again, for inspiration! Was a great morning out on the road though. Makes a great exhaust note when accelerating, and really flies. My original heater has really benefitted from being flushed out. Now hot enough to make my leg uncomfortable, with the squeaky fan on. I was warm enough, top down.

 

Martin

That's better than overhere. It's snowing locally here in Holland. Guess where I live - exactly: under the snow clouds! 2 inches of snow and it hasn't stopped snowing since I opened the curtains at 8 am this morning. Around noon, the snowflakes turned into rain, but now it's snow again!

 

Back on topic: make sure that you try and test one thing at the time. It will take a little longer perhaps, but you'll learn more more about your car when you attack this problem methodically!

 

Menno

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Hi Martin,

 

Non-overdrive TR3/3A gearbox I use EP90 (same a diff)

Overdrive TR3/3A gearbox I use Millers Classic 20/50 engine oil, always.

Good luck with your o/d gearbox.

Bump/noise from rear offside; a) shock absorber mounting bolts loose, B) link unit from shock to spring needs replacing.

 

Pat.

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I read somewhere a small current is required to keep the solenoid engaging overdrive. Could that small current be intermittent, causing the problem. Or could a poor connection in the switch circuit be kidding the overdrive into thinking it has been switched out? My overdrive switch does not look like the originals, and I guess doesn't work the same. It is a longish stalk, flick down to engage, it springs back, overdrive comes in and an amber light is lit on the facia behind the steering wheel, flick the switch down again to disengage, it goes out of overdrive and the amber light goes out. Is that familiar? It suggests a current is required to switch it out of overdrive, so am a bit puzzled why it switches out of its own accord.

 

 

You've described how the Revington logic box works. It's under control of the flick switch but will also cut out the overdrive if you pass through neutral.

 

On the A type overdrive the solenoid has two windings. One draws a heavy current to pull in the solenoid then the other winding takes over with a smaller maintaining current.

 

So you have an intermittent problem caused by either

  • The Revington box is misbehaving.
  • The relay is misbehaving.
  • The solenoid is faulty.
  • One or both of the gearbox inhibit switches are faulty or out of adjustment.
  • You have an intermittent wiring connection somewhere.

 

Out with the multimeter...

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Martin - you have a Personal Message (PM) - if you are not sure what that is, you should have a little red marker by the envelope icon in the top right corner of the screen - if you click on it, you will see any PMs that you have been sent

 

Cheers

 

Rich

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Feeling smug!

 

Overdrive now working smoothly. Electrical fault found in all circuits of one half of the 2009 additional fuse box. There were enough good circuits remaining to relocate the overdrive switch / solenoid circuit. Will replace wiring when it warms up. This site page is really helpful for the novice: http://www.buckeyetriumphs.org/technical/AOD/AOD5/AOD5.htm. Thank you Menno and thanks to Richard from Essex for the phone call.

 

Rear RHS damper was loose. Just about managed to tighten it, not sure if it is tight enough for the long term, I guess the way to go will be Allen key headed bolts, switched to the opposite direction, to enable access. Does anyone know the size I need to order? Topped up damper, no longer squeaks or bumps. just watch to see if it is leaking. Will get both refurbished if it does.

 

That's all the recommissioning jobs done, just the tonneau cover to fit, and need to work out how to carry luggage and a tent, along with my Labrador!

 

Thank you to everyone for responding to my plea for help. Really appreciated.

 

Regards, Martin

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Hello Martin,

 

I had the same problem after work on gearbox and overdrive. Checked everything to no avail. If you still have the problem after trying out all the good advice given above, here is your solution: It is an item called Overdrive Trouble Shooting in the Moss TR2 - 4a parts catalog, page 33 in my issue. I'll copy part of the tekst here.

Block the front wheels and put the rear of the car on axle stands. Carefully loosen the OD operating valve plug. Start the engine with fast tick-over, engage 2nd gear and oil should bleed past the loosened operating valve plug. Any air should also bleed, after which the operating valve plug can be re-tightened. If no oil bleeds out, the pump is inoperative.

The article then goes on about how to remedy that.

 

This bleeding did the trick for me and I have had no more OD problems.

 

Good luck,

Jan Duppen

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Jan,

Thanks. I managed to fix it, it was an electrical circuit fault in my case. It is now working as well as ever. Took it to my local Group meeting yesterday. Went like a dream. I love how you have to think about how to drive it. I'm not sure I really need 7 gears though!

Regards, Martin

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Hi every one 

The difference   between  an EP 90,  gear oil and and SAE40 Engine   is pretty much in the chemistry . The viscosity(thickness) are fairly close at operating  temps , a 20w/50 oil will be thinner at ambient temperature to allow the oil to circulate around the engine  much quick at low temperatures . An SAE40 engine oil will thinner,  at ambient temperatures that an EP 90 at but the viscosity should be similar at operating temps 

EP 90 gear oil are pretty much GL 1-5 performance, , typical a GL5 will have significantly more extreme pressure additive  that a limited slip diff GL1 will have .

There used to be a view that   EP oils caused O/D clutches to slip but i use a 75w/90 gear oil in my rebuilt 3a o/d box and have had no slipping but a good quick engage a ta low temp operation , if you don't  use the car in winter use SAE90 

An engine oil   tends to use anti-wear and ant-scuff additives, put not much extreme pressure additive they can also have friction modifiers in them which doesn't help the O/D clutch   . Engine oils  also have detergents and depressants to clean the engine of combustion material and to hold in suspension till the oil meets the filter..The smell you get from gear oils is the Sulphur Phosph ep additive. I would rater use an ep oil in a gear and o./d ... think of the pump, gears and bearings in an O/D .There was a theory  that EP oils attacked bronze   but these day its very rare. Its also worth remembering that modern O/D clutch material is better that the 50"s material... in short it isnt the oil 

I would check the Relay  then connectors are clean, then the isolator  switchs with a battery and light bulb, then the solenoid  if they are all working   then the check the O/D filter   (big brass nut on the bottom

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