J-type overdrive oil, fully synthetic?

[Dibnah]

Afternoon All,

I've used Triple QX EP 75w90 Transmission Fluid Fully Synthetic in the Stag MOD gearbox, which is shared with the J-type overdrive. Overdrive was OK for first 200 miles or so, now engaging by itself with the fuse pulled. I suspect that the solenoid is stuck, so at low speed there is not enough pressure to engage the OD, but as speed increases so does pressure, thus engaging the OD.

Another possibility is that the oil is creating the issue, even though the solenoid may be free. Lots of different views on OD oils, has anyone had problems with Triple QX EP 75w90 oil, or problems with other synthetic transmission oil?

[Nick Jones]

I am inclined to go with your solenoid diagnosis.  Possibly a lump of crud in it as synthetic oil may be a bit more detergent and loosened some ancient deposits.  Can be partially dismantled, cleaned and reassembled with new O-rings.

You need to be very careful about going backwards and make sure the OD is disengaged before doing it.  My view is that once released if you go slowly (5mph say) it won't build enough pressure to re-engage but others may differ.  If it does engage while reversing it will burst the one-way clutch, which is bad and to be avoided!

Nick

[Dibnah]

Thanks Nick

Possibly a combination of issues, the OD switch wiring inside the gearstick was damaged, also the switch was not crisp in operation. I have a new toggleswitch strapped temporarily to the side of the gearstick and wiring temporarily run outside the gearstick. The OD now pulls in very quickly, perhaps with too much of a bang (have to use clutch to smooth the change).

The OD is still slow to release when cold / warm, also pulls in when cold / warm with the toggle switch set for out. This improves when the engine / gearbox is hot.

This comparison borrowed from the TR register website compares viscosity of engine oils and gear oils at 100'C. It's possible that the 75W element of the 75W90 oil I'm using isn't viscous enough when cold/warm


I'll change the oil to 80W90 gear oil.

[Nick Jones]

It's possible to dismantle and overhaul the gearstick switch with a bit of care and subtlety and they usually respond well.

J-type ODs can be a little "abrupt" on engagement.  Release issues still sound a bit solenoid related to me.

Nick

[RobPearce]

The combination of release issues with unusually harsh engagement might suggest a blockage in the pressure relief / return plumbing, resulting in abnormally high base pressure (preload). Or a sticky solenoid valve, of course.

[daver clasper]

Hi

Had problems with J type not engaging when switched/not disengaging when switched off, though engaging when disconnected.

After advice from Dave Twigger (Overdrive spares) I cleaned a replaced all o rings in solonoid and o rings in pressure relief valve. Fiddley, though good article by Buck Eye Triumph on net.

Been working fine for 4 years now.

Dave

[GT6 M]

I look at solly o rings first,
ive just had some very funny goings on
Which ODS and ORS says cannot happen,!!!

Im running 85/140 gear oil int OD, it works perfect
comes in v v quick,even at low revs wen cold
and even better wenst hot

M

[Dibnah]

Thanks again for the replies, the car has overwhelmed me with other issues, including losing half the electrics (possibly the ignition switch) and a dragging clutch. I'll resolve both, go for yet another test run and then change the gearbox oil. If that doesn't fix the O/D problem then I'll remove the solenoid

I'll post a separate thread about the clutch.

[OBE]

Just a note on this, ive stuck religiously to a gl4 oil but modern multigrade oils all seem to be gl5 .. whats the opinions on using a modern gl5 oil ?

[Clive]

I would avoid unless compelling evidence that it is OK could be provided.

Comma make a semi-synthetic sx75-90 GL4 oil. Comes highly recommended by (probably) the best ford type 9 rebuilder. (they require GL4 too)

https://www.amazon.co.uk/Comma-SXGL41L-SX75W-90-GL-4-Semi-Synthetic/dp/B004P24XV6

or available at halfords for rather more....

[Nick Jones]

Redline MT90 is good too.  Available from Opie.

Nick

[Jonny-Jimbo]

Do not use GL5 oil - it contains some detergents that GL4 does not, these are harmful to yellow metals like brass etc. If you use GL5 it will eat your syncro's etc and you may find that your gearbox and O/D fail in quick succession.

[dazzer]

I've always used EP90 but on collecting my rebuilt/uprated later  J type (bigger layshaft bearings) and overdrive (bigger pump) from the Overdrive repair centre Sheffield, I was recommended to use engine oil... I'll let you know how it goes.

[Dibnah]

I've made no changes to the O/D or gearbox but the O/D is now working flawlessly following resurrection of the clutch. Cr@p in the solenoid that has now passed through? More reason for an oil change.

[Hogie]

Quoted from dazzer

I've always used EP90 but on collecting my rebuilt/uprated later  J type (bigger layshaft bearings) and overdrive (bigger pump) from the Overdrive repair centre Sheffield, I was recommended to use engine oil... I'll let you know how it goes.

Hi Dazzer,
             I'm amazed that ORS recommended engine oil.  Most (not all) engine oils contain quite a lot of detergent to keep the internals clean.
This could lead to frothing in a gearbox and cause the OD pump to stop working.

When my OD repairer (Hardy at Leatherhead) recommended engine oil I said I was going to use Penrite GB40 and he said that is the same grade.
So are we talking engine oil or 20/50 or SAE40???

IOt's a mine field out there

Roger

[dazzer]

Hi Roger

I've not filled the unit as yet so I'll check with them again. I always previously used the GL4 EP90 but a layshaft let go and filled the previous OD with swarf. So I grabbed a late J type box that I recovered from a skip with the input shaft rusted solid, swapped out the input from the old box and filled it with EP90 GL5 and it lasted for 4 years of rallying with no ill effects!

Layshaft had started to grumble again so took that box into ORS who have done a beautiful job in rebuilding it. In its defence the 'skip' J type turned out to be one of the stronger later types.

I guess I was just lucky.

I'll report back on the oil recommendation.

Dazzer

[Ridgetone Triumph]

I'm guessing engine oil will still work ok???

I once filled the gearbox and diff in one of my MK1 2000's with automatic transmission fluid,  though a little noisy in the gear departments, it certainly helped with acceleration, being less friction!
Don't know how it would have been long term, I only used the car around town and no long journeys.
The race car ran with a thinner gear oil in the O/D box and had no problems.

[Tim Hunt]

The recommendation in the TR4A Drivers' Handbook was an SAE90EP oil for gearbox/overdrive and back axle for all seasons in the home market. I found this oil gave a sluggish o/d engagement until really warm. Many years ago Pete Cox, who knows a thing or two about gearboxes, recommended I use a straight SAE40 monograde engine oil, which I did successfully for many years. More recently I have settled on Penrite GB40, with which I and my box are very happy.

Tim

[Pete Lewis]

On a J type its good to strip the inner piston out of the solenoid, a small 10mm circlip and knock out the hidden inner piston valve plunger,  yuo need a thin wall 1"af spanner, if youmturn the case you can wreck the solenoid.

ep  oils are generally required due to the tooth design and bearing loads,
Rootes cars use engine oil  as an example
Triumphs especially the small chassis 1 or 3 rail wont last
the big saloon /TR box is far more bullet proofed by design,

the overdrive is designed to run on engine oil but shoild be fine on a 80/90ep and was accepted
by laycock and triumph

pete

[Hogie]

Just to throw more spanners in the works.

The 1950's Laycock (overdrive0 service manual shouted from the roof tops DO NOT USE EP oils.
The ingredients could get baked by the cone clutch and leave solid particles in the system and block the odd oilway or two

I appreciate that oils have changed over the years and may not do this.

EP oils are primarily for Hypoid gear types where there is serious sliding of the gear teeth.
This sliding is seriously reduced in a helical gear to a point where it can be ignored (almost !!).

Oils are designed for applications. So if somebody like Penrite say this is a gearbox/OD oil then that is it for me

Roger (Tin hat on)

[RobPearce]

Quoted from Hogie

EP oils are primarily for Hypoid gear types where there is serious sliding of the gear teeth.
This sliding is seriously reduced in a helical gear to a point where it can be ignored (almost !!).

Well... the amount of sliding on a helical gear is certainly much less than in a hypoid but it's not negligible. EP gear oil will increase the torque handling capability of the gearbox. Engine oil would be fine in a 2000 or a Herald but I'd be very wary in a GT6.

[Dibnah]

The saga continues, I now have a slipping clutch, almost certainly the O/D clutch rather than the "main" clutch on the flywheel. Doesn't slip when cold, but starts to slip and then grip as the engine / gearbox warms up. Slips whether O/D is in or not, O/D change previously was harsh and needed "main" clutch to smooth, now doesn't need clutch.

Above 70(ish)mph and the slipping stops, I assume because pressure increases. I've changed the synthetic EP75/90 to mineral EP80/90, no real difference, the synthetic oil was fairly grubby when drained, so it's probably been cleaning.

I've ordered a J-type solenoid spanner to get the solenoid off. I'll need to check the roll pins when I work out where they are.

  

[RobPearce]

When you say it slips "whether O/D is in or not", does that mean the engine revs increase without road speed increase when it's in direct 4th? If so, it's almost certainly NOT the OD clutch.

[Clive]

Mine did...
I cheated and used a known good one off a spare gearbox.

[GT6 M]

Sorry , link no longer available

M