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The overdrive in my 1964 3.8S type (manual) is not working. I can see that there is 12v getting to the unit. The gearbox is full of oil though it was down a fair bit (needed 1 litre).
Any ideas? How much amperage does the solenoid need? How easy is it to remove?. There are two small bolts (maybe 8mm) holding it in place. Is anything involved in removing it other than undoing those two bolts? The car was not used a great deal for several months at one stage and it was during this period that it stopped working. TIA for any advice.
Cheers, Tim
Does your car have a Moss gearbox or an all synchro gearbox? The Moss has the longtail OD & the newer Jaguar box has the Compact Type A. Both are very similar in operation & build. Both same ratio 0.77.
You require to remove the side cover plate next to the solenoid & all will become plain regarding solenoid removal. If the OD is not used for long periods the cone clutch can stick. A sharp blow to the OD casing with a hide hammer at the Black ring/flange will frequently free.
The WS Manual covers operation of the longtail OD from page F17 & the compact Type A from page Fs13.
Far too long to cover here:
Warnings.
1) Amperage draw of solenoid to engage & then drop to hold is very clear & should be monitored or you will burn out the solenoid.
2) Observe measurements with an oil pressure gauge. Crucial!
3) Ensure inhibitor switch is in circuit at all times. Do not reverse the car in overdrive or you will burst the one way roller clutch.
4) Setting the solenoid lever by pin in hole method on offside of gearbox can be extremely inaccurate.
Solenoid is at 90 degrees on compact Type A. This diagram is the longtail with cover plate off. Solenoid slightly tilted up.
Good luck!
This is on a Healey. The solenoid orientation is 90 degrees different to the Jag Type A but otherwise all applies ~ obviously use Jaguar recommended pressures. Rear mounting is different to Jag spring arrangement. He has a series of OD videos.
Might I humbly suggest that before undertaking any drastic mechanical repairs that the car be taken out on the highway and the overdrive given a good "flogging".
The reason for this is that the car was apparently "not used for several months". I have previously found that overdrive units can be very reticent about working if not used for some time.
Perhaps this pertains to the epicycle gears or solenoids getting sticky or something similar. However, a good long run at max speed on a highway with things warmed up and overdrive being selected in and out has sorted out previous problems I have run across.
Bill Mac
MK1
MK2XJ6S3
X300
Previous 14 Jags MK5 to X308
Good idea Bill. The cone clutch gets stuck hence my suggested blow with a hide hammer. Jerking throttle on & off & switching OD in & out during thrashing will also sometimes free it.
It's the typical old Jaguar alternative use for tools. Wheel wrench to clout old SU Fuel pumps with points to get them operational. Centre lock wheels copper/hide hammer for obstinate OD's. etc.
Last edited by Glyn M Ruck; Aug 11, 2021 at 06:29 PM.
The Jaguar MK2 service manual is quite specific about using SAE 30.
However an acquaintance with a MK2 overdrive that kept disengaging when hot, upped his fluid toSAE60(actually straight aviation oil Aero 120 which is the equivalent of SAE60) and that stopped that problem.
Otherwise I would stay with SAE 30. Bill Mac MK1 MK2XJ6S3 X300 Previous 14 Jags MK5 to X308
Thanks Glyn. So would the grade of oil (ie using SAE30 instead of SAE90) affect how the OD would engage (or not)?
I will drain the SAE30 out and refill with 90. Its only been in the box for about 10km thanks goodness.
Oh! Have you got engine oil in there already. Damn ~ it won't have done any damage in 10Km but it creates another issue. You are going to have to do back to back changes until you get any sign of the engine oil out of there. Engine oil additives (mainly Calcium) don't like Sulfur Phosphorus gear oil additives and cause severe foaming/air entrainment in the oil. At the first change you might get oily foam pushing its way out of the gearbox breather. Fortunately we are not talking about high volumes of oil.
Regarding the move to higher viscosity oil. It will push up the common oil pump pressure and improve the chances of engagement/disengagement of the OD. The Jaguar all synchro box requires a dose of EP additive (GL4) for proper wear protection of gears etc.
Just so you understand comparative oil viscosity.
Last edited by Glyn M Ruck; Aug 13, 2021 at 08:10 AM.
ok, replaced the oil and tried the od several times while ignition on but engine not running. I can definitely hear a click everytime its engaged. Will take it for a short drive tomorrow and see if it’s actually working. Its a little hard to go for a drive at the moment cause we are in a reasonably strict lockdown.
Yes ~ you will hear the solenoid click but that does not mean that the OD is engaged ~ you need adequate hydraulic pressure for that. Do not leave it on in that situation for long or you will burn out the solenoid. The solenoid draws 18 to 20 amps to achieve engagement & then drops to a holding current of 1 to 1.5 amps to keep the OD engaged IF engagement has been achieved. (Circuit is under the rear black cover on the solenoid)
Last edited by Glyn M Ruck; Aug 15, 2021 at 09:40 AM.
Wouldbeowner
Hey, don't forget your mask on your test run and do get a vaccination.
I am amazed at photos/videos of Sydney residents getting around in public without masks.
In Qld. wearing masks is mandatory in public spaces, with fines for not complying.
This latest lock down has really "buggered up" our social commitments in the Jaguar and other car club events.
Cheers
Bill Mac
MK1
MK2
XJ6S3
X300
Manual gearbox Overdrive solenoid.
