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Overdrive problem

tjt77
Wise Man
Wise Man
Posts: 525
Joined: Wed Mar 23, 2016 7:01 pm

Re: Overdrive problem

Post by tjt77 »

As Rob states he has a 2 1/2 litre V8 , which utilizes the jaguar "all synchro' gearbox.. therefore recommended oil is indeed EP 90.
look to cause and effect :- if the overdrive was working before oil change and filter service, the first check would be to se that oil level is correct .. it takes some time for the oil to each its level in overdrive as it runs through passages between box and overdrive and can take some time to do so.... so check again that oil runs out of the level plug.. and top off as required..
the most common issue, if everything else is 'good', is crud build up in operating valve .. causing the ball or its plunger to stick.. over the years it can gum up in there . First test ( after assuring oil level is sufficient) would be to remove the little cover plate and test to see if the shaft that operates the lever form solenoid is travelling full distance and pushing the lever to operating valve all the way .. ( its a bit tight with gearbox in car as its close to gearbox tunnel .. and requires good light source to see .. a 3/16" drill can be utilized to check alignment through the holes if its moving its full distance.) its unlikely this adjustment will 'go out' without interferance... but any resistance on the operating rod will throw it off . next check would be to remove the plug that holds the actual valve and remove it to check for cleanliness .. it should all be squeaky clean and isa common place for oil to thicken and solidify over the years .. there is a spring and small plunger below the actual ball bearing that acts as the value to open the oil passage to engage overdrive when depressed by its plunger .. be caerful not to loose any of the parts .. and cleanliness is absolutely essential for these parts .. one small grit particle will render it inoperative.. good luck.

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Alpine Daimler
Posts: 189
Joined: Thu Feb 18, 2016 2:17 pm
Location: A tad west of Hamburg on the Elbe River

Re: Overdrive problem

Post by Alpine Daimler »

Hello again everyone.

Its working again!

I think Christopher Storey probobly nailed it and wins a big fat cigar or similar, why? quick read on....

I eventually found the time last Saturday to perform the checks I mentioned and were recommended, oil level ok, solenoid adjustment satisfactory and the operating valve, ball, plunger and spring were removed and examined, all ok and spotlessly clean but a devil to reinstall correctly with oil dribbling out at the same time! The car was on four ramps and not on a car lift, uncomfortable after a while.

I then decided to change the the solenoid as I had bought a new one anyway, it was installed and adjusted, quite fiddly but do-able if one has right angled spanners to hold plunger, 9/32" and 1/2" for adjusting nut, the feed cable was too short and had a different connecter, tiresome after a long day but relatively easy to get around. As soon as I turned on the ignition, and gently wacked the port side float chamber to close the float valve and got the 95 octane out of my ear and socks I engaged 4th gear and operated the overdrive stalk, in it went with a real "thwack" instead of merely an audiable click.
It had been a long day and a long bike ride home beckoned so I cleared up and soaked up the anticipation the next 4 days as to whether I had 5 gears again.........when home I stripped down the old solenoid, see pic below, not in very good condition, had been suffering from heat exhaustion by the looks of it and the bakelite base had disintegrated, still not bad when one sees stamped on the side that it was manufactured in "03/68"!!

This morning we got up early and fired up something modern, efficient and from Ingolstadt and made our way to the workshop and got the Daimler, Gordon Setter and luggage compartment full of spares, wood etc ready for an alpine excursion to "Fischbachtal" in the Wilderkaiser National Park near Kitzbühel. A lovely autumnal day out operating the heater and burbling around the mountains eventually culminating in operating the O/D stalk and watching the revs sink quickly and appreciably. So, it was indeed the solenoid, thank you Christopher, very coincidental that it's failure occured directly after oil change? The solenoid plunger was very grubby as was the cylinder into which it fits, it was perhaps not getting the full voltage and current sufficient to operate the valve properly?

Thats enough, thanks again, might help someone someday with the same problem........if they read this far!

Regards from Munich

Rob c.
Attachments
Overdrive solenoid.jpg
Daimler inm Wilderkaiser.jpg

Christopher Storey
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Posts: 404
Joined: Wed Mar 16, 2016 6:40 pm
Location: Cheshire

Re: Overdrive problem

Post by Christopher Storey »

Rob : so glad the problem is solved - these electro/hydraulic problems are always a bit frustrating because it can be either electrical or hydraulic or a combination of both !

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