Speedo Drive

[PhilBell]

Whilst on the speedometer discussion I too have experienced a failure! - I wonder however whether it is the meter itself rather than the drive? Just before the failure a noise was heard which sounded like a spring that was being wound tight and then let go before the noise was repeated.

After about 2 to 3 minutes of this noise which i had no idea where it was coming from apart from the speed side of the bulkhead the noise stopped as did the speedo reading.

I've contacted Speedograph for info on refurbishment which is a reasonable ?55.00 but having read this thread perhaps I'm looking at the wrong end?

A few simple checks before you spend any money:
1. Remove the speedo gauge ? remove under dash trim panel to right of steering column, squeeze your hand in behind the speedo and unscrew the two thumb wheels securing the gauge to the dash. Unscrew the speedo cable connection. Withdraw the gauge (you'll probably need to pull out the various bulb holders first, noting where they go). Insert a match stick in the cable drive hole in the back of the speedo and turn it by hand to see if the pointer moves.
2. See if you can turn the exposed speedo cable end by hand. If you can it may be broken, disengaged from the speedo drive or the speedo drive may be broken.
3. Withdraw the cable by approx 1/2in and try to turn it by hand ? it should rotate smoothly in the sheath. If it doesn't the cable/sheath may be kinked.
4. Withdraw the Cable completely from the sheath to check for breaks ? it should have a square end at the bottom where it engaged with the speedo drive unit on the side of the gearbox.
5. If all of the above check out okay, remove the seats, centre/radio console and transmission tunnel cover (you have to disconnect the handbrake cable in order to pull the handbrake up as high as it will go so that the console will come off without fouling the dashboard). Unscrew the speedo cable sheath from the speedo drive, unscrew the speedo drive from the gearbox, insert your trusty matchstick in the speedo drive and check that the square drive sticking out of the speedo drive turns freely.
6. If all of the above are okay, the problem could be an internal gearbox fault. Fingers crossed it isn't, and it doesn't sound like it from your description.

Best of luck

[richard btype]

Phil - Good concise check list - will report back! Richard

[richard btype]

Phil

Following your procedure I removed the right angle drive to discover that it is the drive that has gone awol. The drive cable is fine as also the speedometer so thank you for the saving!

Now have to make the decision between replacement item from SNG at around 50 or the SR alternative at 90 ish. I believe it was Ray who flagged up the longer male drive in the SR item which must be of help if there were to be wear on the female gearbox socket by spreading the available contact area.

For the local speed cameras It will be a massive help to have this working correctly.

[richard btype]

Phil

"I also discovered that there was no sealant between the glassfibre gearbox cover and the trans tunnel ? no wonder I get a lot of fumes from the oil-onto-exhaust leak. I'll probably use Dum Dum for that so that it's easy to remove in the future"

I'm just awaiting arrival of the new drive unit but wondered what you decided about sealing up the gearbox cover? for reducing nasty fumes from below is a nice idea but not sure how this can be achieved particularly around the opening of the gear stick linkage - or have I missed something?

Richard

[Heuer]

Richard

I used Gaffer tape around the gearbox cover edge because it sticks to almost anything, is the perfect sealant and it can be easily removed. The previous owner had used silicone sealant but it was a huge pain to get off when I needed to get in there. As for the gear stick opening I can find scant evidence Jaguar used anything at all on the early cars (mine has the metal cover, others have a plastic cover). I got fed up with the fumes though so went with Pete and Angus's suggestion and used the silicone rubber gaiter off the S3. It fits almost perfectly but you need to screw it in place and run silicone sealant around the edges (silicone is the one thing Gaffer tape will not stick to ). Details here: http://etypeuk.com/forum/viewtopic.php?t=4798

While you are at it put some 2" thick foam under the gearbox metal/plastic cover to reduce noise and heat. It was standard on the 4.2's so no harm availing yourself of the technology! This is the 4.2 cover and you can see it has the later shape and gaiter. The foam is described as "BD27833 Sound Insulating Pad (polyurethane) between gearbox cover and top of gearbox"

[richard btype]

David

Have just ordered these parts, and having the part numbers has made it an easy process - a very worth while modification that should make all the difference.

Thank you

Richard

[rfs1957]

My 3.8 came with this steel cover and a rubber gaiter. If you say the 3.8 never had a gaiter, David, then the cover must be from a 4.2 - but would the cover fit the 3.8/Moss without modification ? This one looked to be out of the box. Well, until I got at it. The BD27500 gaiter from SNGB (listed 4.2) was a perfect replacement.



However, I thought the 4.2 sealing ring was fitted from below whereas this one had the ring on the top - and it definitely wouldn't go inside, nor would the screw holes have worked "wrong-way-up".



Regarding fitting, whilst tweaking everything for the JT5 we got a vastly better fit all round of the steel cover with judicious use of the blue-tipped multiple-adjuster-tool, the occasional quench, a dolly and hammer (mate seen here in foaling-mode) plus the substitution of M6 threaded rivet inserts instead of the self-tappers.



Is that foam pad worth the money or will anything do - how hot does it get there ?

[Mark Gordon]

Definitely use the foam pad. It seems that everyone who complains of heat coming from around the tunnel has neglected to install the pad. My car has the standard heat shields and the pad, but no upgraded insulation in terms of Coolmat, Dynamat or anything else. The ONLY heat ingress that I notice is a slight amount around the handbrake lever and that is not enough to affect cabin temperature.

[kingzetts]

Dependng on how fond you are of gearbox noise, you may also consider additional sound deadening.

I have standard-ish thick-hardura-type noise deadening mat glued on top of the transmission tunnel and gearbox cover, on top of a layer of Koolmat directly on the metal. I have no problems with radio console fit or with dropping down the centre instrument panel but still wanted to get more noise reduction.

So I recently lined the inside of my centre tunnel console with a sheet of lead/foam sandwich from Noisekillers. It was thin enough that it did not interfere with the radio console fit by raising the centre console unit too high, and it cut down very significantly on gearbox noise. Worth a try (although not if you are building a lightweight - that stuff is quite heavy).

[rfs1957]

Definitely aiming for that John, have now got 10mm minimum clearance everywhere around the JT5 and am going to line the whole tunnel and bell-housing area before reassembly.

My question regarding the foam was whether you can cut/shut your own without fear of it being degraded by the heat ........... didn't Peter C reckon m'cycle seat-foam would do the job ?!

We use dense black closed-cell foam for most applications (on whose edges, incidentally, you can get a fantastic smooth/neat finish by using really coarse sand-paper, by hand) but I don't know how it reacts to heat.

[Heuer]

Jaguar specified polyurethane foam so any low density flexible upholstery foam of 2" thickness will do the job. It will not be degraded by heat up to 135C although exposure to light can cause problems.

As for the gearbox cover it is from a 4.2 however the 3.8 Spare Parts Catalogue says the original cover succeeds to the later version:

3.8


4.2

[rfs1957]

Looks like the first 4.2's had no rubber gaiter either then, or is it listed elsewhere ?

[PhilBell]

Phil

"I also discovered that there was no sealant between the glassfibre gearbox cover and the trans tunnel ? no wonder I get a lot of fumes from the oil-onto-exhaust leak. I'll probably use Dum Dum for that so that it's easy to remove in the future"

I'm just awaiting arrival of the new drive unit but wondered what you decided about sealing up the gearbox cover? for reducing nasty fumes from below is a nice idea but not sure how this can be achieved particularly around the opening of the gear stick linkage - or have I missed something?

Richard

Richard

I followed David's gaffer tape advice but I didn't notice much difference to the cabin fumes afterwards. With two days to go before Le Mans I spotted his tip about adapting an S3 gearlever gaiter, so once gain I removed the interior for access and will have to fit it on Weds night as I'm working this evening. 7.00am Portsmouth Ferry on Thurs! Wish me luck.

[Heuer]

Phil

Put some 2" foam in there as well to reduce heat ingress. You can buy the stuff from any upholstery place or somewhere like Dunelm Mill: http://www.dunelm-mill.com/shop/foam-block-49969

[andrewh]

further to my post in General it would appear that my angle drive has failed and having just got the car back from the trimmers I am less than keen to strip out all the centre console etc etc

Can anyone tell me for sure whether the angle drive can be removed from underneath on a 3.8 Moss box car please?

[Heuer]

You may be able to do it but it will involve a bit of work. You need to remove the exhaust system, the gearbox support bracket and loosen the engine stabiliser completely. You then may be able to reach up and undo the speedo gear knurled sleeve whilst levering the gearbox over to the side using a crow bar. If not you could try releasing the prop shaft u/j to give more flexibility. Removing the centre console does not really help because although you can reach in, the tunnel metal work still prevents you getting the drive off. The two large rubber stoppered holes are in the wrong place to help. You may need to cut a new hole in the tunnel metalwork for access. Either that or remove the engine!

[andrewh]

what? you mean you cannot remove the angle drive without dropping the gearbox/engine? Surely not ? Must be room to remove the drive, I am sure I have read others have managed it without resorting to Engine removal. if it comes down to that I shall be driving without a speedo me thinks

[Heuer]

Couldn't get mine off when investigating a leak. Turns out it was from the rear gearbox seal so the engine/box had to come out anyway. You can remove it on the 4.2 IIRC. No speedo = MOT fail and a prosecution if a passing Police car notices it is not working.

Give it a try and let us know how you get on. All those bits plus the centre console will have to be removed anyway if you have to drop the engine. Just a matter of seeing how far you have to go. Are you sure it is not the cable? Put the end in a drill and see if the speedo turns.

[andrewh]

ok, well I think this is going to have to go on hold for a while as I have not got a lift here and even if I get the car on axle stands its a major amount of crawling around underneath. what a shame. presumably one can unfasten the cable from the angle drive from underneath at least?

[Heuer]

Yes, you can get the drive cable off from underneath but if you don't have a lift/pit it will not be fun. Taking the interior out is not that bad.

Remove seat squabs and remove retaining nuts and set seats to one side
Remove indicator strip and radio console
Remove rear seat belt anchorage bolts and any other retaining screws
Remove gear knob
Remove split pin on rear handbrake mechanism
Lift off centre console
Remove gearbox cover

This is what you are up against (no pun intended):


Even if you undo the knurled collar the speedo gear will only move out fractionally before hitting the tunnel.