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View Full Version : Auto. Trans. Help, please!



Peter in London
04-13-2005, 07:17 AM
I am in despair over my ("55) Speedster's auto. transmission after the transmission fluid started to boil about 170 miles into a complicated weekend excursion last Thursday. The car returned to London on an AA transporter and I continued the weekend on many trains.

History:
Mar.'99 - 72707 miles - Gearbox & Torque converter rebuild by specialists who do Jaguar boxes.
Oct.'03 - Engine rebuild.
Jan. '05 - 84216 miles - Major Auto. Trans, fluid leak. Gaskets replaced.

At some time since the the Rebuild, it started to make a grinding noise and a horrid, rough vibration through the car on changing from intermediate to direct gears, especially when accelerating but almost eliminated by letting up on the gas at just the right moment. This does not happen when everything is cold - only after running a few miles.

The fluid level was fine before my trip (checked according to Shop Manual) and was still only down a fraction when the smell and smoke made me stop - only it is now blackened. I stopped pretty promptly after the problem started, I am sure. It was a fine day and I'd travelled at 50 - 70 mph depending on speed limits with no "hard" driving at all. I was mostly able to avoid the nasty gear change by letting up on the gas peddle but there was one occasion after a hairpin bend on an uphill gradient where I didn't realise that it had changed down to intermediate and it made its nasty grating sound and feel on changing to direct. It was 5 - 10 miles later that I first noticed the hot smell.

What is going on, please? And what can I do about it? The garage that have looked after the car for 10 years say that apart from the black transmission fluid there doesn't seem to be anything wrong (!), but they will change and flush out the old fluid, get it all hot from driving and try to take it to the old chap at the gearbox specialists who remembers something of these old boxes at that stage.

Any advice would be greatly appreciated. I should like to keep the original gearbox (it also has the original engine) and I believe that being 6v. complicates a change to a more modern one in any case. Also I am exhausting my life savings in my retirement!:(

A very sad Peter in London.

N8N
04-13-2005, 08:32 AM
This is just a WAG but you do realize that the torque converter locks up in direct don't you? That sounds an awful lot like the dreaded Ultramatic torque converter shudder, were the clutches in the TC replaced when it was rebuilt? (yes, I know that this is a DG not an Ultra but that's where my experience is.)

Speaking of which, it looks like my old 56J is going to England... if you see a green and primer 56J running around, that's my old car!

nate

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

Roscomacaw
04-13-2005, 11:07 AM
Peter,
Is it wrong for me to assume you have a '55 Shop manual? Consulting my copy, I came down to pages 107 & 108. It talks about the DG tranny overheating in the forward or FWD and R ranges. The causes are either the reverse or low bands dragging.
On those pages, there's lots of diagnostic ideas and remedies. Of course, there's no guarantee that any of these is what plagues your Speedster.:(
Additionally, I just called one of the few guys I know that still works on these DGs. I read him your post and here's a synopsis of what he said to me. Primarily - he feels it's the Torque Convertor that's failed. He said that the vibration and grinding noise you hear is coming from that unit. He also said that probably the primary failure of this sort is a lubrication valve on the end of the mainshaft. This valve twists or fails and the resultant drag is what takes the TC out.
Believe me, Peter - I can't confirm what he says because I AM NOT an automatic tranny guy! I'm only passing on what this fella told me.[V] He did assure me that no simple oil change is gonna cure anything, but even I could have told you that much.:(
BTW, I asked him about rebuilding a DG Torque Convertor and he gets $225 to do it. Right reasonable, to my knowledge! Of course, in your case - the shipping would be a killer:(

Miscreant at large.

Peter in London
04-13-2005, 12:10 PM
I do indeed have the '55 Shop Manual (and the Parts Books) and many years ago I got a copy for the garage as well. We'll go back to it.

Incidentally, I was cruising at about 60 mph and had been for perhaps 10 minutes when the problem occurred, so it would have been in Direct drive. I have in the past cruised all day for two days running at over 70 mph on the French toll roads and it showed no distress. The noise it makes is like a metallic, grating and lasts perhaps half a second or, at worst, one second.

Many thanks for the help. I'll forward the info. so far to Gary at Gary' Shack Motors.

Peter.