[xk] To O.D. or not to O.D

Hi all,
I was hoping to solicit some advise on O.D. transmissions. I
have a standard 4 speed in my XK-140 as well as a spare tranny with
O.D. fitted from another car. I have never driven a 140 with
either but anticipate having to rebuild both. My question is
whether the O.D. is worth the extra expense, which I’m sure to
incur rebuilding the box with O.D. I have been told by at least
one reputable (name withheld) specialist that the original O.D. for
these cars is not very reliable and probably not worth the cost of
a rebuild. He suggested spending even more for a 5-speed
conversion using non-Jaguar tranny parts (which on principle does
not appeal to me). Any opinions out there one way or the other?
Would love to hear from some 140 folks with original O.D.'s running
out there. Thanks a million.

Regards,

Paul Casarona
Auburn, AL–
Cas
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Hello Cas,
I don’t have a 140, but have a late 150 FHC with a 3.8L engine and O/D. I’m
not much of a mechanical expert, but the Laylock overdrive was used in many
brands of cars, Jags, Triumphs etc., and is still desired by many British
car enthusiast. I would suspect they’re reliable if used properly (read that
cautiously) and not abused. I admit I don’t use mine much, as engagement is
at highway speed, and I don’t take many long trips and usually stay at lower
speeds in the right lane if on freeways. What I do notice between my non
overdrive 150 OTS and the FHC is that with the positive lock rear axle and a
lower rear ratio in the differential in overdrive cars there is considerable
more acceleration in lower gears. A while back in Porter’s XK Gazette
magazine Guy Broad wrote an interesting article on the complications of not
changing the differential gearing when changing over to an overdrive.
Another thought, when I rebuilt the engine in my FHC I had the flywheel
lightened. Now first goes by very quickly, and while fun, I wouldn’t do that
again on an O/D car. I would think it would be a nice addition on a non
overdrive car. An all synchromesh 5 speed certainly would be a pleasure to
drive over the Moss crash box, but as you point out, its a choice between
driving an XK in an original configuration or modernizing it.
Good luck,
Jerry Oliver
Olympia, WA
3- XK150s----- Original Message -----
From: “Cas” unionjackrestorations@earthlink.net
To: xk@jag-lovers.org
Sent: Sunday, January 01, 2006 11:52 AM
Subject: [xk] To O.D. or not to O.D.

Hi all,
I was hoping to solicit some advise on O.D. transmissions. I
have a standard 4 speed in my XK-140 as well as a spare tranny with
O.D. fitted from another car. I have never driven a 140 with
either but anticipate having to rebuild both. My question is
whether the O.D. is worth the extra expense, which I’m sure to
incur rebuilding the box with O.D. I have been told by at least
one reputable (name withheld) specialist that the original O.D. for
these cars is not very reliable and probably not worth the cost of
a rebuild. He suggested spending even more for a 5-speed
conversion using non-Jaguar tranny parts (which on principle does
not appeal to me). Any opinions out there one way or the other?
Would love to hear from some 140 folks with original O.D.'s running
out there. Thanks a million.

Regards,

Paul Casarona
Auburn, AL


Cas
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

If the gearbox/OD is not from another 140, it will not fit the bellhousing
on the 140 without some modifiaction

Gary

Gary and Cas; The 140 and 150 bellhousing etc up to the clutch fork lever
are the same. The 150, however, was hydraulically operated. Of course, the
shift lever plates and shift lever position on models other than the XK140
and 150 are different. There were running changes on both the trans and the
overdrive unit during production and some differences based on engine or
model, but operationally they were the same, with the exception of the
manually operated overdrive unit on some 150-S models. By adding the
appropriate electrical pieces to either the 140 or 150 trans, bellhousing
and overdrive unit, the installation should bolt up.
Jerry Oliver
Olympia, WA----- Original Message -----
From: “Gary Otto” ottoga1@cox.net
To: xk@jag-lovers.org
Sent: Sunday, January 01, 2006 12:46 PM
Subject: Re: [xk] To O.D. or not to O.D.

If the gearbox/OD is not from another 140, it will not fit the bellhousing
on the 140 without some modifiaction

Gary

In reply to a message from Cas sent Sun 1 Jan 2006:

Dear Paul: I respond not as a mechanic but as a driver. I have
a '56 140 dhc with overdrive. It’s GREAT. I engage at about 60
and the revs drop from around 3,000 to about 2,400. Meaning it
drops about 600 rpm. The ride is smoother and quiter than having
the engine reving at 3,000 all the time. You should click it out
when stopping or dropping below around 50. If you leave it in, it
will run ok from a stop light and just kicks in when the revs are
right. Again, just a drivers perspective but the car is more
smooth with engaged than not.–
The original message included these comments:

Would love to hear from some 140 folks with original O.D.'s running
out there. Thanks a million.


Don Hannon
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In reply to a message from Don Hannon sent Mon 2 Jan 2006:

Hi Cas,

My 150 has an automatic, I have owned 5 Healeys with OD. It is the
same unit, the case is a little different. I have found the
Laycock unit to be VERY reliable, and will take a lot of
punishment. I have used them all as one would use a 5th gear, at
less than freeway speeds and find it a pleasure just to use the
switch instead of shifting down, feathering the gas instead of
clutching(getting old and lazy). The Healey OD works both in 3rd
and 4th gear, I assume the Jag OD unit works the same. Only once
have I had to clean a screen in one of the OD units.

Good luck,
Frank
150 DHC S838482–
Jaginabox
Auburn, CA, United States
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In reply to a message from Cas sent Sun 1 Jan 2006:

Paul,
I am overhauling a tranny with OD for my 140 FHC, which is supposed
to be equipped with such, but isn’t at the moment. I am really
excited about getting it done and will post some pics on my website
soon. Personally, I couldn’t imagine driving a Jag without a Moss
box, I love the whine and the fact that it takes practice just to
shift without grinding. I am also envious of the guys/gals who
have ‘‘matching number’’ Jags. My 140 has an early E-type 3.8 and my
wife’s 1954 120 OTS has a 120 engine, but not the original. Its
your Jag and you should do what makes you happy, thats the bottom
line, but I have come to appreciate the ‘‘purist’’ here over the
years, there is something to be said for experiencing a Jag the way
it was built.–
Brian http://www.seassites.com/Jaguars/index.html
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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I had heard a warning, awhile ago, that you must be careful to wire the
solenoids to the proper shift switch, as you don’t want OD to engage while in
reverse or in other lower gears!!
seems to not be good for it
jac vanguilder
xk140fhc
Paul,
I am overhauling a tranny with OD for my 140 FHC, which is supposed
to be equipped with such, but isn’t at the moment. I am really
excited about getting it done and will post some pics on my website
soon. Personally, I couldn’t imagine driving a Jag without a Moss
box,

For those, like me, who haven’t “experienced” driving their XK’s in a (far
too) long time (or maybe, not at all), might I suggest that you check-out
Brian’s “go for a ride” video clip… Having a high-speed connection would
be nice, but even you guys on dial-up ought to check it out… the download
may be long, but “The Ride” is worth it… Of course, Crank Up The
Speakers!!!
Charles #677556.----- Original Message -----
From: “Lannes”

Brian http://www.seassites.com/Jaguars/index.html

In reply to a message from JerrysJaguar sent Sun 1 Jan 2006:

Oh great…
I’ve installed an OD from a 150 into my 140. My concern, after
reading your post, is my diff ratio. My car has a 3.31 and the ODs
came with a 4.09 I believe. I don’t plan on using the OD at speeds
below 60mph or 2500rpm so maybe I won’t have a problem. I can see
where it could cause strain or lugging if it were to be used at
lower speeds, especially without the proper engagement switch which
is activated only in top gear.
Joel–
The original message included these comments:

more acceleration in lower gears. A while back in Porter’s XK Gazette
magazine Guy Broad wrote an interesting article on the complications of not
changing the differential gearing when changing over to an overdrive.


ex jag, '66 E-type S1 4.2, '56 XK140dhc
Denison, TX, United States
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In reply to a message from ex jag sent Tue 3 Jan 2006:

Jac, I have heard the same about the wiring with the OD, don’t
know if its just an �Urban legend� or not, but I plan on having my
friend who is great with wiring take care of it for me… the
electric system isn’t my forte.
Joel, Im thinking you are probably ok. I can remember my father
teaching my older sister how to drive in his new 1957 XK140 FHC,
(with OD) and my sister asking, �Dad, why do I have to use first
gear when it starts out perfectly fine in third gear?�…

Charles, you have to that 120 of yours rolling ! Enjoy that GREAT
engine sound for yourself !–
Brian http://www.seassites.com/Jaguars/index.html
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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Brian;
That’s part of the problem… I remember, very well, the sound of
my 120 DHC… Your video brings back fond, ecstatic memories of a better
time in my life…
And… Ima workin’ on it! ;-} The sounds on your video are a HUGE
encouragement!!
Charles #677556.----- Original Message -----
From: “Lannes”

Charles, you have to that 120 of yours rolling ! Enjoy that GREAT
engine sound for yourself !

Hi Joel,

I hope you have that top gear switch connected to your overdrive solenoid.
If you use the overdrive in lower gears the torque will burn out the
clutches, and if you (try to) use it in reverse you will instantly destroy
the one-way drive.

Mike Eck
New Jersey, USA
www.jaguarclock.com
'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2

I can see> where it could cause strain or lugging if it were to be used at

lower speeds, especially without the proper engagement switch which
is activated only in top gear.
Joel

Joel,
Well, I suppose you can get by with the higher gearing, but you might want
to read that article I mentioned. You won’t get the benefit of the 4:09 rear
though, and of course most 150 OD rear were posi, which helps, I fell, for
stability a high speeds. My 61 XK150 FHC just sits down about 90 MPH in OD
and feels very solid.
On the wiring question that Jack and Lannes mentioned, the top plate should
have a second switch (first for back up lights) for the OD so that with the
relay the OD solenoid is not activated unless in 4th gear. The problem
arises if the switch or the relay becomes defective and activates. If in
reverse, the damage is serious. As a habit, I keep the OD switch off unless
in 4th gear.
Jerry Oliver
Olympia, WA----- Original Message -----
From: “Mike Eck” mikeeck@optonline.net
To: xk@jag-lovers.org
Sent: Wednesday, January 04, 2006 6:28 AM
Subject: Re: [xk] To O.D. or not to O.D.

Hi Joel,

I hope you have that top gear switch connected to your overdrive solenoid.
If you use the overdrive in lower gears the torque will burn out the
clutches, and if you (try to) use it in reverse you will instantly destroy
the one-way drive.

Mike Eck
New Jersey, USA
www.jaguarclock.com
'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2

I can see

where it could cause strain or lugging if it were to be used at
lower speeds, especially without the proper engagement switch which
is activated only in top gear.
Joel

In reply to a message from JerrysJaguar sent Wed 4 Jan 2006:

Hi all
I have connected the OD solenoid so it can only be engaged in top
gear. I am curious though. Is it really necessary to install the
switch on the accelerator if one remembers to take their foot off
the gas before engaging the OD? I know the manual says it’s not
good for it to be activated while under load.
Joel–
The original message included these comments:

On the wiring question that Jack and Lannes mentioned, the top plate should
have a second switch (first for back up lights) for the OD so that with the
relay the OD solenoid is not activated unless in 4th gear. The problem
arises if the switch or the relay becomes defective and activates. If in


ex jag, '66 E-type S1 4.2, '56 XK140dhc
Denison, TX, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

The MK1 and MK2 did not have an accelerator switch.

Mike Eck
New Jersey, USA
www.jaguarclock.com
'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2

In reply to a message from JerrysJaguar sent Wed 4 Jan 2006:

Hi all
I have connected the OD solenoid so it can only be engaged in top
gear. I am curious though. Is it really necessary to install the
switch on the accelerator if one remembers to take their foot off
the gas before engaging the OD? I know the manual says it’s not
good for it to be activated while under load.
Joel

The original message included these comments:

On the wiring question that Jack and Lannes mentioned, the top plate
should

have a second switch (first for back up lights) for the OD so that with
the> > relay the OD solenoid is not activated unless in 4th gear. The problem

arises if the switch or the relay becomes defective and activates. If in


ex jag, '66 E-type S1 4.2, '56 XK140dhc
Denison, TX, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

In reply to a message from JerrysJaguar sent Wed 4 Jan 2006:

Guys,
The top of the 140 OD trans has two switches. Anyone know which is
reverse light and which is 4th gear signal?
Thanks,
Rich–
The original message included these comments:

On the wiring question that Jack and Lannes mentioned, the top plate should
have a second switch (first for back up lights) for the OD so that with the
relay the OD solenoid is not activated unless in 4th gear. The problem
arises if the switch or the relay becomes defective and activates. If in
reverse, the damage is serious. As a habit, I keep the OD switch off unless
in 4th gear.
Jerry Oliver


rich neary
perrineville/new jersey, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

Is it the intent of the throttle switch to act as a step down device…dis engaging the overdrive for better acceleration??

Gary>

From: Mike Eck mikeeck@optonline.net
Date: 2006/01/05 Thu AM 08:44:51 EST
To: xk@jag-lovers.org
Subject: Re: [xk] To O.D. or not to O.D.

The MK1 and MK2 did not have an accelerator switch.

Mike Eck
New Jersey, USA
www.jaguarclock.com
'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2

In reply to a message from JerrysJaguar sent Wed 4 Jan 2006:

Hi all
I have connected the OD solenoid so it can only be engaged in top
gear. I am curious though. Is it really necessary to install the
switch on the accelerator if one remembers to take their foot off
the gas before engaging the OD? I know the manual says it’s not
good for it to be activated while under load.
Joel

The original message included these comments:

On the wiring question that Jack and Lannes mentioned, the top plate
should

have a second switch (first for back up lights) for the OD so that with
the

relay the OD solenoid is not activated unless in 4th gear. The problem
arises if the switch or the relay becomes defective and activates. If in


ex jag, '66 E-type S1 4.2, '56 XK140dhc
Denison, TX, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

The one that closes in reverse is the reverse light switch. The one that closes in 4th is the one for the OD. That’s how I found out. Mt car is at the body shop or I could look at it.

Gary>

From: “rich neary” richneary@aol.com
Date: 2006/01/05 Thu AM 10:00:23 EST
To: xk@jag-lovers.org
Subject: Re: [xk] To O.D. or not to O.D.

In reply to a message from JerrysJaguar sent Wed 4 Jan 2006:

Guys,
The top of the 140 OD trans has two switches. Anyone know which is
reverse light and which is 4th gear signal?
Thanks,
Rich

The original message included these comments:

On the wiring question that Jack and Lannes mentioned, the top plate should
have a second switch (first for back up lights) for the OD so that with the
relay the OD solenoid is not activated unless in 4th gear. The problem
arises if the switch or the relay becomes defective and activates. If in
reverse, the damage is serious. As a habit, I keep the OD switch off unless
in 4th gear.
Jerry Oliver


rich neary
perrineville/new jersey, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

Anyway…I believe the right hand one is reverse and the lefthand one is 4th…>

From: “rich neary” richneary@aol.com
Date: 2006/01/05 Thu AM 10:00:23 EST
To: xk@jag-lovers.org
Subject: Re: [xk] To O.D. or not to O.D.

In reply to a message from JerrysJaguar sent Wed 4 Jan 2006:

Guys,
The top of the 140 OD trans has two switches. Anyone know which is
reverse light and which is 4th gear signal?
Thanks,
Rich

The original message included these comments:

On the wiring question that Jack and Lannes mentioned, the top plate should
have a second switch (first for back up lights) for the OD so that with the
relay the OD solenoid is not activated unless in 4th gear. The problem
arises if the switch or the relay becomes defective and activates. If in
reverse, the damage is serious. As a habit, I keep the OD switch off unless
in 4th gear.
Jerry Oliver


rich neary
perrineville/new jersey, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php