[xk] Overdrive Disassembly

Does anyone have any experience in taking apart an overdrive that doesn’t
want to come apart?? It is from a Mark 2…and was fitted to a 140.

I’ve loosened the front case nuts and the rear case nuts but neither case
wants to come loose. It doesn’t appear that the problem is with the studs or
stuck mating surfaces, but rather with some internal parts.

Gary

Gary,
Have you removed the drive flange from the rear output shaft? And the
speedometer driven gear from the case?
Greg Bernier>From: “Gary Otto” ottoga1@cox.net

Reply-To: xk@jag-lovers.org
To: xk@jag-lovers.org
Subject: [xk] Overdrive Disassembly
Date: Sun, 1 May 2005 19:23:45 -0500

Does anyone have any experience in taking apart an overdrive that doesn’t
want to come apart?? It is from a Mark 2…and was fitted to a 140.

I’ve loosened the front case nuts and the rear case nuts but neither case
wants to come loose. It doesn’t appear that the problem is with the studs
or
stuck mating surfaces, but rather with some internal parts.

Gary

Yes…I did that…but I was lead to believe that the rear case would come away with the rear shaft/annulus inside it. I’m not sure what force it would take to press the rear shaft forward out of the rear case. The trouble with this thing is that it is basically a cylindrical object and doesn’t have many external surfaces to grab onto. I certainly don’t want to place any levers in the seams and score them up.

It has been suggested that it is “spline locked” or the uni-directional clutch has siezed. I’m wondering if the sliding (two-faced) clutch has somehow become bonded to the annulus.

Gary>

From: “Greg Bernier” gregjag@hotmail.com
Date: 2005/05/02 Mon PM 01:25:02 EDT
To: xk@jag-lovers.org
Subject: RE: [xk] Overdrive Disassembly

Gary,
Have you removed the drive flange from the rear output shaft? And the
speedometer driven gear from the case?
Greg Bernier

From: “Gary Otto” <@Gary_Otto>
Reply-To: xk@jag-lovers.org
To: xk@jag-lovers.org
Subject: [xk] Overdrive Disassembly
Date: Sun, 1 May 2005 19:23:45 -0500

Does anyone have any experience in taking apart an overdrive that doesn’t
want to come apart?? It is from a Mark 2…and was fitted to a 140.

I’ve loosened the front case nuts and the rear case nuts but neither case
wants to come loose. It doesn’t appear that the problem is with the studs
or
stuck mating surfaces, but rather with some internal parts.

Gary

Hello Gary:
Its been a long time since I took aa OD apart.
Did you remove the bottom oil pump, the solenoid mechanical unite on the
side, the speed ometer drive if so I believe it should come apart …
Try using the Jag knock off hammer, it may be just tight.
Have a good day
Manny

Yes…a copper mallet is recommended. I’m waiting for a new THOR as the one
that was with the car is coming apart and may knock me off if I attempt to
use it!!.

I have all the bits off…however the oil pump body requires a special
puller or something else I need to devise (7/16" UNF threads)…but the
manual says it is not necessary to remove it for disassembly as it will just
slip off of the cam it rides on when the case parts. Assembly is a bit
trickier with it in place…but I’ll worry about that later.

Thanks…Gary----- Original Message -----
From: MSHUCARD@aol.com
To: xk@jag-lovers.org
Sent: Monday, May 02, 2005 5:27 PM
Subject: Re: [xk] Overdrive Disassembly

Hello Gary:
Its been a long time since I took aa OD apart.
Did you remove the bottom oil pump, the solenoid mechanical unite on the
side, the speed ometer drive if so I believe it should come apart …
Try using the Jag knock off hammer, it may be just tight.
Have a good day
Manny

My intention was to replace all the seals as it has been sitting 30+ years
and it is the only thing left to rebuild. I’ve found a pretty good source
of parts at www.odspares.com They specialize in Laycock. I have all the
seals…but maybe I’ll be needing more.

Gary

Greg, I hope you don’t live too far from me as I plan to strip down the
overdrive in my S-type.;-)…I suspect that the “O” rings have seen better
days in it but I’m sure I’ll see other problems with it as well when I open
it up…:-/

Gary,
Best wishes with the o.d. rebuild. I rebuilt the one on my Mark IX
myself, too. First time I had ever seen one of those units. I found lots of
brass dust in the oil, from the bushings self-destructing. I was able to
buy a lot of the bearings and internal bushes from XKs Unlimited, and I
also got some of the bearings from a local bearing wholesaler (much
cheaper). The one-way clutch was pretty much toast… the cage was cracked.
I found a used o.d. unit from an Austin-Healy, and was able to swap enough
good parts to finish the job. I did not replace the rings on the
accumulator piston and operating pistons. I would have, if I had been able
to source them. However, the unit performs very well, I have no complaints.
For driving fun, and a feeling of involvement, nothing beats that Moss
4-speed with o.d. The driver is fully in command of the performance, no
slush box slippage and self-induced shifting to take away the potential
performance of the XK engine. Good luck, and have fun doing it.
Greg Bernier Mark IX
792159DN, XK120DHC, XJ6 Ser. III

Chris Burdo, Norwich, CT, USA
1964 3.8S(MOD)OSJR Inspired,1959 XK150 FHC
chris@jag-lovers.org,www.burdospeed.com
Like to chat about Jaguars? Why not try
http://www.jag-lovers.org/chat/chat.html or
http://forums.jag-lovers.org/jchat.html

Be aware that there are some VERY strong springs trying to push the front
and rear halves of the aluminum tailcase apart, so keep the nuts on the
studs for safety. You need to put it in a strong press or use the weight of
a car to hold it together as you take off those nuts.
Rob Reilly - 679187

Thanks…the manual has indicted this. Two of the studs are extra long for the purpose of relieving and applying pressure to the springs. I believe, after some input from an overdrive rebuilder, that the problem may lie in a frozen uni-directional clutch in the center of the annulus.

Gary>

From: “R, J, G & K Reilly” xk120us4@sbcglobal.net
Date: 2005/05/03 Tue AM 08:33:56 EDT
To: “XK mailing list” xk@jag-lovers.org
Subject: [xk] Overdrive Disassembly

Be aware that there are some VERY strong springs trying to push the front
and rear halves of the aluminum tailcase apart, so keep the nuts on the
studs for safety. You need to put it in a strong press or use the weight of
a car to hold it together as you take off those nuts.
Rob Reilly - 679187

In reply to a message from ottoga1@cox.net sent Tue 3 May 2005:

The Laycock-DeNormanville overdrive was also used in Volvos,
and their Haynes manuals have some good pictures, e.g. the
Haynes for 1982-88 740/760 has the Type J and Type P with
photos, cutaway views and a good description of how to get
them apart. It looks like the main gearbox mainshaft should
just pull right out of the unidirectional clutch, nothing
holding it but friction, just take off those 7 bolts holding
the OD to the cast iron main gearbox case, then the whole OD
should come away from it. Its not clear to me how a bad
uniclutch would prevent that. Perhaps careful application of
2 small thin prybars?
These Volvo M41, M46 & M47 boxes look like cousins of our
Jag boxes, I wonder if they were made by Moss, anybody know?
Rob Reilly–
The original message included these comments:

Thanks…the manual has indicted this. Two of the studs are extra long for the purpose of relieving and applying pressure to the springs. I believe, after some input from an overdrive rebuilder, that the problem may lie in a frozen uni-directional clutch in the center of the annulus.


XK120 FHC, Mark V saloon, XJ12L Series III
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

Rob R;
Other than being four speeds and having “basic” similar internal
characteristics, the M-41 Gearbox fitted in the Volvo’s is nothing like the
Moss Box… They were made in Sweden… not by Moss.
The Top Shift Plate on the M-40, 41, 410, etc. has the gear lever
going “inside” to the shift rods… on the Moss box this function is
“external” and at the rear of the Shift Plate.
The M-41, M-410’s are all syncro, easy to rebuild, the gearbox can be
unbolted from the bellhousing, leaving the bellhousing attached to the
engine and can be removed from under the car.
The M-41 is about 12" long (without bellhousing) and 10" tall (still
weighs 70-80 pounds!!) and is a helluva lot easier to “R&R” from the Volvo
without the aid of two gorillas and an elephant. Simply remove the
driveshaft, remove the gear lever (unscrews from the shifter plate,
accessible from inside the car), remove speedo cable and reverse light wire,
four Allen Head “Cap Screws” and withdraw the gearbox… I can completely
remove the M-41 in about thriry minutes.
Charles #677556.----- Original Message -----
From: “Rob Reilly”

These Volvo M41, M46 & M47 boxes look like cousins of our
Jag boxes, I wonder if they were made by Moss, anybody know?
Rob Reilly

The good old days…62 P-1800, 64 122S, 67 122S wagon…

Gary>

From: “BISHOP-13” bishop-13@texican.net
Date: 2005/05/03 Tue PM 02:56:01 EDT
To: xk@jag-lovers.org
Subject: Re: [xk] Overdrive Disassembly

Rob R;
Other than being four speeds and having “basic” similar internal
characteristics, the M-41 Gearbox fitted in the Volvo’s is nothing like the
Moss Box… They were made in Sweden… not by Moss.
The Top Shift Plate on the M-40, 41, 410, etc. has the gear lever
going “inside” to the shift rods… on the Moss box this function is
“external” and at the rear of the Shift Plate.
The M-41, M-410’s are all syncro, easy to rebuild, the gearbox can be
unbolted from the bellhousing, leaving the bellhousing attached to the
engine and can be removed from under the car.
The M-41 is about 12" long (without bellhousing) and 10" tall (still
weighs 70-80 pounds!!) and is a helluva lot easier to “R&R” from the Volvo
without the aid of two gorillas and an elephant. Simply remove the
driveshaft, remove the gear lever (unscrews from the shifter plate,
accessible from inside the car), remove speedo cable and reverse light wire,
four Allen Head “Cap Screws” and withdraw the gearbox… I can completely
remove the M-41 in about thriry minutes.
Charles #677556.

----- Original Message -----
From: “Rob Reilly”

These Volvo M41, M46 & M47 boxes look like cousins of our
Jag boxes, I wonder if they were made by Moss, anybody know?
Rob Reilly

Current days… '62 122S 4dr (29mpg!), '65 122S 2dr, '71 P-1800E (belonged
to my Mother since '75, now is my son’s).
Charles #677556.----- Original Message -----
From: ottoga1@cox.net

The good old days…62 P-1800, 64 122S, 67 122S wagon…

Gary

http://www.jag-lovers.org/v.htm?1115561258

I have posted some pictures of the progress on my overdrive teardown and
reassembly, if anyone is interested.

Gary

In a message dated 5/8/2005 4:39:14 P.M. Eastern Standard Time,
ottoga1@cox.net writes:
http://www.jag-lovers.org/v.htm?1115561258

Hi Gary,
My 150 overdrive is different than yours. I thought that mine being the
early model it would incorporate many parts of the 140 series. The solenoid
housing is totally different & the round stumpy looking thing on the narrow output
shaft housing is where my speedo. drive is located. Did yours have the
original O/D or did you add it on? Why did you have to tear it down, it looks to
be in pretty good shape?

Regards, Otto M.

It and the 3.8 are from a Mark 2. I tore it down because it was an unknown
and I didn’t want to wait until the car was on the road to find out it had
something wrong. The car had been sittting for over 30 years and we are
redoing every last part on the car.

I really have to get it together and mate it to the motor.then deliver them
to the restorers www.classiccoachworksrs.com as he wants to mont as much
as he can to the chassis and then place the body on over them.

Gary

Gary or anyone else that knows,

I am having the same issue with removing the OD from the gearbox. I can get the OD off so far that it is no longer on the locating shoulder but no further. I tried to remive the rear housing but can only get the same movement. You did not put your solution.

Rear drive yoke is off the spline, speedo drive removed, solenoid and spring underneath plate removed.

The rear should slide off with the annulus. The gearbox output shaft must be bound.

Matt

It’s been over 30 years since I did this, but I recall part A24 hangs up on part A42, so you have to remove part A40 and A33 and all that other stuff first.


I also recall springs B3 & 4 are very strong so be careful not to over-stress the flange of the casing. That’s what the long studs are for, letting it off easy.

Thanks Rob, I will remove the check valve and then the oil pump after I make up a pulling tool. I’ll let you know how I get on.

Hi,

I’ve had lots of trouble, but that’s another story and a later compact type “A” OD.

OD Spares and Overdrive Repair Services (Sheffield UK) have both been very helpful. I was able to buy a complete new (NOS) mainshaft for my 4-sp full synchro gearbox also from them for £150 GBP IIRC.

Mine would not come apart as the internal free wheeling clutch mechaninsm had gone ballistic and there were lots of hardened rollers loose inside the whole mechanism and the gears were seriously stuck. It is no rocket science but cleanliness and correct assembly can not be oversterssed. I have had three of these in two different cars and I love them.

Cheers!

1 Like