This entry with a lot
of inputs from Randall
Austin- Healey 3000
have an A-type Laycock-Denormanville overdrive. Same ratio as the TR
TR
2/3/A/B/4/A/5/250/early 6 all used A-types.
The change to J-type didn't occur until around 1974 or 75 (IMO as a cost
reduction measure). It should be possible to fit a J-type to a TR3, but I think
it's going to take a lot of modifications. The J-type has the gears, clutches
and mount set further back, so one must modify the transmission tunnel for
clearance, and do something creative with the rear motor mount and the frame
rails, (and shorten the drive shaft). The D-type is for Spitfires.
From: "Power
British Performance Parts, Inc. britcars_at_powerbritish.com
The ball just below
the spring and plunger (under the test plug) seats against the
case<blocking> oil from the accumulator from entering the passage to the
operating pistons. The small spring and plunger above the check ball don't
resist the force of the oil, rather they work with it simply serving to ensure
a positive return of the check ball to it's seat when the overdrive is
disengaged.
When activated, the
solenoid raises the operating valve forcing the check ball off it's seat (and
against the small spring and plunger) allowing pressurized oil from the
accumulator around the ball and entering the passages to the operating
pistons. When de-activated, the valve
drops down and the check ball seals off the oil from the accumulator. The valve
drops further than the check ball exposing the hollow end of the valve. The force from the cone-clutch springs
pushes back against the operating pistons forcing the oil from the operating
piston chambers back through the exposed hollow part of the valve and out a small
drain in the bottom of the valve back into the overdrive sump.
I agree with Randall
that the o-ring accumulators seem like a better design from a sealing
standpoint, but keep in mind that there are an awful lot of compression rings
on the earlier version. By carefully staggering all the end gaps, you can still
affect a very good seal such that the accumulator will hold pressure for days
on end.
Tony chose not to
remove his accumulator and it held from a Sunday afternoon all day Monday to
Tuesday morning when I disconnected the gauge with just about 100 PSI still
showing. On my rebuilds, I usually let
them sit overnight after a break in run with the gauge connected and it's not
uncommon to have them read between 350 to 400 PSI the next day. I suspect that
if Brian had the plunger and spring installed, his readings would be very
similar to Tony's.
I also agree with
Randall that its a moot point as the unit will build up normal pressure in the
time it takes you to back out of the driveway (the pump doesn't care which way
the mainshaft is turning) and accelerate up through first gear.
From: "Randall Young" <ryoung_at_navcomtech.com>
It does drive quite normally out of overdrive, it is just
that nothing happens for ages when you engage overdrive, then it is effectively
neutral!
Graham, the thing is that the sprag (unidirectional) clutch should never
let it be "effectively neutral" when driving in the forward
direction. One of it's purposes is to take up the (direct) drive when neither
of the main clutches is engaged, this keeps the engine from speeding up while
the OD is shifting. If your engine is able to speed up when you engage the OD,
then the sprag clutch is not working and, as I said, a teardown is indicated,
separately from whatever the problem is that keeps the overdrive clutch from
engaging (probably low hydraulic pressure).
Subject: RE: Overdrive J Type still from : "Randall Young"
They have supplied a 8 start drive gear and a 20 tooth cog.
Before I install these I would like the general opinion if these are these
correct for whatever the differential ratio fitted to a non-overdrive rigid
axle TR4A. Any opinions?
Should be right. 20/8 = 2.5
which is the speedo drive ratio used by all TRs before about 1973. The speedo
heads were changed according to the original equipment tires and differential
ratio. So assuming your speedo head still matches your diff and tires, all
should be swell.
If I'm coasting
downhill, it'll engage almost immediately and behaves pretty much like I'd expect,
dropping rpm's by a good bit. I think it's *really* engaged, though sometimes
it feels like it's actually "free floating" as if I was still
stepping on the clutch pedal. In any case when I step on the gas, even to
maintain speed, it'll slip out, sort of sliding back up to the *regular* rpm's
again. This makes me think "o/d clutch" though maybe it means
"not enough pressure".
It's marginally
possible it's the clutch, but much more likely it's low oil pressure (possibly
caused by 'correct' valve adjustment, more on that later).
1. is the
click-click-click-click phenomenon a helpful clue, and if so, what does it
mean?
The clicking probably
indicates an electrical problem, most likely a bad connection somewhere. I doubt this is related to your slipping
problem.
2. I haven't removed
and cleaned the filter yet. It looks like I just remove the plug on the bottom,
remove the bolt and filter. Right?
Your OD will most
likely not have the bolt. Otherwise,
you're exactly correct. Note that plug
is also the drain plug, almost all of the oil is going to run out. Might as well pull the gearbox drain plug at
the same time ... although there's only a pint or so still in the gearbox, you
should change it all.
3. anything else I
should do that doesn't require disassembly of parts that are useful for
driving?
If you're serious about
making the OD work, you should probably plan on pulling the trans tunnel, and
leaving it off for awhile.
4. if you had to
guess, what do you think the problem is: o/d clutch, hydraulics, solenoid,
relay, switch, or current or past owner?
My first guess would be
valve adjustment. As has been commented
many times on this list, the 'book' procedure for
setting the operating valve frequently does not work. The simple test
for this problem is operating the lever by hand to see if the OD engages. Unfortunately, since yours partially
engages, it may be tough to tell the difference with the car on jack stands. Perhaps you can find some brave person to
ride with you and push on the lever as you drive up a hill.
The more direct test is
to remove the operating valve plug, and measure how far the valve ball rises
when the solenoid is operated. It
should move at least 1/32". Note that
a healthy solenoid will launch the ball into space, so either put your thumb
over the hole, or lift the solenoid plunger before energizing the
solenoid. Fortunately the ball is a
common size bearing all, I was able to find one at the local hardware store
<g>
Next most likely
culprit is the OD pump anti-return valve.
Check out for more details http://www.team.net/www/healey/tech/big_hly/od/delborder_od.html
If that doesn't solve
the problem, it's time to get a pressure gage. Bill Bolton at Bolt-On Healeys
(see the vendors list)
BTW, the gage doesn't
have to be oil-filled if you are only going to use it a few times then put it
on the shelf. However, the oil-filled
gages cost only a little more, and last far longer in this application. The OD hydraulic pressure pulsates, and the
constant motion will eventually wear out an ordinary gage.
see also the gearbox
section
Randall Young ryoung_at_NAVCOMTECH.COM
First of all, the
problem is not really related to GL4 vs GL5 specification, the GL5 standard
actually has a tougher limit for copper corrosion. The real problem is a
particular additive, used to increase the 'extreme pressure' properties of the
oil, and which conventional GL5 typically has more of (because it has to meet a
higher standard for EP). This additive
is a sulphur compound, which can break down at high temperatures and form sulphuric
acid. The same additive is used in conventional
GL4 oils (at least some of them), just not as much of it. This additive is mostly what gives EP gear
oil it's distinctive smell.
However, the base oil
used for synthetic gear oils naturally has a higher pressure resistance, and so
needs less of the additive. According to Redline, their MTL (which is a GL4
rated gear oil) has none of the additive.
I've noted that the
Valvoline synthetic (which I use in my diff) has very little of the 'gear oil
smell', so I believe it has little, if any, of the sulphur additive, and so
should be safe for use in the gearbox.
However, Ken
Gillanders at BFE has reported problems when using Redline MTL in racing
Triumphs, apparently because it is too slick.
The specific problems reported were slipping out of 3rd gear (under
downhill hard braking), and difficulty shifting into 2nd gear towards the end
of the race.
Both were on freshly
rebuilt boxes.) The first problem was cured just by switching back to motoroil,
the second one required replacing the 2nd gear synchro (which was done
frequently until they switched oil).
Of course, lots of
people use synthetic, including MTL, and have no trouble at all, so your
mileage may definitely vary !
The BMC Service
Workshop Manual warns "It is essential that an approved lubricant be used
when refilling. Trouble may be experiencd if some type of extreme
pressure lubricants are used because the planet gears act as a centrifuge to
separate the additives from the oil." A 90 "weight" gear oil has
a viscosity at the upper point of the range of a SAE 40 engine oil and the
lower point of the range of a SAE 50 engine oil. The workshop manual
recommends either a SAE 40 engine oil or a SAE 20w/50 engine oil in the gearbox
and overdrive unit for operating climates above 41F . I used SAE 30 for years
(over 20) in my gearbox and overdrive with no problems except it was sluggish
when the outside temperature was above 100 F. I finally switched to SAE
20w/50 motor oil and it shifts in and out quite crisply now. A
"detergent" oil contains a variety of additives including anti-rust, anti-foam,
anti-wear, anti-oxidants, dispersants, and detergents. The detergent
& disperant additives keep contaminants (primarily by-products of
combustion) in suspension in minute particles to prevent sludge from forming.
The anti-wear provides an initial startup protection to camshafts and other
heavily loaded bearing surfaces. The benefits of a modern additive engine
oil must be considered before choosing a non-additive straight mineral
oil. There are still some (American Petroleum Institute) API grade SB engines
oils out there which are non-deterent/dispersant but still contain an anti-wear
additive (I have used is a Mobil SAE 30 SB engine oil for break-in oil to seat
new rings in used Porsche 911 Nikasil cylinders which cannot be honed).
Allowing sludge to settle out is true 1930's technology. Drain the oil
every 15,000 or three years and the detergent and dispersant additives will carry
the crud all out into your drain pan.
Pete Cowper - 1960 BT7 (owned 30 years),
From: Roland Wilhelmy
rwil_at_cts.com
My friend and mechanic, who drives and likes
Triumphs, found that once when he put hypoid in a Healey OD/tranny, it would
not shift (would not stay shifted, actually).
When, after a few test miles, he replaced the hypoid with engine oil,
the OD worked the way it should.
From: "Robert
Wiley" wileyrob_at_pacifier.com
I would agree Roland -
I friend of mine purchased some miss marked 30 wt non-detergent oil which
turned out to be gear oil. The o/d
would get stuck in the o/d position and not release. It was only when he drained the oil and we took the o/d apart
that we figured out the problem. We
went ahead and went thru the o/d and gearbox, as everything needed a good
cleaning anyway.
I have used a non-detergent
30 wt oil with a antiwear agent that I pickup while employed with ARCO oil in
the '80's which has worked without a problem for 20 plus years in my BT7 1962
Tri-Carb.
The subject of oil for
OD gearboxes is so controversial that I do not feel like giving any advice. I
am just reporting on other people’s opinion
·
Earl Kagna
< ags_at_shaw.ca
The factory manual definitely specifies the same oil in the engine and trans
o/d - check it out - different weights for different conditions (10 -30, 10 -
40, 20 -50, etc etc). I know many Healey people that use non-detergent in the
gearbox and feel that it does the best job - you have not been mistaken,
although the factory preferred a multi-grade. I don't think anyone is all that
wrong. The key is, whatever you decide to use, keep it topped up, be wary of
additives (because of the cone clutch)
·
“I can
remember sitting in a bar at a meet with Donald himself discussing which oil
was best to use in a Healey. His answer - "use the cheapest and change it often"!”
·
“I have
experimented with all kinds of oils in the gearbox. I wound up using whatever I put in the engine - usually 20/50
-for many years until the discovery of the Red Line, which I found made a
noticeable difference.”
·
"Freese,
Ken" <Ken.Freese_at_Aerojet.com (BJ8)
I recently put in the Redline synthetic oil and am disappointed. The shifts are
actually slower because there seems to be more syncro/gear clashing. The OD
filter drain now also leaks. I will try to fix the OD leak and keep the stuff
in a while longer. If I can't fix the leak, then back to dinosaur oil.
· Oil for the tranny- book says Castrol
GTX. Use 20W50 or something along the
lines of 90W gear oil? I remember
something a while back about additives adversely effecting the synchro cups,
but can't recall what the final determination was.
I use Valvoline Racing 20W50.
None of the EP additive that is said to be dangerous to OD clutches and
brass synchro rings, plus a high level of ZDP ('antiwear' additive, helps
protect against metal to metal contact) and low detergency (detergents are the
main argument against using motor oil in a TR gearbox).
In the Healey world, a
number of people use 30w non-detergent oil in their O/D gearboxes. At Auto
Zone, the only brand they carried was the store generic "Coastal
ND30".( Too cheap to be trusted by me. Francois)
In the triumph world,
for the same overdrive, people seem to use the Valvoline 50w racing oil.
From: "Cory
LeBlanc" <cleblanc_at_midsouth.rr.com>
Try the simplest correction first.
I have fixed this
condition a few times. Remove the tunnel cover and open the brass 7/16 plug
over the overdrive valve. If a teaspoon of oil comes out, this is the problem.
Remove the valve and clear the tiny vent hole that is perpendicular to the
length of the shaft. This hole is tiny, maybe the size of a #60 drill. Do not
reassemble until the 1/8 hole and the #60 hole is clean.
From: "Chris
Dimmock" cd3000_at_bigpond.net.au
This can be a relativeley common occurance. Don't try to drive it in reverse -
and don't park/ drive it anywhere where you can't move forwards. The only way
to get the car to move 'backwards' is by using a trolley jack under the diff -
with both rear wheels off the ground. Out of gear - you won't even be able to
push it backwards.
Jack up the car, secure
it with axle stands, crawl underneath, (or take it somewhere where they will
let you use a hoist) and look at the overdrive. There is a steel plate
sandwiched in between the alloy overdrive housing, around the middle of the
overdrive. Using your copper/lead wire wheel hammer, smack the steel plate
several times. Don't 'belt the living snot out of it' - but tap the steel plate
firmly a few times.
Then go for a drive
& try your overdrive - it should now be released. The overdrive is put 'in'
by the solenoid and hydraulics. It 'comes out' by springs. Sometimes - the
springs have lost tension etc, especially if the car has been standing for a
long time - and won't come out - and sometimes it seems to be related to
temperature - eg this sometimes happens if you drive it hard (eg at a track
day). But this tapping the plate method seems to release the springs from the
plate, and thus deselects overdrive. Everytime I've done this/ seen this done
the problem doesn't reoccur. ie it happened once to me - never since.
Like the SU fuel pump
that stops..... maybe its just the the threat of a copper/lead wire wheel
hammer that intimidates the overdrive back into operation.....
From:
"Graham Stretch" <technical_at_iwnet.screaming.net
I
can't get my J-type OD unit to separate from the transmission. Yes, all the
bolts are out. What am I missing I removed all 8 of the OD Unit to adapter
nuts/bolts.
You
have missed a vital stage of the dismantling procedure that comes before you
touch the first nut in the process of removing the box from the car. You should
have jacked the car up and engaged the overdrive and then dipped the clutch and
disengaged the O/D with no load on it, this releases any tension between the
cone clutch and one way bearing. There are two ways round this now, both
involve bolting the two bits back together. The first and probably easiest is
to refill the box and apply an electric drill to the input shaft engage fourth
gear and energize the solenoid, ensure that the chuck is tight on the shaft or
it could slip which is when you are likely to damage the pilot bearing surface
of the shaft. The other way will work if you have a spare plug to fit near the
solenoid, drill and tap it to accept a grease nipple and then refill your
grease gun (or buy a new one for the job) with hypoid oil attach and pressurize
the system. Both of these methods will release the cone.
How to fit the
overdrive over that bloody pressure pump cam! Article by Mr Finespanner here (pdf, 836K).
From:
Larry Varley varley_at_cosmos.net.au
As an
aside to all this, there is a mistake in the BN1 manual, as it doesn't mention aligning the timing marks on the sun gear pinions outward
when assembling the sun gear into the annulus. I believe this is because
the text was written around the early high percentage overdrive where the
pinions were not stepped and didn't require timing. The experts tell me failing
to time the pinions causes uneven wear in the annulus. Another fascinating fact
- you will always find a molybond like substance in the groove behind the teeth
in the annulus, why?
Because
the annulus acts like a centrifuge and extracts some of the additives from the
oil.
From: "Ronnie
Babbitt" rbtr3a_at_home.com
Tonight I refit my
gearbox and OD back together. I repaired my adapter plate a few weeks ago due
to warpage. The warped adapter was the cause for loosing so much oil. I assumed
the oil loss was the brass plug. I surfaced the plug, machined a nylon gasket
even made a tool to tighten the plug. All this effort was in vane for the real
problem was the adapter plate. I reassembled the unit using Hylomar sealer
instead of the Permatex aviation gasket sealer Which I used the first time. The
aviation gasket sealer may have worked well since I now have a functional
plate, but as a result of all the successful commits that have been posted as
result of using the Hylomar, I decided to follow success.
Now for my test: I decided several week ago I was going to take every effort
possible to prevent having to gut my interior and pull this gearbox again. This
time I built a bench test set up. I
Mounted the gearbox to an engine stand. Mounted a pulley to the rear
flange of the OD. On the base of the
engine stand I mounted an electrical motor (1725 rpm) with a pulley.
Installed a V belt and I can now spin
my gearbox on demand. I machined from brass an adapter to adapt a pressure
gauge to the valve body. That's the
setup now here's the results.
With the motor
spinning the gearbox my gauge measured between
350-400 lbs. With out the OD engaged. With the OD engaged the pressure would
drop to about 200lbs and immediately climb back to the previous pressure. I
purchased a "yellow Jacket" 0-500 lb flutterless gauge for about $10.
I would recommend that you purchase an oil filled gauge instead. It becomes
difficult to read as the pump actuates.
I'm unsure if the pressure should remain when the gearbox comes to a
stop. The pressure slowly drops to about 200lbs then rapidly fall off to 0 lbs.
I allowed the gearbox to spin for about 1 hour during that time I would actuate
the OD in and out. I pleased that the unit seems to work flawlessly so
far.(knock on wood). I'm very pleased that I currently have no leaks, even
under pressure. BTW I following the masses and I have changed
to valvoline 50weight racing oil. I previously had Mobile 1
For whatever reason,
the leak I found most maddening was caused by a cracked OD drain plug
gasket. Not having the correct
replacement on hand, I cut one from ordinary gasket material, which was too
thin, with the result first that the drain plug first bottomed against the
screen retainer screw (mine is a very early unit), and then the threads
bottomed in the casting. After finally making a thick enough drain plug gasket,
the next leak was from a warped adapter plate (apparently caused by some
over-spirited tightening of the long studs when reassembling the OD), and the
leak after that was the shifter shaft seals.
The leak from those seals runs down over the OD, making it appear that
the OD is actually leaking.
Randall
Brian, The thin red
gasket (adapter plate to OD case) came from TRF (acquired some time ago) and
the thicker black gasket was recently bought from VictoriaBritish - part #
2-8605, $1.45. Spec on the material I cut the gasket from is: ROL Gaskets,
Rubberized Fiber, 10" x 26" x 1/32", ROL no: RK1016,
interchangesto: FELP: 3137, VICT: JV127/JV210. made in USA.
The adapter plate to
GBX case gasket was simple paper gasket material and madeup well with Hylomar.
I think there is considerably less chance for plate warping effecting this
joint.
From: "Edward Woods"
Did you prime the pump with grease or vaseline? If not, drop the cover,
remove the plug, and shove some grease up against the pump piston. Did wonders
for the one I was working on. John Esposito gave me the clue
Tom Mason, in
Minneapolis has an excellent video out on rebuilding the overdrive. Tom can be reached
at tommason_at_juno.com The video sells for $20US.
It takes a special
main shaft and adapter plate to convert a standard gearbox to OD. They are available from ORS in the UK. ORS will
also sell you the complete conversion kit, including a rebuilt OD unit, for a
price. ISTR they quoted me about 500# for the kit, less electrics. The price to
convert a non-OD main shaft into an OD main shaft was 65#.
There are apparently
still a fair number of cars to be found in UK junkyards that have an A-type OD
gearbox that will fit the TR2-6. Rimmer Bros and several other UK companies buy
them, recondition them, and sell them in the US.
From: Brian Sanborn
<sanborn_at_net1plus.com>
John Esposito of
Quantum Mechanics offers a newly designed and reinforced adapter plate for the
A-Type. Mine was not warped but the
joint was leaking like a sieve. He
charges $65 for the part... from a UK source I believe. He is also sending me a "hard" UK
sourced layshaft.
From: "Randall
Young" ryoung_at_navcomtech.com
Subject: RE: TR3A
Overdrive
I have a '59 TR3A with
no overdrive.......What do I have to do or add to convert it over to overdrive
? >
Ron, by far the
easiest thing is to find an OD tranny with A-type overdrive from anything from
a post-50K TR3A though a (roughly) 1973 TR6 and drop it in. There are a few minor changes required, but
nothing major.
1. Add relay, wiring, switch on dash.
2. Change speedo cable, reroute (takeoff on
OD is on opposite side)
3. Swap tranny front cover from old
transmission (if new one is 4-synchro)
4. Drill new holes (or elongate existing
ones) in crossmember (4-synchro only)
5. Longer studs, bolts between engine block
and tranny.
6. Install TR3 type throwout bearing
That's all I can think
of ... BTW, some of the UK vendors sell used/rebuilt OD trannys taken from
newer cars, try Rimmer's during their summer "free shipping" offer.
Since virtually all
big Healey were overdrive, one can find a Healey OD more easily than a Triumph.
Therefore It's worth envisaging starting with a Healey base O/D for a TR
gearbox conversion: The Healey overdrive can be used to build a TR unit.
Replace the rear section of the Healey with the proper TR section(from the
brake ring back including gears). The TR overdrive is longer and has different
mount.
http://www.buckeyetriumphs.org/
http://www.team.net/www/healey/tech/big_hly/od/finespanner.html
http://www.team.net/www/healey/tech/big_hly/od/