gearbox removal, clutch replacement and o/d addition

[Dave pb]

Hello.

 

Its been a while since I've been on this forum, but its time to do some work on my gt6.

 

I need to replace the clutch, and so need to remove the gearbox,  and think I might put an overdrive unit it at the same time.  When I drive it now it always seems that 4 gears just aren't enough.  I've recently driven my TR4A down a quite a few motorway miles and overdrive was certainly a great help.

 

So, removing the gearbox - I read its from the inside.  Is that right or is it possible from underneath?

 

And while the box is out, are there any other jobs/modifications that I can usefully carry out?

 

Regards

Dave

====

[Pete Lewis]

the box has to come out from inside the car  , to make access easy steering wheel off (if using the drivers side) and tunnel and seat out

 

if you pick up a OD box then there is totally different chassis mounting plate and support rubber,  shorter propshaft,  the cam on the remote for the od inhibitor switch with a bracket   and if a D type a relay to take 20amps column switch and cowl or hollow gear stick and knob with slide switch.

 

Pete

[Steve C]

And as an addendum to Pete's sage advice, the O/D box is significantly heavier and unwieldy, so have a helper around to help manoeuvre it in place through the interior. On the Herald I remove the passenger sear to give some extra working room, and the lower heater distribution box to allow for more "fiddle room" as I line it up. I would imagine it is even more crowded in a GT6. If the prop shaft connecting bolts end up further back you may also need to get the tin snips out and make up a small cover plate.

 

Regards

 

Steve C

[Pete Lewis]

Many dont take the air distribution box off (H &V) Its only two nuts and a cable clamp , throw in stiff back

stiff knees, and varifocals to make it easier.

 

Certainly needed to get the 6cyl clutch hsg through the apperture

 

its very important you keep the clutch hsg and engine plate gap parallel when refitting by adjusting the engine height old trick is use a peice of timber to make a simple gap sighting gauge, what looks aligned generally isnt.

[Dave pb]

Thanks chaps. Looking out for an overdrive unit - D type.  I assume this is the same one that is advertised for MGBs on ebay etc.?

 

Dave

===

[Pete Lewis]

Theres a range of Dtypes

you need the adaptor casing which is marque dependant, and gearbox dependant.

 

The single rail box was used on spit1500 and midgets1500

 

best to stick with a 3 rail as more parts are available and generally a better box

single rail was a cost reduction box aimed at Marina in the main

 

theres nothing wrong with a J type OD as a normal developement by Laycock

J and D have very different adaptor casings.

As do 3 rail and single rail boxes

 

you can modify your existing box if its okmwith a replacement mainshaft

[Clive]

And to make things clear, you CAN NOT just bolt an OD on the back of your gearbox.

Pete mentions this above, it means a mainshaft swap and adapter plates etc. The easiest route is a complete conversion kit, either reconditioned from Papwort, or the other suppliers (about £1400 exchange I think? plus fitting) or buy secondhand with associated risks......

[Dave pb]

Thanks for the info.    Not cheap then.

 

Dave

====

[AidanT]

Hi. Not cheap by any means no, Mike papworth did mine effectively a fully refurbished box and overdrive. Makes all the difference at speed and its sorted for many years to come

 

Aidan

[PatK]

the box has to come out from inside the car  , to make access easy steering wheel off (if using the drivers side) and tunnel and seat out

 

if you pick up a OD box then there is totally different chassis mounting plate and support rubber,  shorter propshaft,  the cam on the remote for the od inhibitor switch with a bracket   and if a D type a relay to take 20amps column switch and cowl or hollow gear stick and knob with slide switch.

 

Pete

 

Hi Pete, I will have to remove the gearbox from the Vitesse as it's leaking oil badly from the front face where it joins the bell housing. Can the gearbox ( overdrive ) be removed from below? I have access to a two post garage lift and a helper. With my back and hip I don't fancy try ing to lift it out. Thanks. pat

[Clive]

Can't go down as chassis is in the way. Seat out, a couple of bars and really not too bad. You get an alloy bellhousing, helps a lot!

[dave.vitesse]

I bit of background on the gearboxes. The 2 litre Vitesse, GT6 and very early (1972/3) Dolomite 1850 gearboxes are the same, and are three rail close ratio. The Spitfire/Herald three rail is wide ratio but has a different input shaft.

 

The single rail also came in two types close and wide ratio. The wide ratio was used in the Dolomite 1300/1500, Spit 1500 and late Toledo. The close ratio was used on the Dolomite 1850 and four speed TR7. All have more clutch splines than on the three rail. 

 

 Importantly neither single rail gearbox will fit the GT6/Vitesse bellhousing.

 

As interest they were all derived from the (1954) Standard eight. Good old British we can make it do.

 

I concur with all the very sound feedback and, as already been stated, don't try to use the single rail gearbox as there are problems.

 

Just my thoughts.

 

Thanks,

Dave 

[Pete Lewis]

Pat before you jump you need to check the box has not been overfilled

 

the input shaft could be a seal or a scroll you cant tell untill the clutch hsg is off. But a scroll will leak if overfilled,

 

another is the lowest c hsg bolt needs a sealer and copper washer as its a through hole below the oil level

Having a decent gasket on the mating faces is another potential leaker.

 

But as weve all said its take out from inside

 

its best to remove the air distribution box (2 nuts and a cable )

Gives more room to remove .

[dave.vitesse]

the input shaft could be a seal or a scroll you cant tell untill the clutch hsg is off. But a scroll will leak if overfilled,

 

 

Pete - The GT6/Vitesse box has an oil seal in the bellhousing. Of course if the gearbox is coming out its a good idea to change it.

 

You are right lots of people forget about that copper washer, a bit of sealer also helps.

 

Dave 

[PatK]

Can't go down as chassis is in the way. Seat out, a couple of bars and really not too bad. You get an alloy bellhousing, helps a lot!

 

Thanks Clive, by a couple of bars, do you mean " yorkie " bars for strength!?

[PatK]

Pat before you jump you need to check the box has not been overfilled

 

the input shaft could be a seal or a scroll you cant tell untill the clutch hsg is off. But a scroll will leak if overfilled,

 

another is the lowest c hsg bolt needs a sealer and copper washer as its a through hole below the oil level

Having a decent gasket on the mating faces is another potential leaker.

 

But as weve all said its take out from inside

 

its best to remove the air distribution box (2 nuts and a cable )

Gives more room to remove .

Thanks Pete, very good advice as usual. I think that I will take it out and take it up to Mike Papworth as it is also very noisy in 1st, 2nd and 3rd. Then I will do and lie down in a darkened room when i think about the cost!

[Pete Lewis]

I thought he was going to replace the box before handing it over I pretty much condemned it

but understood a replacememt was planned before sale ??

 

When i went out in it sounded decidedly like the mainshaft tip had failed

 

if you go to MP have the 18mm mainshaft and deadicated input shaft or a dolly 1850 input and change the clutch disc to suit.

 

pete

[Clive]

Noisy 1, 2, 3 is usually layshaft pin. Apparently. Replacements, like all gearbox parts, are of variable quality. My gearbox chap much prefers (very) good secondhand but original parts. (think MP does too if quality new are not available, but he has had some stuff made, which is a good thing)

[Pete Lewis]

If you want to trip up to sunny Luton with the gearbox we can have a look and repair most ,

or advise whats wrong before you dive into to deep pocket sydrome

if thats a help

pete

[dave.vitesse]

One thing I did forget was the three springs which are used to load the thrust washer on the lay shaft. These are located in holes, low down, on the gearbox outer face. They are between, wedged?,  the bellhousing and the gearbox. This means when you separate the gearbox from the bellhousing the springs can fall out and get lost.

 

They are not present on the Herald gearbox and were part of the up -grade of the box to take the extra power of the 2 Litre engine.

 

Thanks,

Dave

[Pete Lewis]

you wont find that shown on many parts lists  its 137532    ( its  shown on 1500 spit ) but not identified in other triumph parts books pictorials only the parts listing ,on 6 cyl. 

the springs are a damping device to reduce  unsympathetic  layshaft backlash chatter when idling  has nothing to do with 

the power rating , they were there from day one of the 1600 3 syn box .

just  damps the cluster by loading its thrust washers a bit   and helps with the backlash clatter  you get on many vehicles 

 

old trick was to push the gear stick enough to start baulking , this load quietens down any chatter from the box when idling 

and shows its not a fault noise it just the clatter of all the gear backlashes having a fight  with engine harmonics .

 

Pete

[dave.vitesse]

You are quite right Pete they are on the original 1600 box which in itself is an up-grade on the Herald box. But my understanding at the time, back in the 1960's, was it had more to do with the increase in power. There was quite an increase in torque and this resulted an increase in wear. Hence the chatter. Being a straight six engine harmonics are not normally a problem.

 

Holding the gearstick to stop noises was more to do with the remote. They brought a kit out to reduce this using a nylon washer in the gearstick cup instead of a metal one.

 

Hi Ho those were the days. Keep up the good work.

 

Dave 

[daverclasper]

Hi

 

I had my Vitesse 2 litre box rebuilt by Mike Papworth. He recommended fitting only 1 of the 3 springs (didn't matter which 1) and showed me an old part which had gouges in due to the 3 springs.

 

Seemed odd, but went with it, as he's reputedly an expert.

 

Cheers, Dave 

[dave.vitesse]

I can't comment as I have never hear of this before. I have always refitted the three springs. Sounds interesting though.

 

Dave

[Pete Lewis]

dave stick pressure to identify box clatter has nothing to do with the remote its purely to start the engagement load doent matter if theres a remote or direct stick, or if its truck or car  the baulk ring is just engaged enough to add some load and this damps any backlash clatter,   try it it will all go quieter

all boxes do it some more noticable than others .increasing the idle speed can have similar clatter reducing effects.

 

the springs only pre load the front thrust washer to put a brake on the cluster ,  the fact that the 6 pots a have a crank damper and the 4pots dont is telling the 6 is not as smooth as you think,   and Im sure in later life they were deleted  ( cost saving) but dont have the service notes to back that up  (needs looking up in the HQ library)

 

and Dave C the extra load from the springs must induce more wear than without them , 

 

Ive run with and without with no real conclusion for years .