TMP gearbox assembly DIY

VictorII

VictorII

Well-Known Member
Joined
4 Feb 2003
Messages
175
Location
Belgium
home.scarlet.be
I have a TMP 2-pinion gearbox (mk II) but it has developed a hole next to the water output. This seems a problem that occurs often as some marinisers used to employ copper based pipework.

I would like to fix this but I am on the European mainland and have no knowledgeable (about TMP) mechanics around here. So I set out to do it myself - apart from the fixing of the hole.

Has anyone taken the TMP apart? I would like to do it with the engine in place by only removing the reduction box. Is this possible? I have the manual but it isn't clear on the topic. From the drawings I can't tell if there are any internal bolts which require the entire gearbox to be taken off (55 kgs!). If I should have to go this way, I'll have to reopen the engine room top and I've only just refurbished it last year, so would only reluctantly go this way.

In the manual is stated that when the bolts are undone, tapping with a felt tipped hammer should take the gearbox and reduction box apart. I have got the bolts off, but there is no movement in the box. How hard should I tap? Does heat help and where should I apply it?

Any advice is much appreciated!!
 
This is from the website;;;;;
diy.htmThamesway Marine Products Ltd

HOME PAGESUBJECT :- D.I.Y. REPAIRS


D.I.Y. REPAIRS.
The TMP Gearbox does not readily lend itself to the D.I.Y enthusiast.
Whilst not complicated it is however heavy and awkward to handle. Being of
a mix of alloy castings and steel studs it is not unusual for the studs to
'grow' into their holes because of the salt water environment. Separation
can require lots of heat, patience, and care to avoid damage to the faces
of the castings.
The gearbox is attached to the engine bell housing by internal nuts thus
one has to remove the gearbox / bell-housing as a unit. In most cases, as
the bellhousing carries the rear engine mounts, the engine has to be
supported.
It is a good idea, if possible, to undo the Output Coupling and Transfer
Shaft nuts whilst the gearbox is still attached to the engine.
You will require a 7/8"A/F socket ( 1/2" drive ) with an outside diameter
of 1.812 max O/D.
In order to disengage the gearbox drive from the engine a rearward
movement of approx 2.0" is required. ( Mercedes installations need about
6.0" unless you undo the studs from the engine backplate. )
Where the gearbox has a SPLINE input no problem should be experienced in
disengagement, however, in the case of the 8 bush input ( Perkins /
Mercedes ) rust can seize the bushes into the fly wheel. When this occurs
the housing 'bounces' as the rubber inserts in the bushes stretches.
A tried and tested solution to this problem is to cut a 2.0" square access
hole in the housing. ( see sketch ) Squirt in WD 40 and use a lever
between the gearbox flange and the flywheel, adjacent to each bush.
A Workshop Manual is available which gives detailed instructions for
repairing the gearbox. yperlink here to order manual.)
GEARBOX ASSEMBLY HINTS AND TIPS.
For re-assembly you will require: -
Direct Drive :-
TM 12090 x 1, Oil Seal (Input)
TM 12020 x 1, Oil Seal (Output)
TM 12470 x 1, Gasket and 'O' Ring Kit
TM 12016 x 1, Neutral Brake Pad
TM 12009 or TM 12773 Oil Filter ( MK II / MK IV)
Reduction Boxes :_
TM 12090 x 1, Oil Seal (Input)
TM 12436 x 1, Oil Seal (Transfer Shaft)
TM 12436 x 1, Oil Seal (Output Shaft)
TM 12470 x 1, Gasket and 'O' Ring Kit
TM 12016 x 1, Neutral Brake Pad
TM 12009 or TM 12773 Oil Filter ( MK II / MK IV )
Check the following for wear: -
AREA. Fig 1
Input Flange / Input Shaft, Oil Seal running diameter.
Oil Pump Pressure plate face, Oil Pump Gears,
Oil Pump Shaft for ovality. Oil Pump body bushes.
Thrust Washer
AREA. Fig 2
Clutch Linings. Note the Ahead Lining tends to wear on the non-active
face. This shows as deep witness marks of the clutch element "gramaphone
groove". The lining may also have sunk into the Clutch element.
Replacement clutch linings now require bonding in place.
Check the Square section Sealing Ring.
Area. Fig 3
Planet Gear Bushes and Shafts. Excess wear causes noise and loss of oil
pressure.
Check Bearing TM 12021 ref 3.18 ( MK II ).
Check faces of casting for distortion after removal / replacement of
bearings
Area. Fig 4/5.
Check Oil Seal spacer (TM 12410) for wear on running area.
Clear water drain holes of any blockage.
DO NOT OVERTIGHTEN NUTS, THE THREADS IN THE ALUMINIUM CASINGS ARE EASILY
STRIPPED.
Repair stripped threads with Helicoil thread inserts.
We are happy to answer your questions if you experience problems.

---------------------------------------------------------------------
If all you are doing is a repair to the case near the water fittings, I would leave in place and make a fireglass repair over the hole. There is a void behind the case you can see which would normally fill with water, so you should be able to do an "automotive-type repair, then drill it for a new fitting. The guys at Thamesway Marine Products are very helpful over the WEB
 
I am just about to remove my raw water inlet/outlet connections and phoned TMP this morning to discuss the best way. Apparently some are made of aluminium and some are Zinc whereby they act as an anode as well ( the chaps at TMP don't approve of this as they fall appart !). They only sell replacments in Ali.

To get 'em out the best way is to cut off the stub about 5mm clear of the housing and then with a hawsaw blade cut into the connector '' down the length of the pipe'', apparently it doesnt matter to much if you cut into the threads in the housing a bit. It is a bit of a slow job but if you make 2 cuts you can then easily remove a secton of the stub and then ease the remaining part out.

I have to say I hope I dont find any holes around my water connectors !! If I do I suspect I will do a repair with some epoxy metal !

Good luck

Regards Nick
 
out of interest, of the guys who had corrosion problems or gobbled anodes, were your engines isolated (negative connection to separate bolt on starter motor and alternator) or were they "live" and using the chassis of starter and alternator as negative connection? Mine is isolated, 1978 perkins 4108, and still in one piece in spite of the copper piping, .......... so far.
 
Thanks for the info. I'll try heat and if unsuccessful repair in site.

On the subject of engine acting as negative, AFAIK there is no difference as far as galvanic corrosion is concerned. The galvanic current flows between dissimilar metals, not between 12V attachment point and ground. If I were you, I'd replace asap before any holes are formed. If I'd known about this problem, I'd have replaced last year when the engine was out.
 
Your normal galvanic, yes - the dissimilar metals in saline liquid create the battery. I was talking about when there is an introduced current by leakages from the ships battery to metallic bits that shouldn't really be connected to it.
 
the Perky 4108 was marinized by"Duffield" of Norwich & in thier wisdom & experence used copper pipes in the cooling system coupled with a gearbox made from Ali castings.
They had infact designed & made a "Battery" .Tossers /forums/images/graemlins/mad.gif /forums/images/graemlins/mad.gif /forums/images/graemlins/mad.gif
 
I recently had to remove my tmp box having purchased my latest project. When i purchased the boat she had water in the bilges for a number of years and when purchased by me it was within 1/2" of the oil filter opening into the engine!
needless to say this meant the box was virtually submerged.
I removed all the bellhousing bolts(only 3 snapped ! )
The gearbox refused to move so i carefully prised it apart,just enough to drive(gently) two wooden wedges either side.
Leave the wedges in place over night and hopefully like mine it will help ease the rubber drive couplings out,leaving the metal outers behind in the flywheel!
Good luck !
p.s. both the engine and box are salvageable,says something for the engineering of both !!
 
I have a problem with water in gearbox oil. is it possible to remove backplate of water jacket to replace gasket without removing gearbox.
CLABBYDOO.
 
Ref TMP Gearbox

Hi guys thanks for the add. Have a direct drive TMP gearbox with a "water" problem too needing some advice sorry if im hijacking topic I'm getting on and new at this, getting water into my gearbox oil turning it to runny custard is this most likely the water jacket gasket gone or a crack internally in casing or something more sinister and expensive any advice or direction appreciated. Ta.
 
clabbydoo said:
Hi guys thanks for the add. Have a direct drive TMP gearbox with a "water" problem too needing some advice sorry if im hijacking topic I'm getting on and new at this, getting water into my gearbox oil turning it to runny custard is this most likely the water jacket gasket gone or a crack internally in casing or something more sinister and expensive any advice or direction appreciated. Ta.
Click to expand...
see the link in #4
 
TMP say you can run it without coolant if you keep revs below 2000,therefore keeping oil water free.but we are hoping to remove backplate and check for crack,renew gasket,and hope that's it. heres hoping pal.
 
Re: Ref TMP Gearbox

clabbydoo, have been told, if jacket cracked, you can grind it out and repair with epoxy but hopefully wont need to (gasket).
 
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