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MG TD TF 1500 - TD gearbox front and rear oil seal ?

The crankshaft in my TD broke in half so the engine is at the machine shop waiting a new one. The gearbox is sitting on the garage floor and gear oil is coming out of the rear as it sits on the floor. How hard a job is it to remove the seal and replace it with a new one? Thanks in advance for any help. John
John Hambleton

John, see http://www.ttalk.info/gearbox_rear_seal.htm for a 'modern seal' from Jeff Brown. Bud
Bud Krueger

John, here's a technique suggested by Lawrie Alexander a long time ago. I don't Lawrie'll mind if I print it out. I've used it myself.
Bud
***
It is possible to poke the seal into the groove if you are patient and push
from each side as you push outwards from the middle. Obviously, there isn't
room for three screwdrives in there at once, so it is a slow, incremental
task.

Once the seal is actually seated in the groove, we take a deep socket of the
same outside diameter as the part of the rear flange that is to ride inside
the seal. Using a long extension bar and the aid of a screwdriver to get the
seal over the socket, gently work the socket into the seal. Then, from the
other direction, push the socket out with the rear flange so that the latter
is now seated inside the tail housing, inside the felt seal.

After that it is a relatively simple task to slide the tailshaft housing
onto the back of the gearbox, making sure the flange engages with the
mainshaft splines without slipping backwards out of the seal. Then tighten
the flange securing nut and you'll find you do not have seal pinched between
the flange and the guard.

Just be sure all the other parts are inside the tail housing and on the
mainshaft in the correct order before you do this. It's a nuisance to find a
part left on the bench after going to all this trouble to get the seal in
place!

Lawrie
British Sportscar Center
Bud Krueger

The front seal presses into the bell housing.

The rear flange is scrolled to push gear oil back into the gearbox when the shaft is turning. So the problem may not be as bad as it appears. But since the gearbox is out, now's the time to work on it.

Replacing the rear seal is pretty easy. Takes longer to explain than to do. You will need to remove the rear case to replace the felt seal. Take photos as you remove parts.

Remove the speedo drive.

Slide the selectors off of the selector shafts as you remove the rear case. You must lockwire the bolts on the selectors when you reassemble.

Lawrie's method to replace the felt seal works well.

A few years ago, Abingdon Spares sold a white felt seal that was too thick and would not fit into the seat.

The gray seal from Moss fits well. (#121-300) Buy at least two, because you will probably screw up one.

If you can't easily spin the mainshaft after the gearbox is buttoned up, then the felt seal may have "oozed" out and is binding somewhere in the case or the rear flange. Remove the case, throw away the felt seal and use one of the extra seals that your purchased. (This was especially problematic with the white seal from AB)

Definitely check the condition of the rubber mount and support bracket. The bracket often cracks at the corners. It can be welded. The rubber is often deteriorated. Chamfer the corners of the new rubber where they contract the inside corners of the bracket so that the rubber will fully seat into the bracket. Damaged or missing parts are available through the usual suppliers.

Attach the bracket and rubber to the rear case before you install gearbox into the car. It's a kinda difficult to assemble while out of the car. But it's even harder after the box is in the car.

It's not uncommon for the eye in the case that accepts the clevis and fork for the mount to be broken. If so, there are a number of ways to make a do-able fix.

You may want to replace the bearing for the rear mainshaft while the case is open. The bearing guard is probably OK.

Metric high collar lock washers from Bolt Depot --
http://www.boltdepot.com/Metric_high_collar_lock_washers_Alloy_steel_black_oxide_finish.aspx

BSF high collar lock washers from British Tool & Fastener --
http://britishfasteners.com/index.php/washers/steel-washers/washers-for-bsf-bsw-bsc-sizes.html

While you're at it, buy a gasket for the rear case #294-000.

The gasket for the remote that comes in the gasket set was too small in the four or five sets that I have purchased. I photocopied my remote to a PDF file. When I need a new gasket, I print the PDF and use it as a pattern to cut a new gasket with 1/16" gasket paper. Perfect fit every time. I rub oil onto the paper gaskets before I assemble.

Link to the PDF on my Google Drive ...
http://drive.google.com/file/d/0BxisXBEpc-IWUjR0Y1ljVFZOeUU/view?usp=sharing

Download the file by clicking the "download" button ... downward pointing arrow with a bar across the tip. Then print at "full size", "100%", "no scaling."

In spite of my long-winded description, it's a pretty easy fix.

Lonnie
TF7211
LM Cook

You have to remove the rear housing to access the felt seal. I have never tried doing it with the gearbox in the car. It may well be possible. It is held on by four external studs and two on the inside (M8x1mm). The felt seal sits in a recess in the casting and it is very difficult to replace the flange without distorting the seal.
What I do is to fit the seal in the rear of the housing and then fit the flange so the front of the flange is flush with the front of the seal. Tape it up with gaffer tape to hold the position and then slide the rear housing complete with pre-fitted flange onto the gearbox output shaft having fitted a new gasket (greased) beforehand.
You can also fit an external lip seal but this also requires removal of the rear housing. It is much better than the felt seal and acts as a buckle and braces. I made this for my gearbox before I fitted the five speed and it never leaked. Easy to machine if you have access to a small lathe.
I have attached a workshop drawing for anybody wanting to do this.


Declan Burns

A photo.

Regards
Declan

Declan Burns

Above is correct. However, the front is the only one that is actually a true seal. The back felt rides on the spiral cut into the flange (I think- been a while since I have seen one) that screws oil back in to the tranny when it is turning. The oil level is below the rear seal normally. Even if you replace the felt, it will run out if the tranny is sitting on the ground tipped backwards. George
George Butz III

Thanks everyone, leveling the trans on the floor was the fix. The front seal seems to be good no leaks.
Thanks, John
John Hambleton

This thread was discussed between 15/09/2018 and 17/09/2018

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