Re: Advice wanted re. TC transmission & rear axle ratio

[CFritz7001@aol.com]

Hello, All,
I'm preparing my '48 TC "Betsy" for a 4-month tour of her homeland. She
has something over 200,000 miles on her original, untouched transmission. My
concern is that the tranny is beginning to be somewhat noisy in top gear,
most especially under light load, constant speed--level ground conditions
(ie. neither accelerating nor coasting / deccelerating). It's not too noisy
when under load or deccelerating in top gear, and reasonably quiet in the
lower gears.
My questions are these:
1. Assuming that an overhaul of the tranny is indicated, which parts are the
most likely to need replacement ?
2. After 46 years as Betsy's chief mechanic, I feel I'm reasonably
proficient as a mechanic, but I have never unbuttoned a tranny. Am I biting
off more than I can chew to attempt an overhaul on my own?
3. I'm seriously considering fitting a lower-ratio rear axle to get more
relaxed cruising. Betsy's engine has been brought up to MK2 TD or TF specs.,
and has an over-bore of 40thou., and she's running 4.50x19" wheels. What
ratio would be the best compromise?
***
Comment, suggestions?
Regards,
Carl Fritz

[Peter Pleitner]

Hi Carl,

I'll address the more or less external parts of the trans you should look at
first. Take the rubber cover off and inspect the rear transmission cover
for cracks while you are there.

As to that noise, it might be that approx. 16 inch long 9/16 inch or so
diameter metal rod that is the remote selector which connects your shift
lever to the transmission. It runs through and is supported by a hole in
two bosses under the remote selector neck made of aluminum. Often these
holes are worn allowing the remote selector rod to rattle. The old fix was
to wrap a shop rag around the remote selector. When I rebuilt mine, I
bushed these bosses and line reamed them, not easy I might add.

The other most likely wear (not destruction points) are the bearings on the
output and lay shafts, the lay shaft itself and shim, shift forks and
selector pin at the end of the remote selector. Almost all of these require
disassembly, not difficult, just puzzling and necessitating some pullers.
200k miles would indicate to me bearing wear is present. But bearing
failure usually announce themselves by a rumble under lead, not a rattle
under no load. Anyway, there is a penny's worth of experience.

Cheers, Peter

-----Original Message-----
From: CFritz7001@aol.com [mailto:CFritz7001@aol.com]
Sent: Wednesday, January 12, 2000 2:37 PM
To: mg-tabc@egroups.com; mg-t@autox.team.net
Subject: [mg-tabc] Advice wanted re. TC transmission & rear axle ratio

Hello, All,
I'm preparing my '48 TC "Betsy" for a 4-month tour of her homeland. She
has something over 200,000 miles on her original, untouched transmission.
My
concern is that the tranny is beginning to be somewhat noisy in top gear,
most especially under light load, constant speed--level ground conditions
(ie. neither accelerating nor coasting / deccelerating). It's not too noisy
when under load or deccelerating in top gear, and reasonably quiet in the
lower gears.
My questions are these:
1. Assuming that an overhaul of the tranny is indicated, which parts are
the
most likely to need replacement ?
2. After 46 years as Betsy's chief mechanic, I feel I'm reasonably
proficient as a mechanic, but I have never unbuttoned a tranny. Am I biting
off more than I can chew to attempt an overhaul on my own?
3. I'm seriously considering fitting a lower-ratio rear axle to get more
relaxed cruising. Betsy's engine has been brought up to MK2 TD or TF
specs.,
and has an over-bore of 40thou., and she's running 4.50x19" wheels. What
ratio would be the best compromise?
***
Comment, suggestions?
Regards,
Carl Fritz

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[Eugene F. Gillam]

Carl,

I don't think you're biting off too much.

I bought a TC to restore and I've tried to do as much as possible myself.
My transmission had been open (and laying on a workbench) for six years
before I bought the car. I managed to tear it down and put it back in
running shape without a whole lot of trouble - and I have much less of a
mechanical background than you do (Navy Electronics Technician for 30
years).

The only part I had trouble removing - and then finding a new one of - was
the first motion shaft nut. It's a reverse thread and neither Moss nor
Abingdon Motors had one at the time (showed in their inventory but turned
out to be for the TD/TF transmission). Assume right off you're going to
have to replace it and order one before you take yours off - and try it for
fit before you trash your old one. As far as what to replace - naturally
you'll want to replace the first motion shaft bearing, the first motion
shaft oil seal, and the rear mainshaft bearing. The other parts to be
replaced will really depend on how worn they are. If you haven't already
done so in the past, you'll also want to replace your rear transmission
mounts (they should be made of rubber mush by now).

I can't help you with the rear axle ratio.

Good luck to you -

Gene Gillam

[Frank O_ The Mountain]

In a message dated 1/12/00 11:38:15 AM Pacific Standard Time,
CFritz7001@aol.com writes:

[Jorolibb@aol.com]

Carl,

You might as well figure on replacing all the bearings and seals. As said
before, look for a broken rear cover (aluminum) and worn selector rod bores
in the remote. The thrust bearing and shims might as well be replaced while
it is apart too. Do be careful when removing the nut on the input shaft, left
hand thread as noted in another reply. When reassembling the lay shaft and
needle bearings, have a dummy shaft made up, 3/4" if I remember right, that
is just as long as the assembly, including the thrust bearings on either end.
Lower this into the housing and then push it out with the new layshaft (these
are always worn out). It is pretty straight forward of a box to rebuild and
shouldn't be to much trouble.

Good wrenching,

John Libbert
TC 2138
J2 3118

[Roger Furneaux]

John Libbert wrote:
have a dummy shaft made up, 3/4" if I remember right, that

>is just as long as the assembly, including the thrust bearings on either end.
>Lower this into the housing and then push it out with the new layshaft (these
>are always worn out). It is pretty straight forward of a box to rebuild and
>shouldn't be to much trouble.

This dummy is only used for a few seconds, and can very well be made of
WOOD, either a thin broomstick or wooden dowel rod is easily obtainable.
Cheaper and easier than metal!

For a quieter g/box, keep the end-float of the layshaft cluster to no more
than 4 thou
of an inch. This might mean making thicker than std. thrust brgs. I believe
Phil Marino does these in the 'States, here in England Jerry Brown is your
man.

ocTagonally

Roger Furneaux