115
PROP SHAFT, DRIVE SHAFTS AND DIFFERENTIAL
3. Do you know the tyres are good, some can create a bit
It is interesting to know that the 2000 automatic Mk II
of a whine? If necessary, swap them over from a car
Estate Triumphs have the same diff (according to
you know is not whining.
Leylands Parts Manual) as the Stag, as have the
4. The wheel bearings can emit a whine, but this is
'76-'77 manual overdrive 2000 estates.
normally speed sensitive from low speeds, within the
My Stag is fitted with a 2000 auto saloon diff of the
range of human hearing, so it `appears' to disappear
correct ratio, all I did was use the backplate off my
at higher speeds. Check whether you have excessive
Stag diff on the saloon diff. Not bad for £12.00 from
play and noise from the rear wheel bearings.
my local scrappy. However, be careful, as I
5. Are the joints on the main prop shaft from the
understand there were two different hypoid casings
gearbox and also the drive shafts out to the wheels
used on the saloons so the Stag backplate may not fit.
unworn and not partially seized?
Issue 119 (May 1990), page 28
6. The overdrive can emit a slight whine when engaged.
Differentials in Stags and 2000/2500
Is there any noise difference between overdrive
range. Mike Stevens wrote:
engaged or disengaged?
THERE HAVE BEEN a number of letters recently about
7. Are the diff output flanges loose or have play. If so, it
the differentials used in the Stag and the 2000/2500
is relatively easy to pop them out and replace the
range and their interchangability. This is my under-
bearings a press and bearing puller are very useful
standing of it.
for this.
The basic type of diff seems to be used in the Stag and
8. You have got oil in the diff, haven't you?
all 2000/2500 models and TR4a/5/6 (I think). The
If the above checks lead you to the conclusion that the
ratios used are:
diff is the problem, you now have to decide whether
All Stag 3.7:1
to either put up with the whine, or go for a new unit.
All 2000 Auto 3.7:1
Only you can judge whether or not you can put up
2000TC manual after about 1975 (Plastic grill
with it.
version) 3.7:1
One final word of warning is that not all diffs are quiet
2000 manual before 1975 (Mk I and metal grill Mk
when fitted. Reconditioning differentials is a highly
II) 4.11:1
skilled business and inevitably a very slight
All 2.5PI/2500TC/2500S 3.45:1
inaccuracy in meshing the gears results in a lot of
TR4a/5/6 3.45 (I think).
noise irrespective of whether the diff has new gears
likely to be available to us anyway!
fitted or not. I have come across a number of Stag
There are a number of ways of telling which diff you
owners who wish they had kept their `old' diffs, as it
have:
was quieter than the replacement.
1. Look at the number stamped on the flat part of the
A new diff needs a few hundred miles to settle down and
casing on the bottom. It should have two or three
run into the correct mesh, so don't reject your
letters and then up to five numbers. The letters
replacement on day one!
signify what it came from, and hence what the ratio
Issue 157 (October 1993), pages 17,18
should be.
LDxxxxx Normal Stag diff 3.7.
Differential Ratios. Stuart Yoon (10421)
MBxxxxx Mk I 2000,1 don't know about
asked how to check his differential ratio
manual/auto differences in Mk I
and was advised to remove the diff and
numbering probably 4.11.
count the gear teeth. Martin Nicholson
MExxxxx Mk II 2000 manual saloon probably
(3905) then wrote:
THERE IS A MUCH simpler, just as accurate method
4.11.
which is as follows:
MEAxxxxx Mk II 2000 manual estate probably
With the car in neutral, handbrake off and front wheels
4.11.
securely locked, jack up one of the rear wheels off the
MECxxxxx Mk II 2000 auto saloon probably 3.7.
ground. Put a chalk mark on the wheel and on the
MEDxxxxx Mk II 2000 auto estate probably 3.7.
prop shaft, then turn the wheel and count the
MGxxxxx All 2.5PI/2500TC/2500S saloon 3.45.
relationship between the number of wheel turns
MGAxxxxx 2.5PI/2500TC/2500S estate 3.45.
versus the number of prop shaft turns.
2. Look at the colour of the paint on the two output
If the correct Stag diff with a ratio of 3.7:1 is fitted, for
shaft flange nuts (only useful if the diff is off the car!)
every 10 full rotations of the wheel, the prop shaft will
3.45 diffs red.
rotate 18.5 times. What actually happens is that
3.7 diffs yellow.
because one output shaft of the diff is locked it `doubles
4.11 diffs white.
up' on the other output shaft. If this ratio isn't
The above two methods fall down after bits and pieces
achieved, I would guess that Stuart will have a 2000
have been swapped about, but it can give an indication.
3. The best/most accurate way is to count the turns of
manual saloon (70-75) 4.1:1 diff giving 20.5 prop
the prop shaft flange and the output flange, see the
shaft turns to 10 wheel turns or a 2500 saloon 3.45:1
letter by Martin Nicholson in issue 119, about this.
diff giving 17.25 prop shaft turns to 10 wheel turns.