--===============0494778417783509606==
boundary="Apple-Mail=_4A848DDD-8979-4C6E-BD9C-1FE65FCA2B8F"
--Apple-Mail=_4A848DDD-8979-4C6E-BD9C-1FE65FCA2B8F
Content-Transfer-Encoding: quoted-printable
charset=utf-8
There are flame wars on this subject on the MGB Experience forum=E2=80=A6
But here=E2=80=99s my logic:
The factory manuals specify =E2=80=9Cengine oil=E2=80=9D for both =
overdrive and non-overdrive transmissions.
If you analyze that recommendation, you would conclude that the key =
characteristic they are concerned about is viscosity. Analysis follows:
Transmission oil does not have to deal with combustion blow-by or high =
heat, so it doesn=E2=80=99t need detergents or protection from thermal =
breakdown. And my personal take on it (though this is apparently highly =
controversial) is that for transmission oil it is better to use a =
single-grade oil, as multi-grade oils break down into the single-grade =
stock over time, and one does not change the transmission oil very often =
compared to engine oil (or ever, IME). It=E2=80=99s not that multi-grade =
would hurt; it is that its benefits, if any, won=E2=80=99t last, and the =
single-grade base stock is equivalent to the lightest grade in the =
rating; i.e. 20W50 breaks down into 20W.
But some people will fly off the handle at the suggestion that 20W50 is =
not ideal. Their logic goes something like this: =E2=80=9Cthe manual =
says =E2=80=98engine oil=E2=80=99 for the transmission; for my climate =
it recommends 20W50 engine oil for the engine, therefore 20W50 is the =
only correct oil for the transmission.=E2=80=9D I believe it is only the =
later model MGs that have this particular recommendation (20W50) in the =
drivers handbook.
Anyway, backing up a paragraph or two, to my mind there is a significant =
difference between the standard transmission, which uses oil for splash =
lubrication only, and the OD transmission, which uses oil as hydraulic =
fluid with a planetary gearset, much like an automatic transmission. =
Automatic transmissions are extremely sensitive to viscosity =E2=80=94 I =
don't think you would have much luck with 90W gear oil in an auto trans.
So that is my thinking behind my suggestion. Are you sure the article =
you read was specifically about OD?
--
Max Heim
'66 MGB
> On Jan 18, 2019, at 8:22 AM, Jack Wheeler <jwheeler1947@yahoo.com> =
wrote:
>=20
> Hi Max. No, I'm not sure, but it is something I am looking in to. I =
have used straight 50 Wt. motor oil for years, and it has always worked =
fine. Based on the article I saw recently in the Tech Issue of "MG =
Driver" magazine (starting on page 46) I switched to EP 85/90 GL-4 gear =
oil. I couldn't find straight 90 Wt., so I used the closest GL-4 oil I =
could find, which was 85/90. So do you think this change could be =
causing my overdrive not to engage. If so, then someone ought to advise =
"MG Driver" magazine about the error in their article. Thanks.
>=20
> Jack
>=20
> On Thursday, January 17, 2019, 11:58:16 PM EST, Max Heim via Mgs =
<mgs@autox.team.net> wrote:
>=20
>=20
> Are you sure it isn't the gear oil?
>=20
> The factory has always called for engine oil. There has been a lot of =
ridiculous debate over precisely what grade of engine oil (personally, I =
don=E2=80=99t think it matters, but let=E2=80=99s not start that), but =
there is certainly a large difference in viscosity between say 20W50, =
and 85W90. The overdrive, unlike the rest of the transmission, uses oil =
in a hydraulic function, not just as splash lubrication, so viscosity is =
probably very important.
>=20
> --
> Max Heim
>=20
>=20
>=20
>> On Jan 17, 2019, at 11:13 AM, Jack Wheeler via Mgs =
>>=20
>> Does anyone have a good exploded diagram of the overdrive unit used =
in a 1971 MGB, that you could send to me? I am particularly interested =
in the pump assembly. I changed the oil in my gearbox this week, using =
EP 85/90 GL-4 gear oil, as recommended in a recent article in the MG =
Driver magazine.
>>=20
>> While the car was up in the air, I noticed a leak around the plug =
which holds the pump assembly in place. So, I removed the pump, careful =
to keep all the pieces in the order in which they came out. I cleaned =
everything up, and reinstalled the pump assembly and plug (part number =
466-315 in the Moss catalog), with a new gasket. I thought I had all of =
the pieces of the pump assembly (items 62-66 in the Moss diagram) in the =
right order when I reinstalled it, but when I took the car out for a =
test drive, the overdrive would not engage.
>>=20
>> In addition to trying to keep the pieces in the order in which they =
came out, I also used the exploded diagram in the Moss catalog (Page 41) =
as a guide. The Moss diagram, however, is different than my overdrive =
unit. Moss says their diagram is for cars from 1968 to 1980, but =
apparently, some things were changed during that time frame. I can't =
believe the engineers would let anything go unchanged for 12 years! It =
looks like the plunger (Moss part number 466-305) shown in the Moss =
catalog diagram has a roller on the end of it. My plunger does not have =
a roller on the end of it. Maybe this will give you a lead to which =
diagram I am looking for.
>>=20
>> So, that leaves me looking for a good exploded diagram of the unit =
used in a 1971 model. Can anyone help with that, or does anyone have =
any suggestions as to what I might have done to make the overdrive not =
work, when it has always worked fine. Thanks.
>>=20
>> Jack Wheeler
>> _______________________________________________
>>=20
>> Donate: http://www.team.net/donate.html
>> Suggested annual donation $12.75
>>=20
>> Archive: http://www.team.net/pipermail/mgs
>>=20
>> Unsubscribe: =
http://autox.team.net/mailman/options/mgs/mvheim@sonic.net
>=20
> _______________________________________________
>=20
> Donate: http://www.team.net/donate.html =
<http://www.team.net/donate.html>
> Suggested annual donation $12.75
>=20
> Archive: http://www.team.net/pipermail/mgs =
<http://www.team.net/pipermail/mgs>
>=20
> Unsubscribe: =
http://autox.team.net/mailman/options/mgs/jwheeler1947@yahoo.com =
<http://autox.team.net/mailman/options/mgs/jwheeler1947@yahoo.com>
--Apple-Mail=_4A848DDD-8979-4C6E-BD9C-1FE65FCA2B8F
Content-Transfer-Encoding: quoted-printable
charset=utf-8
<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D"">There are flame wars on this subject on the MGB Experience =
forum=E2=80=A6<div class=3D""><br class=3D""></div><div class=3D"">But =
here=E2=80=99s my logic:</div><div class=3D""><br class=3D""></div><div =
class=3D"">The factory manuals specify =E2=80=9Cengine oil=E2=80=9D for =
both overdrive and non-overdrive transmissions.</div><div class=3D""><br =
class=3D""></div><div class=3D"">If you analyze that recommendation, you =
would conclude that the key characteristic they are concerned about is =
viscosity. Analysis follows:</div><div class=3D""><br =
class=3D""></div><div class=3D"">Transmission oil does not have to deal =
with combustion blow-by or high heat, so it doesn=E2=80=99t need =
detergents or protection from thermal breakdown. And my personal take on =
it (though this is apparently highly controversial) is that for =
transmission oil it is better to use a single-grade oil, as multi-grade =
oils break down into the single-grade stock over time, and one does not =
change the transmission oil very often compared to engine oil (or ever, =
IME). It=E2=80=99s not that multi-grade would hurt; it is that its =
benefits, if any, won=E2=80=99t last, and the single-grade base stock is =
equivalent to the lightest grade in the rating; i.e. 20W50 breaks down =
into 20W.</div><div class=3D""><br class=3D""></div><div class=3D"">But =
some people will fly off the handle at the suggestion that 20W50 is not =
ideal. Their logic goes something like this: =E2=80=9Cthe manual says =
=E2=80=98engine oil=E2=80=99 for the transmission; for my climate it =
recommends 20W50 engine oil for the engine, therefore 20W50 is the only =
correct oil for the transmission.=E2=80=9D I believe it is only the =
later model MGs that have this particular recommendation (20W50) in the =
drivers handbook.</div><div class=3D""><br class=3D""></div><div =
class=3D"">Anyway, backing up a paragraph or two, to my mind there is a =
significant difference between the standard transmission, which uses oil =
for splash lubrication only, and the OD transmission, which uses oil as =
hydraulic fluid with a planetary gearset, much like an automatic =
transmission. Automatic transmissions are extremely sensitive to =
viscosity =E2=80=94 I don't think you would have much luck with 90W gear =
oil in an auto trans.</div><div class=3D""><br class=3D""></div><div =
class=3D"">So that is my thinking behind my suggestion. Are you sure the =
article you read was specifically about OD?</div><div class=3D""><br =
class=3D""></div><div class=3D""><br class=3D""></div><div class=3D""><div=
class=3D"">
<div style=3D"color: rgb(0, 0, 0); letter-spacing: normal; text-align: =
start; text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;" class=3D""><div style=3D"color: rgb(0, 0, 0); =
letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D""><div style=3D"margin: 0px; font-size: 13px;" =
class=3D"">--</div><div style=3D"margin: 0px; font-size: 13px; =
min-height: 16px;" class=3D"">Max Heim</div><div style=3D"margin: 0px; =
font-size: 13px;" class=3D"">'66 MGB</div></div></div>
</div>
<br class=3D""><div><blockquote type=3D"cite" class=3D""><div =
class=3D"">On Jan 18, 2019, at 8:22 AM, Jack Wheeler <<a =
href=3D"mailto:jwheeler1947@yahoo.com"; =
class=3D"">jwheeler1947@yahoo.com</a>> wrote:</div><br =
class=3D"Apple-interchange-newline"><div class=3D""><div class=3D""><div =
class=3D"ydp4d891059yahoo-style-wrap" style=3D"font-family:Helvetica =
Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div class=3D""></div>=
<div class=3D"">Hi Max. No, I'm not sure, but it is =
something I am looking in to. I have used straight 50 Wt. motor =
oil for years, and it has always worked fine. Based on the article =
I saw recently in the Tech Issue of "MG Driver" magazine (starting on =
page 46) I switched to EP 85/90 GL-4 gear oil. I couldn't find =
straight 90 Wt., so I used the closest GL-4 oil I could find, which was =
85/90. So do you think this change could be causing my overdrive =
not to engage. If so, then someone ought to advise "MG Driver" =
magazine about the error in their article. Thanks.</div><div =
class=3D""><br class=3D""></div><div class=3D"">Jack<br =
class=3D""></div><div class=3D""><br class=3D""></div>
=20
</div><div id=3D"ydp386e44f7yahoo_quoted_8653398412" =
class=3D"ydp386e44f7yahoo_quoted">
<div style=3D"font-family:'Helvetica Neue', Helvetica, =
Arial, sans-serif;font-size:13px;color:#26282a;" class=3D"">
=20
<div class=3D"">
On Thursday, January 17, 2019, 11:58:16 PM EST, Max =
Heim via Mgs <<a href=3D"mailto:mgs@autox.team.net"; =
class=3D"">mgs@autox.team.net</a>> wrote:
</div>
<div class=3D""><br class=3D""></div>
<div class=3D""><br class=3D""></div>
<div class=3D""><div id=3D"ydp386e44f7yiv2377926932" =
class=3D""><div class=3D""><div class=3D"ydp386e44f7yiv2377926932">Are =
you sure it isn't the gear oil?</div><div =
class=3D"ydp386e44f7yiv2377926932"><br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"></div><div class=3D"ydp386e44f7yiv2377926932">The factory =
has always called for engine oil. There has been a lot of ridiculous =
debate over precisely what grade of engine oil (personally, I don=E2=80=99=
t think it matters, but let=E2=80=99s not start that), but there is =
certainly a large difference in viscosity between say 20W50, and 85W90. =
The overdrive, unlike the rest of the transmission, uses oil in a =
hydraulic function, not just as splash lubrication, so viscosity is =
probably very important.</div><div class=3D"ydp386e44f7yiv2377926932"><br =
class=3D"ydp386e44f7yiv2377926932" clear=3D"none"></div><div =
class=3D"ydp386e44f7yiv2377926932">
<div class=3D"ydp386e44f7yiv2377926932">--</div><div =
class=3D"ydp386e44f7yiv2377926932">Max Heim</div><div =
class=3D"ydp386e44f7yiv2377926932"><a shape=3D"rect" =
class=3D"ydp386e44f7yiv2377926932" href=3D"mailto:mvheim@sonic.net"; =
rel=3D"nofollow" target=3D"_blank">mvheim@sonic.net</a></div><div =
class=3D"ydp386e44f7yiv2377926932"><br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"></div><br =
class=3D"ydp386e44f7yiv2377926932Apple-interchange-newline" =
clear=3D"none">
</div>
<br class=3D"ydp386e44f7yiv2377926932" clear=3D"none"><div =
class=3D""><blockquote class=3D"ydp386e44f7yiv2377926932" =
type=3D"cite"><div class=3D"ydp386e44f7yiv2377926932yqt1232777940" =
id=3D"ydp386e44f7yiv2377926932yqt52795"><div =
class=3D"ydp386e44f7yiv2377926932">On Jan 17, 2019, at 11:13 AM, Jack =
Wheeler via Mgs <<a shape=3D"rect" class=3D"ydp386e44f7yiv2377926932" =
href=3D"mailto:mgs@autox.team.net"; rel=3D"nofollow" =
target=3D"_blank">mgs@autox.team.net</a>> wrote:</div><br =
class=3D"ydp386e44f7yiv2377926932Apple-interchange-newline" =
clear=3D"none"><div class=3D"ydp386e44f7yiv2377926932"><div =
class=3D"ydp386e44f7yiv2377926932"><div =
class=3D"ydp386e44f7yiv2377926932ydp626bf091yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, =
sans-serif;font-size:13px;">Does anyone have a good exploded diagram of =
the overdrive unit used in a 1971 MGB, that you could send to me? =
I am particularly interested in the pump assembly. I changed the =
oil in my gearbox this week, using EP 85/90 GL-4 gear oil, as =
recommended in a recent article in the MG Driver magazine.</div><div =
class=3D"ydp386e44f7yiv2377926932ydp626bf091yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, =
sans-serif;font-size:13px;"><br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"></div><div =
class=3D"ydp386e44f7yiv2377926932ydp626bf091yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, =
sans-serif;font-size:13px;">While the car was up in the air, I noticed a =
leak around the plug which holds the pump assembly in place. So, I =
removed the pump, careful to keep all the pieces in the order in which =
they came out. I cleaned everything up, and reinstalled the pump =
assembly and plug (part number 466-315 in the Moss catalog), with a new =
gasket. I thought I had all of the pieces of the pump assembly =
(items 62-66 in the Moss diagram) in the right order when I reinstalled =
it, but when I took the car out for a test drive, the overdrive would =
not engage.</div><div =
class=3D"ydp386e44f7yiv2377926932ydp626bf091yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, =
sans-serif;font-size:13px;"><br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"></div><div =
class=3D"ydp386e44f7yiv2377926932ydp626bf091yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, =
sans-serif;font-size:13px;">In addition to trying to keep the pieces in =
the order in which they came out, I also used the exploded diagram in =
the Moss catalog (Page 41) as a guide. The Moss diagram, however, =
is different than my overdrive unit. Moss says their diagram is =
for cars from 1968 to 1980, but apparently, some things were changed =
during that time frame. I can't believe the engineers would let =
anything go unchanged for 12 years! It looks like the plunger =
(Moss part number 466-305) shown in the Moss catalog diagram has a =
roller on the end of it. My plunger does not have a roller on the =
end of it. Maybe this will give you a lead to which diagram I am =
looking for.<br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"></div><div =
class=3D"ydp386e44f7yiv2377926932ydp626bf091yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, =
sans-serif;font-size:13px;"><br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"></div><div =
class=3D"ydp386e44f7yiv2377926932ydp626bf091yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, =
sans-serif;font-size:13px;">So, that leaves me looking for a good =
exploded diagram of the unit used in a 1971 model. Can anyone help =
with that, or does anyone have any suggestions as to what I might have =
done to make the overdrive not work, when it has always worked =
fine. Thanks.</div><div =
class=3D"ydp386e44f7yiv2377926932ydp626bf091yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, =
sans-serif;font-size:13px;"><br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"></div><div =
class=3D"ydp386e44f7yiv2377926932ydp626bf091yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, =
sans-serif;font-size:13px;">Jack Wheeler<br =
class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"></div></div>_______________________________________________=
<br class=3D"ydp386e44f7yiv2377926932" clear=3D"none"><br =
class=3D"ydp386e44f7yiv2377926932" clear=3D"none"><a shape=3D"rect" =
class=3D"ydp386e44f7yiv2377926932" href=3D"mailto:Mgs@autox.team.net"; =
rel=3D"nofollow" target=3D"_blank">Mgs@autox.team.net</a><br =
class=3D"ydp386e44f7yiv2377926932" clear=3D"none">Donate: <a =
href=3D"http://www.team.net/donate.html"; =
class=3D"">http://www.team.net/donate.html</a><br =
class=3D"ydp386e44f7yiv2377926932" clear=3D"none">Suggested annual =
donation $12.75<br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"><br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none">Archive: <a href=3D"http://www.team.net/pipermail/mgs"; =
class=3D"">http://www.team.net/pipermail/mgs</a><br =
class=3D"ydp386e44f7yiv2377926932" clear=3D"none"><br =
class=3D"ydp386e44f7yiv2377926932" clear=3D"none">Unsubscribe: <a =
href=3D"http://autox.team.net/mailman/options/mgs/mvheim@sonic.net"; =
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br class=3D"ydp386e44f7yiv2377926932" =
clear=3D"none"></div></div></blockquote></div><br =
class=3D"ydp386e44f7yiv2377926932" clear=3D"none"></div></div><div =
class=3D"ydp386e44f7yqt1232777940" =
id=3D"ydp386e44f7yqt17217">_______________________________________________=
<br clear=3D"none" class=3D""><br clear=3D"none" class=3D""><a =
shape=3D"rect" href=3D"mailto:Mgs@autox.team.net"; rel=3D"nofollow" =
target=3D"_blank" class=3D"">Mgs@autox.team.net</a><br clear=3D"none" =
class=3D"">Donate: <a shape=3D"rect" =
href=3D"http://www.team.net/donate.html"; rel=3D"nofollow" =
target=3D"_blank" class=3D"">http://www.team.net/donate.html</a><br =
clear=3D"none" class=3D"">Suggested annual donation $12.75<br =
clear=3D"none" class=3D""><br clear=3D"none" class=3D"">Archive: <a =
shape=3D"rect" href=3D"http://www.team.net/pipermail/mgs"; rel=3D"nofollow"=
target=3D"_blank" class=3D"">http://www.team.net/pipermail/mgs</a><br =
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class=3D"">http://autox.team.net/mailman/options/mgs/jwheeler1947@yahoo.co=
m</a><br clear=3D"none" class=3D""></div></div>
</div>
</div></div></div></blockquote></div><br =
class=3D""></div></body></html>=
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