<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=us-ascii" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 11.00.10570.1001"></HEAD>
<BODY>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial>Mike,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial>I am new to the Healey world but I am an engineer with an
automotive background who recently had a BN4 transmission with an overdrive
completely rebuilt. I could not find a consistent answer on the recommended oil
for the transmission. The original Healey manuals are not consistent either, the
shop manual recommends 20W50 and the Healey service bulletins from the day
recommend 30W. Coming up with the right oil is further complicated by the design
of a Healey transmission which is two different transmissions with a common oil
system. One transmission is a traditional gear type with syncro rings that are
not compatible with the additives in modern gear lubricants and the other is a
hydraulic pump. I am sure there will be much disagreement but these are the
steps I went through to select the oil I would use:</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial>1. The additives had to be compatible with brass and other
soft metals used in older transmissions.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial>2. The oil should be designed to work with gears and have some
level of EP protection. Note very few engine oils meet gear oil
specifications.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial>3. The oil should have a viscosity similar 30W engine oil
which was recommended in an Austin Service bulletin in 1960 replacing
20W50.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial>The oil that best fits all of these requirements is a 70W-90
GL4 gear oil. Red Line MT-90 meets this specification as does Pennzoil Synthetic
70W-90 GL4. I picked the Pennzoil as it costs less than the Red Line but both
should work well. Do not use a GL5 as the additives are not compatible with
brass. I looked into why Austin switched their recommended oil from 20W50 to 30W
and concluded it was for a lower viscosity at lower temperatures i.e. when the
transmission is cold. Viscosity is another important consideration. 70W-90 GL4
has the same viscosity as 30W engine oil above 35 degrees C and a better low
temperature viscosity. The only downside I have seen with Pennzoil Synthetic
70W-90 GL4 is that it can get through even the smallest openings and cracks and
the transmission may leak a little more but that is evidence the oil is getting
every where it should. I have heard Red Line MT-90 doesn't leak as much as the
Pennzoil.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial>For those that may doubt the viscosity claims please note that
engine oils and gears oils are classified differently and should be compared by
looking at the numbers on the can. See the attached viscosity
curve.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial>I trust this helps but I want to emphasize this is the
oil I use and I recommend you reach your own conclusion.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial>Harold</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=343023002-09082017><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV><BR>
<DIV lang=en-us class=OutlookMessageHeader dir=ltr align=left>
<HR tabIndex=-1>
<FONT size=2 face=Tahoma><B>From:</B> Healeys
[mailto:healeys-bounces@autox.team.net] <B>On Behalf Of </B>Michael
MacLean<BR><B>Sent:</B> Tuesday, August 08, 2017 5:47 PM<BR><B>To:</B> Healey
List<BR><B>Subject:</B> [Healeys] Russ Thompson<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV
style="FONT-SIZE: 16px; FONT-FAMILY: times new roman, new york, times, serif; COLOR: #000; BACKGROUND-COLOR: #fff">
<DIV id=yui_3_16_0_ym19_1_1502237499620_134651 dir=ltr>
Through a reference from the list I am having Russ Thompson in Northridge,
California rebuild my BN2 transmission. It is a low mileage (10,000 mi.
approx) transmission, but I wanted to be able to put it in and not have to take
it back out again. Good thing I took this precaution. Russ found the
overdrive stuck and would never have worked. Today he showed me the
accumulator piston. The smaller center piston was scored from dirt or crap
in the oil. Russ replaced it with a one piece piston from a Triumph
overdrive. There was a huge spring below it. Anyone heard of
this? He said engagement will be real positive now. Even with the
low mileage, the number 2 synchro was toast and will be replaced. The
other two were fine and will be re-used. All the gears showed very little
sign of wear. The reverse gear had some surface rust on the teeth, but
that can be blasted and it will be fine. Getting closer to having the
drive train is the car.</DIV>
<DIV id=yui_3_16_0_ym19_1_1502237499620_134884 dir=ltr>
I know I am going to start a discussion, but Russ recommends using 40wt motor
oil for the transmission. Anyone know what weight Redline MTL
is?<BR></DIV>
<DIV id=yui_3_16_0_ym19_1_1502237499620_134867 dir=ltr>Mike
MacLean<BR></DIV></DIV></BODY></HTML>