AHExp

The 100 Forum

What oil do you run in your OD boxes!

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

NOHOME P P
O, Ontario, Canada   CAN
1967 MG MGB GT "Maggie (GT From Hell)"
Even the manuals seem to not agree on this one.

On MGBs, I have settled on straight non detergent 30 weight. Rational is that the detergent and the OD friction surfaces are non-simpatico.

I have also run Castrol 20-50 in the MGB gearboxes with no ill effects.

Is there a consensus?

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
ozhealey Avatar
ozhealey Tony P
Canberra, ACT, Australia   AUS
NOHOME,

I’m not sure you will get any consensus on this chestnut.

The AUSTIN HEALEY books specify engine oil (I believe non-detergent)
The TRIUMPH books specify gear oil (exactly the same O/D unit)

Noting the Gearbox and O/D share the same oil, the brass vs steel synchro rings play a part in choices.

For many years (20 to be exact) I used Penrite HPR40 (when I lived in the hot Australian climates) or HPR30 (when I lived in our colder regions) and I had absolutely no issues.

As components wore however, my O/D started to operate intermittently. I decided to flush out the oil and then use the synthetic oil REDLINE MT90. While this corrected the problem entirely (and the shifting is awesome in comparison) the unit did decide to leak noting the synthetic oils have a habit of challenging sealing the old components.

Earlier this year I did a full tear down and rebuild of both my gearbox and overdrive. I rebuilt the system using permatex “maximum synthetic” sealant on every joint and then filled up with REDLINE MT90. The unit operates beautifully and so far after 6 months I do not have a single drop of oil leaking from either the O/D or gearbox. Indeed I keep checking the level to make sure I have oil in there noting it is the first time in 22 years of owning my Healey I have not have a bit of weeping from the G’box and/or O/D.

Just my thoughts and opinion and there will be many others I’m sure.
Cheers
Tony

Britcarsource Bobby R
Knoxville, TN, USA   USA
I have ueed 20w50 motor oil in several big Healeys for 55 years with no problems.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
San Jose, California, USA   USA
+1 on MT-90. I've run it in my BJ8 for years and I think it provides a little quicker OD engagement, smoother shifts and less visible wear metal (these are subjective, of course). It is a big harder to restrain if you haven't sealed all joints recently and properly. I just put it in my BN2.

Raindog Avatar
Raindog Alan W
Saint Augustine, Florida, USA   USA
Redline MT-90 turned my NON-leaking 100-6 into a sieve. Went back to non-detergent 30W but thinking of using 40W non-detergent because of the high temps here in Florida. After the tranny heats up the shifting gets more difficult.
Alan

San Jose, California, USA   USA
In reply to # 195439 by Raindog Redline MT-90 turned my NON-leaking 100-6 into a sieve. Went back to non-detergent 30W but thinking of using 40W non-detergent because of the high temps here in Florida. After the tranny heats up the shifting gets more difficult.
Alan

How were the shifts with hot MT-90?

Raindog Avatar
Raindog Alan W
Saint Augustine, Florida, USA   USA
I honestly don't remember. I was obsessed with the leaks and it was during the Florida winter months with much cooler weather.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
ozhealey Avatar
ozhealey Tony P
Canberra, ACT, Australia   AUS
Bob,

As I said, I’ve been running MT-90 in my gearbox for around four years now and the performance of the O/D and the shifting is superb and a bit slicker than the mineral oil. Once I pulled the box apart and used the permatex maximum synthetic sealant I also have no leaks at all.

I have used both 30 and 40 wt mineral oil (non-detergent) Penrite HPR30 and HPR40 and while they were also good, I am absolutely sold on the MT-90 and while it is expensive I will be sticking with the MT-90.

Cheers
Tony

PAN Avatar
PAN Alwyn Keepence
Ipswich, Queensland, Australia   AUS
G'day again "NOHOME",
I try to avoid multi-grade oils in my gearbox/overdrive. I have used Penrite Gearbox Oil 40 for many years with excellent results.
Cheers,
Alwyn

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
NOHOME P P
O, Ontario, Canada   CAN
1967 MG MGB GT "Maggie (GT From Hell)"
Went with a straight 30 weight non-detergent. Same as I have used in the MGB boxes.

Significant part of the decision is that I can actually source the stuff here in Canada without having to resort to mail-order and border hassles. $50 in USA= $100 by the time it reaches my door.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions

Members Sign In   or   Create an Account

Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster





Join The Club

Sign in to ask questions, share photos, and access all website features

Your Cars

1954 Austin Healey 100

Text Size

Larger Smaller
Reset Save

Sponsor Links