[TR] Rear axle oil - overall lubricants and new designs

[bill beecher]

Stay with a GL4 85/90w lube, I think j found it at NAPA. 
Bill
TS30766L

“The harder I work, the luckier I get”  H. Ford

On May 9, 2026, at 2:45 AM, Mark Bradakis <mark at bradakis.com> wrote:

For some reason this was flagged by Mailman.  No idea why.

mjb.

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-----Original Message-----

From: Triumphs <triumphs-bounces at autox.team.net> On Behalf Of John Macartney
Sent: Thursday, May 7, 2026 3:30 PM
Cc: triumphs at autox.team.net
Subject: [TR] Rear axle oil

Had an early night after spending the day sorting old Standard-Triumph handbooks (among lots of other stuff) and have just checked the grade for Standard Vanguard and TR3/3A as both used the same axle. Factory recommended an 85W90 GL4 type Hypoy as offered by Shell, BP, Castrol, Duckhams, Texaco. IOW, a hyper lube type with an ultra high resistance to shear. Does the stuff you have offer the same lubricity properties? Never heard of it myself but most modern oils are a complete mystery to me anyway. Still can’t get used to the family daily driver only being allowed a 0w20 full synthetic. Pours like water!

Jonmac

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Regarding the 0w20, I'd like to have a bit of a rant on today's mechanical designs.

When we take a look at the longevity of the supposed "high technology" direct injection engines of today and over the past say 10-15 years, it is woefully clear that these driveline designs are not lasting.  Sure, they provide performance and a lot of mpg per BHP per cc/cid, but all that tech designs have all sorts of problems.
Might that be from too thin oil?  As a long time cross-discipline control system professional,  the lubricants  or use of improper spec lubricants may be a cause, but not entirely, as when you tear into these new tech engines, they are yes, mechanical marvels controlled by complex computer management, but also, mechanical nightmares more likely to self-destruct if a microparticle of contaminate invades the wrong internal spot, a sensor allows the wrong stuff to enter the engine somewhere or the coolant level drops because some plastic coolant manifold or connection has a weak spot and suddenly dumped all the coolant creating a high temp spike on the close tolerance components.

We love the new tech performance, but at what cost?

People slammed the Triumph Stag 2997 CC OHC V8 for its design "flaws" but when I dive into some of these newer engines there are strikingly similar designs copied, I have seen across many other engine manufacturers including GM, Mercedes, Toyota, Ford, JLR and others.  One example is timing chains, OHC design, etc.  Today's OHC engines, all of them, have issues with timing chain tensioners, guides, oil pumps which are manifested from engine designs over 75 years ago but cost cut even more and designed to very narrow performance limits and very close tolerance requirements.

When I look at these newer high-performance engines, they all appear to have the same old issues: multiple simplex roller timing chains (some use internal rubber belts!!!)  held in place by insufficiently designed guides and tensioners driving all sorts of internal components like oil/fuel/water pumps buried deep internally into the engine, variable valve timing, variable stroke, very high-pressure requirements for oil and fuel with electronics like solenoids and sensors operating in the component lubricants, and they all have significant design structural problems from material and cost scrimping and lack of real longevity whether they are petrol/gas or diesel.

I have been looking at the various JLR newer models, and what incredible value can be had in say a Range Rover autobiography /SV/Dynamic/ that had cost 180k USD or far more, yet with a blown 5.0 liter engine, they are relatively worthless.  To rebuild one of those 3.0 or 5.0 engines, have a look at some of the teardown and rebuilds of any modern direct injection engine and you will quickly see the engines are all completely disposable designs; materials are skimped in the blocks to save manufacturing time, weight and maximize cooling, but when they break, they self-destruct. Labor alone to tear down and reassemble is often more that the OEM cost of the entire engine, and the factory does not provide rebuild kits.  What is a pound of engine webbing structural aluminum removed from a 600 bhp supercharged engine as an assembly or weight saving design on a 6000# weight vehicle?  Maybe if designed for the track that amounts to a fraction of a second of speed, but a road vehicle?!?

Lubricants:
Historically, the fact was, API / SAE lubricants designed for components were once supposed to increase the range of mechanical protections with new specifications as time went on, where today, a mechanical component may be designed only for one very narrow type of lubricant that was designed only for that unique application.

The API/ SAE "meets or exceeds" statements must be carefully dissected to understand exactly what the lubricant use range and components lubricants are approved, which may take significant research.

If you decide to use your "favorite brand" oil or coolant in a modern driveline component not certified for use in that narrow design, you might be unknowingly starting the self-destruction timer.

So, to answer the question for our old and very reliable vehicles, BEGIN with the Owner's Manual / Factory Manual specification for your lubricants in and on your components as they were designed by the manufacturer, and if that type of lubricant is not available, look and understand what and why it was replaced with a later API/SAE tested lubricant that "should" add increased protection in that application.
AVOID AT ALL COSTS, "my buddies or I uses this and swears by it..."  I typically do not trust my local parts shoppe counter person for lubricant recommendation unless that counter person was once a master mechanic or factory trained tech, that being rare.  There are reams of Technical Service Bulletins where the factory engineers got it wrong too, only discovered during or after warranty periods.
Lubrication is its own science, but if you read the specs, you will get the limitations and also the mechanics tales for snake oil.

Caveat Emptor ya'll.

Glenn a.k.a. StagByTriumph


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