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MG TD TF 1500 - TD gearbox & diff oil (again)

There's a bunch of info in the archives, but it doesn't seem definitive so I thought I'd bring it up again. ;-)

The answers to the question "Which oil?" seems to fall into three categories:
1. "Use what the book says."
2. "Use hypoid, but not GL5/EP ('cause it eats bronze syncros)."
3. "Use RedLine."

I say it's not definitive because it seems contradictory.

The "book" ("MG midget Series TD, Series TF Workshop Manual) says (for temps above 10ºF):
•Energol EP SAE 90
•Hypoid Filtrate Gear 90
•Ambroleum EP 90
•Duckham's Hypoid 90
•Castrol Hypoy
•Esso Expee Compund 90
•Mobilube GX 90
•Shell Spirax 90 EP

Some of those (like the Energol) claim to be EP, so that violates (2). Others (at least modern Castrol Hypoy) are EP and/or GL5 now, but perhaps weren't in 1956 when the book was published. I've no way of knowing.

RedLine make a good product, but I don't have any and I already own some LE Almasol. I really REALLY like LE products.

The Almasol states: "ALMASOL Pure Mineral Gear Lubricant is a balanced formulation of natural high VI paraffinic base oils, rust and oxidation inhibitors, wear-reducing agents and other additives which provide the highest level of wear reduction possible without the use of a chemically active EP agent.
It also contains ALMASOL, LE’s exclusive wear-reducing additive.
Some manufacturers of transmissions and gearboxes specify a “pure” or “straight” mineral oil gear lubricant. This means that this type of gear lubricant should not contain chemically active EP additives. These terms do not mean that the lubricant may not contain various other highly desirable additives."

My reading on that is that it won't attack bronze, but I've got a call in to the LE tech line to confirm.


LE also make another oil called Monolec: "Monolec Gear Lubricants are versatile, mutli-viscosity, extreme pressure gear oils. They met the demanding fleet requirements of all types of differentials (including limited slip), transmissions and industrial enclosed gearboxes, that require multi-viscosity EP gear oils.
All of the features give the user many performance benefits; longer gear life with less maintenance expense, fewer hours of lost production, extended drain intervals with less make-up between drains, and the versatility of one product that can deliver exceptional performance in almost all types of gearboxes. " "Use in worm gearboxes and in any gearboxes that have bronze gears, thrust washers, or other parts that require an extreme pressure gear oil."

So we've got one LE product that claims to not have a chemically active EP agent (and they say to not use in applications requiring EP.)

That makes me question (2), since here's at least 1 EP product safe for bronze, plus "the book" specifies a couple of EP products.

So my question is this:
Is EP required, or optional?

Cheers!


Rob Edwards

Rob, when did you say that book was published? Personally, I'm using Redline MT90 in the gearbox.
Bud Krueger

3/56

The state of the lubricator's art has changed a bit since then....

As I said, I have enough LE here, right now, to do the job.....

Cheers!
Rob Edwards

Rob,

In 1860 the most intelligent white men in the western world (not just the Western Hemisphere) KNEW that the gorilla was a myth. By 1870 there was a gorilla in a cage in London.

The lubricant recommendations in the TD/TF Workshop Manual were current and (presumably) state of the art as of the early 1950s. Time marches on, and knowledge advances.

You like that LE stuff - go for it. It is, after all, your gearbox.

I also use Red Line MT-90 in my TD.

My own personal opinion, however, is that improper shifting (beating the synchros, no pause in neutral) can undo the very best intentions of any gearbox oil manufacturers' chemists and techies.

Cheers!

Cliff
C A Schnell

Redline mt90.... and Cliff is right... I double clutch up and double clutch down and add the slight pause...never a nick or crunch...(how do you race a td with stock gearbox?)
gblawson

i have read in a couple of old car publications that the chemical formulations of the EP's made in the last 15 years won't effect the brass. (hmmmm....now if i could only find the reference for you guys where i read that. darn....) regards, tom
tm peterson

upon further review, and research, it appears that a calendar date for EP oils that are compatible with brass is not accurate. there are EP oils that have been formulated to be compatible with brass and bronze, but not all as i had recalled. read the product specs to determine compatibility. i found a few EP oils that are compatible in just a few minutes search on the web. regards, tom
tm peterson

From looking at the product sheet for MT-90, RedLine specifies that it (MT-90) is suitable for applications requiring an EP lube.

Unfortunately, that doesn't answer my original question: Is EP oil required in TD gearboxes and/or diffs?

Anyone?

Cheers!
Rob Edwards


Rob,
I don't care to further the discussion regarding "new" oil specifications, etc., but the Factory Workshop manual section on lubrication clearly recommends EP type oils for hypoid gears in the section for the transmission and the rear axle on page P.2, sec B.

Dallas
D C Congleton

Thanks, Dallas.

I've done a bit more research and learned that hypoid gears require EP lubes. Since, as you point out, the heading for section B of the chart (which is where I got the list I posted above -- you'll notice it looks familiar.... ;-) does clearly say "Hypoid Gear". So for the diff at least I need EP. (And a correction -- I've found conflicting info on the RedLine website. I found one doc that says that MT-90 is suitable for applications requiring EP lubes. In other places it says that MT-90 is not EP; for that you need their 75W90 High Performance Gear Oil, which is GL-5/EP rated.)

I've spoken with Lubrication Engineers and they say that their 607 Almasol is EP and is not appropriate for bronze components, but that 607 is no longer available (it's now a different number --6615?) and they're selling 401 Almasol which IS safe for bronze components as it's non-EP. Problem now is that I don't know which I've got! I bought it bulk from a shop. I guess I need to go back and look at the drum.

But.....
Since The Book says EP for diff, gearbox and steering, does that mean that there are no bronze components in the gearbox about which to be worried? (Or does it mean that the factory figured the rest of the car would be used up before the sulfur in the gear oil attacking the syncros would be a concern? ;-)
Rob Edwards

I think it means the original objective is to have an extreme pressure oil because of the hypoid cut gears. It seems to me that this requirement stays the same- the problem is the awareness that some oil brands have additives or formulation that we don't need.

SO your research is well grounded - we now need a EP oil with out the sulphur or whatever that would damage bronze or brass components, which we do have.

I have been using Castrol Hypoy C Gear Oil 80W-90 in both my TD and my Healey. I'm not sure if it is still the old formulation or a new one.? It does not have a caution about bronze or brass but I guess in today's market place the consumer has to ask.


Here is a link-
http://www.castrol.com/castrol/productdetailmin.do?categoryId=82915493&contentId=6004016

Dallas
D C Congleton

Hmm. Since there are no hypoid gears in the trans, EP would not be required there. But because the manual makes no distinction between the trans and the diff (and EP oils of 1956 would most certainly have attacked bronze), I'm thinking the most likely explanation is that they just didn't consider the reduction of service life of the syncros to be a concern and by specifying the same gear oil everywhere it would make life simpler for all involved. I read somewhere that it was considered normal & acceptable to have to rebuild the engine after ca. 50,000 miles? If that's the case, so what if the trans only lasts about the same? ;-)

I couldn't find a caution about bronze on the Castrol website either, but the product data sheet does mention that Hypoy is 1.6% sulfur by weight....

I think bottom line is that I'll use different lubes for trans and diff.

Cheers, all!
Rob Edwards

60,000 was considered the pretty well the end... rebuild of engines (valves/bearings) might start at 20-25,000
My dad always told me to sell before 60,000, otherwise you were replacing everything...
The TD shop manual gives some startling service times...most we probably ignore!
In the 50's i remember having oil changed and the mechanic walking around the car with an oil can doing all the hinges, etc!
gblawson

There's actually a groove in the top of the MGB door hinges with a very small legend "oil" beside it. Wonder how many people actually do that...
Rob Edwards

GL-5; Specified for hypoid gear service but with shock loads and severe service operation. This grade has a high level of Extreme-Pressure additives that could be mildly corrosive to nonferrous parts. Most modern gear oils are non-reactive the sulfur is not just dissolved in oil but esterified and only reacts under pressure/heat of shearing and loads.

GL-4; Specified for hypoid gear service under severe service but without shock loading. Implies an EP/AW additive package that contains less EP additives than the GL-5 service classification.
Paul Wiley

This thread was discussed between 06/09/2007 and 08/09/2007

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.