Apologies for re-visiting this EP90 GL4 and GL5 + 20/50 Gear

[s-type]

Apologies for re-visiting this EP90 GL4 and GL5 + 20/50

Does anyone actually know the correct answer? I'm not sure there is a single correct answer?

So, according to the Jaguar manual it says early non syncro gearboxes, should have 20/50 (or in those days 30SAE).
It then says at the end of the chapter later cars with syncro should have EP 90. (or 80/90 these days)

Ok simple? Err no. So EP90 (or EP 80/90 as it now is ) is available in GL4 and GL5, this just means the amount of additives in it (lets not confuse the semi synthetic qualities with the GL raiting).
However use EP90 GL5 in a car with brass bearings and you will have trouble. GL4 is (according to Halfords printed in store guide) gearbox oil and GL5 rear diff oil. I can also see the landrover / Trumpy guys need GL4 not GL5. However im not sure what a Jagaur needs and if it has the bearing affected in the box by GL5... But I now think GL4 is correct for Jaguar not GL5...

Now lets add the curve ball in. When I had my syncro gearbox and laycock overdrive rebuilt (very big and reputable company) the guy said use 20/50 not EP 90 or it will burn the overdrive clutch cone. I have been googling this and many many people are sayign the same thing that laycock overdrive's don't like EP90.

So I go to Pentire Oil's home page... For a MK2 (Mine is a S-type) they recommend their Gear oil 30, NOT EP 90... (for all years including overdrive). Infact they say that you should not use EP90 in a laycock overdrive, and this is from Pentite...
http://www.angloparts.com/images_ap/new ... ochure.pdf

So go to Millers and they say EP90!!!!! (and apparently its good for overdrives!)
http://www.millersoils.net/1_Millers_frame_CLASSIC.htm



So depending where you look each answer is correct. Even GL5...

EP90 GL4

EP90 GL5

20/50 / SAE30

Roll the dice and stick it in....

I was going to use EP90 GL5, but I now believe that is totally wrong. I then thought EP80/90 GL4, but I am now thinking 20/50!!!!!!!!

The answer “just do what it says in the Jaguar manual” I believe is incorrect because they may not have known that EP90 burned the overdrive cones with the shared oil from the gearbox. (they were never built by Jaguar) Also early boxes used 20/50 so why cant that be used on a later box, because we know syncros are not damaged with out EP90...

NIGHTMARE.

Anyone have any cold hard facts?

[scimagain]

This may (or maybe not) a help to you.
I ran a Scimitar 6a with overdrive for about 100k miles. The oil used in the gearbox was EP80 as suggested by the owners manual.
No problems in any form. When I parted with the car it had done over 150k on the drive train and it was still in good condition.

My current 6a has EP80/90 in the box, simply because that was what the garage had in stock and their statement was that it was the normal practice to fill up with this grade rather than using 80 for the gearbox and 90 for the diff. It doesn't appear to have caused any problems so far, I've only done about 2k since I got the car (about three years ago).

Hope that is of use to you.

[s-type]

This may (or maybe not) a help to you.
I ran a Scimitar 6a with overdrive for about 100k miles. The oil used in the gearbox was EP80 as suggested by the owners manual.
No problems in any form. When I parted with the car it had done over 150k on the drive train and it was still in good condition.

My current 6a has EP80/90 in the box, simply because that was what the garage had in stock and their statement was that it was the normal practice to fill up with this grade rather than using 80 for the gearbox and 90 for the diff. It doesn't appear to have caused any problems so far, I've only done about 2k since I got the car (about three years ago).

Hope that is of use to you.

thanks, Do you know if it was EP80 GL4 or GL5 and the same question for the 6a and the EP80/90? Did either have an overdrive I assume both were/are syncro's?

Its funny people are saying they are getting 100K out of 20/50 and 100K out of EP's!!!

I think there is no correct answer!

[suffolkpete]

My Matra is supposed to use EP80 GL4 in the transaxle. I've been using Castrol Syntrax Driveline 75/90 which is a synthetic oil which claims to meet both GL4 and GL5 specs. I've done over 12,000 km and nothoing's broken yet.

[scimagain]

The only info I can supply re the EP80 oil is that it was Duckhams
The handbook was published back in the 70's and does not list GL numbers.
Yes, both cars were / are manual with overdrive and are syncro boxes. I should also state that the oil was changed at service intervals - just in case someone thinks that I ran the car on the original oil for 100k.
Regards.

[Young Farmer]

A friend of mine is a salesman for Fuchs oil( formerly Silkolene and Century) and he contacted Fuchs technical department for an answer to your dillema.
Their answer was that modern gear oils do not contain corrosive additives and will not affect brass bearings They recommend their BOA 80w-90. Hope this is of some help
Dave

[s-type]

A friend of mine is a salesman for Fuchs oil( formerly Silkolene and Century) and he contacted Fuchs technical department for an answer to your dillema.
Their answer was that modern gear oils do not contain corrosive additives and will not affect brass bearings They recommend their BOA 80w-90. Hope this is of some help
Dave

Cheers Dave, do they recomend their GL4 or their GL5?

I have just found on line the Laycock overdrive manual, it says to never use EP oils in the overdrive as the EP properties are bad news!

[scimagain]

You may have started something with this one.
From trawling a few sites it would appear that Laycock (GKN) did advise the use of 20/50. The problem comes when you look at the car makers sites (MG, Triumph, Reliant etc.) they recommend EP80 grade. The argument is that GKN say that EP 80 is not suitable but the car makers found that 20/50 was bad for their gearboxes. Tough call when you have a common supply.
One theory that appeared (on an American site) was that when they tested each type in the same gearbox, they found that the oil pressure in the O/D was so high when using EP it caused the gears in the O/D to lock up. They quoted the fact that (in their opinion) the EP was too thick to flow readily through the small oilways.
Personally I'll stick with EP80, it's been in use in my type of gearbox and O/D for many years and has not created any problems. I think the majority of the British makers chose EP for their own cars.
You pays your money and takes your choice?
What does your car club suggest?
PS it would appear that the GL grade you are looking for is GL4 - if ,of course, you go down the EP route.

Regards

[s-type]

....but the car makers found that 20/50 was bad for their gearboxes. Tough call when you have a common supply.
Regards

Hmmm, this point is very contentious. Because Jaguar recommend 20/50 (well SAE 30 at the time) for the early “moss” non syncro gearboxes, used until 1965. Then from 1965 they say EP90. Now, we know that 20/50 works fine in gearboxes because its recommended on MGB’s (syncro and non) as default and many other classics. We know 20/50 does not damage the syncro and I can not find anyone anywhere saying it wrecked their overdrive gearbox. I can however find loads of people, including Hardy engineering and a big American Overdrive place (the one you quote) saying don’t use EP90. I can also find the A series Laycock manual saying DON’T use EP90!!!
What I can see is that if you do use 20/50 it must be a low detergent like Castrol Classic XL.

As we both say, you pays your money and you takes your chance!!!!!