Transmission oil specs

[Mark]

I use lucas 80W90 gear oil

[rupert's]

I'm a bit confused ... I think I remember that a long time ago I saw in another forum conversation that the right oil was GL5, now I think I understand in this conversation that GL1 is better

Soon I will make a change to transmissions and differentials, now I have 80W90 API-GL5 / MT1 - DIN 51517
Should I find another oil that is GL1?
Greetings to all

[rickf]

What you are using is just fine, As long as it has the MT-1 modifier then there will be no problems. The original GL-5 had issues with deterioration of the brass in the transmission, Once they found this out they added the MT-1 modifier and that solved the problem. As long as you use a good brand name oil you will be good. Stay away from no name cheap oils. If you are still uneasy about it just go with GL-4, there were no issues with that and the GL-4 is still a modern oil with all of the modern additives.

[rupert's]

Perfect Rickf, everything cleared up.

[svramselaar]

hi

see my text before
use only GL1 at the grearbox
if you want to see how synchromesch rings look as the worn out use GL 4 or GL 5 you will see them

https://www.penriteoil.com.au/knowledge ... -oils/1036

MT-1 stands for manual gearbox see text

george

[rickf]

That is interesting George. I am really curious to get Raymonds take on this considering he is in that business and has all the schooling to go with it. I know the GL-1 is no longer supported nor is it tested so it can have anything in it, or lack of anything............ And that is what worries me. Oil companies are not going to spend money on quality ingredients on something that they know is no longer tested and only used in tractors and low speed equipment for the most part. But the MT-1 modifier, at least in this country, was put in there to solve the problem of metal erosion or syncros and bushings. At least that was what I was led to believe. I have been using it for a long time in several manual transmissions and have never seen any indication of metallic in the oil or degradation of shifting.

[raymond]

Shell also sells this:

https://shop.sclubricants.com/shell-spirax-s6-gme-50

It is specifically made for manual transmissions, but might be hard to find. It used to be sold under the name Dentax S 50. The Dentax formulation was specifically made for manual transmissions and had a API GL1 through 3 classification. It was not a big seller for us as most road tractor transmissions have a 500,000 mile or longer drain interval. Smallest size we carried it in was 16 gallon.

Shell eliminated this line as well as the Donax line (which contained their automatic and hyrdrostatic transmission oils) and rebranded it all under the Spirax line. This was all done after I quit working at the company on a regular basis.

Here is a link to the specs of the former Dentax S 50 oil.

https://theindustriallubricantstore.com ... t-5-gallon

It is virtually identical to Spirax s6 50


https://www.mil-specproducts.com/Docume ... gme_50.pdf

Bottom line is that the MT1 standard involves a strip of pure copper for the corrosion test. Pure copper is more prone to corrosion than brass alloys involved transmission synchronizers.

If you are still worried, try and buy some 50w transmission fluid. Or use 50w heavy duty diesel engine oil. This is what we used at the company when I was a kid when the switch from GL3 to Gl5 occurred. Back then, we started using Shell Rotella 50w motor oil in our road tractors and straight trucks. We later switched to Dentax 50 and switched to (synthetic) Dentax S 50 when manufacturers started offering longer drain intervals and extended warranties if we used synthetics.

I personally will not use API GL1 through GL3 oils as they tend to be sold under unknown private labels and also are no longer tested for compliance to specification.

[tbh726]

So i am ready to change the oil in both the differentials and transmission. there is a great deal of information in this thread, but for a noob like me on this subject i am confused. so for my A2 truck do i use the one in the picture that someone said was ok, but then someone else said it was not good for differentials. i am second guessing what to use.

tim

[Hambone]

There is a good write up in the Wiki.
wiki/index.php/Transmission/Transfer

[rickf]

As much as I have been pushing for the wiki to be absolutaly accurate I see that is one thing there that will need to be changed. Modern times mean things change. Raymond, who happens to be in the oil business, has pointed out that the old GL-1 designation is no longer supported nor is the oil tested for accurate properties. Chances are it would not harm anything and I use it in my tractor all the time. BUT, my tractor does not have 4.88 gears running 55 mph down the road!!!!! Those gears are screaming and if anyone of you has ever touched your rear differential after a long ride it is something you will not do again too soon, it is HOT! I only use modern gear oil in mine, 85W-90. I have been using the GL-5 with the MT-1 additive for 5-6 years now and I have had no issues at all with my synchronizers.