Gearbox oil

[Gmg31]

just drained my gearbox oil and wondered what members recommend as a replacement. just searched my workshop manual and can't find it. Ive got some Mobil 85w90 from another project.

[4129R]

Standard 80 manual gearbox oil. It takes about 2 litres.

It takes a while to drain out of the bottom, so go make a cup of tea or coffee while it is still dripping.

[Jesspo]

I use a transaxle oil for my 365 gearbox, Castrol Syntrans Transaxle 75W-90, for the 365 the filling is 1,6l

[Gmg31]

Thank you, Im leaving  it overnight

[BDA]

I like Redline 75W90NS. When I first got my car on the road, the NG3 I got had a rough shift into 2nd gear. I took my car to a very good shop (they restored Mario Andretti's Alfa F1 car, they prepare vintage race cars, and they work on high end sports cars like Ferraris and Jaguars... you get the idea). When I told him about the rough shift, he said to use Redline oil. I didn't believe him, but after I asked a couple of others who agreed with him and then changing to Redline and it smoothed out, I'm a believer now. It's not cheap, but I'm sold.

[Grumblebuns]

Resurrecting an old thread here.

In topping up the oil in my 336 gearbox, I used up my last half quart bottle of Castrol 80W/90 Hypoy C gear oil, the gearbox is still not topped up and none of the local auto parts stores carry Castrol gear oil anymore. I'm wondering what peoples thoughts are on mixing gearbox lubricants. I do not know what the previous owner used in the 336.

After thinking about this, I've decided to drain the gearbox of the old oil and refill with Redline 50205 synthetic MTL 75W80 GL4 which I've already ordered.

Joji Tokumoto
Fallbrook, Ca   

[jbcollier]

Oils are designed to be ok to mix with other oils of the same rating.

[Grumblebuns]

Thanks. Not knowing what the previous owner used in the 336, I've decided to drain and refill with the Redline. 

[Gearbox]

I have always used Redline MTL in my Elan's gearbox and it works great.  But the warning is not to use it in the diff as it uses Hypoid gears and the Redline 75W90 GL5 is the one to use.  But isn't the Diff in the 365 a Hypoid gear?  I also found this on the web on http://www.syncro.org/Oils.htm :

DO NOT use REDLINE in the transaxle We used to recommend Redline oil for the transaxle based on the advice of Redline techs and on the advice of rebuilders. Redline has since changed its formulation (removing zinc compounds) and the rebuilders have concluded that Redline use now contributes to premature ring and pinion failure, especially if you have an engine with more power and torque than stock. Thus, it is recommended that Redline not be used in the transaxle.

The recommendation from this site says to use Swepco 210 oil and even as a GL5, it does not contain any harmful or corrosives chemicals to our older syncros.  Apparently GL4 is the safe oil for our cars and most GL5 oils have these harmful ingredients. 

According to the factory manual, the gearbox oil should be 80 weight gear oil like the Castrol Hypoy Light or Shell Spirax 80, so basically a Hypoid oil because of the diff ring and pinion.  So I am not so sure if MTL or MT90 is the way to go in these transaxles. 

I'm still searching for more information, so if anyone has something to add, please feel free to chime in.  Thanks Allan

[jbcollier]

There are hypoid final drives and there are hypoid final drives.  Many US solid axle diffs had their pinion gear so low it was practically falling out the bottom.  The stress on the diff gears was enormous and they even chewed up special oils in short order.  Some transaxles also have a the pinion gear offset from the ring gears centre line by quite a bit and the use of hypoid gear oils is VERY important.  It is also true that the Renault transaxles use hypoid final drive gears.  However, all that said, the pinion is only very slightly offset from the ring gear's centre line so any increase in stress between the gears is minimal.  Finally, people have been using the non-hypoid gear oils in the Renault transaxles for decades with no problem.

Here is cross section of a 336 transaxle showing how the pinion aligns with the ring gear:

http://www.lotus-europa.com/manuals/s2work/f/big/fig4.jpg

[jbcollier]

As a comparison, here are two cross sections of typical hypoid diffs:

http://machinedesign.com/site-files/machinedesign.com/files/uploads/2015/04/Hypoid%20Gear_2_0.jpg

https://upload.wikimedia.org/wikipedia/commons/d/d1/Sprocket35b.jpg

As you can easily imagine, the increase in stress is enormous as the teeth "wipe" across each other.

[Certified Lotus]

I have been using Red Line MTL for Elan gearbox and 75W90 gear oil in the diff for years. I was hoping that I could also use in the Europa.

[BDA]

Great information here! As I stated above, I've been using Red Line but what I didn't say is that I also asked Red Line for their recommendation for oil in a Renault Fuego (I have an NG3) and they recommended their 75W90NS. Of course, they aren't going to recommend a competitor's oil and their recommendation may not be good. However, I am looking at the NG3 manual and the pinion is almost in the center of the ring gear (not surprising since the 365 and NG3 are essentially interchangeable). As John noted, the real question is just how "hypoid" the ring and pinion are. I'd say we Red Line users are in good shape and that you're safe using any appropriate gear oil so I think we can breath a little easier!

[Gearbox]

I brought up this subject as I was about to go through my 365 transaxle and started to look into recommended oils.  I'm a big fan of Redline and almost use it exclusively in my race cars and vintage cars like most of the people on this site, especially in our Elans as it does make a difference.  But on my vintage Porsches, the community believes that the Swepco 210 is the oil of choice.  And it is a synthetic hypoid oil.  Needless to say, with the limited use that these cars now have to undergo, I think the Redline would be fine, and the points everybody makes does sound reasonable.  But a few things are still sticking in my head:

1)   Redline warns that the MTL and MT90 oils are not to be used with hypoid gears.
2)   A non marque gearbox only forum indicates that while it was ok in the past to use Redline MTL and MT90        in transaxles, it is no longer recommended as they removed the zinc from the formulation and it was found to cause damage to the ring gear and pinion.  I have to assume the zinc allowed the gears to swipe easier.
3)   Redline recommends the use of their 75W90NS which is a Hypoid oil for the Renault Transaxle and not the MTL or MT90.
4)   Factory specs is for a Hypoid oil.

So now with this said, I fully understand and agree that the Renault transaxle has less of a swipe across the gears. But it still does have some.  And again, with the miles put on these cars it most likely does not matter, maybe.  But since the Porsche community has been using the Swepco 210 product in their transaxles for ages, and the fact that it is a hypoid oil, I think the safer bet would be to just use the Swepco product or the Redline 75W90NS, especially with the change in formulation with the Redline MT products.  But as of this point, I think I will be using the Swepco product as it is in my vintage 911's and later Porsches.  Just saying.  Thanks Allan   

[Certified Lotus]

Thanks for all the research Alan. You convinced me and I ordered a gallon of Swepco 210 ($87 on Amazon).