i drained hypoid oil out of my transmision and put in redline mtl. it is not quite as heavy as the 80-90 recomended, but really smoothed out my transmission. the previous owner put in some kind of hypoid oil and it crashed in every gear. now there is only a little crunch in second during cold weather.
I have some shell spirax I am going to try, since that is what Alfa recomends.
cliff

 

i drained hypoid oil out of my transmision and put in redline mtl. it is not quite as heavy as the 80-90 recomended, but really smoothed out my transmission. the previous owner put in some kind of hypoid oil and it crashed in every gear. now there is only a little crunch in second during cold weather.
I have some shell spirax I am going to try, since that is what Alfa recomends.
cliff

Isn't the MTL a "very watery" viscosity?

 

The shop manual says 87 spider gerbox requires GL-5, then you do the research, and learn the gL5 is mainly gl4 with additives, mostly made for HYPOID gears, which have nothing to do with the gearbox gears, as the hypoid gears are in the differential, right (cautiously asking, hoping for agreement).

So what is the big deal with gl5, if, when you look at what, say, IAP offers, they advertise that "later than 69 alfas need GL5", then go on to explain that Spirax 80-90HD GL5 does not have the aditives that can ruin synchromeshes.

How can you make sense of it all? If you say the spec is GL5, then turn around and say Spirax is GL5 but without additives, when GL5 is basically WITH these additives , made for the hypoid gears, which are not even in the gearbox!! That is contradictory.

It is a mess. I am considering using GL4, as it is , in my research, recommended for MOST manual transmissions, and for extending synchro life.

I've also been slightly perplexed by this also. GL5 as I understand it, contains sulphur additives which aren't good for syncro's but was made especially for "rear ends." Spirax is GL5 which theorically then wouldn't be good for the gearbox unless maybe the syncro's aren't made of a metal that would be attached by the sulphur. Brass syncro's don't like sulphur so those gearboxes should use GL4. I know on Chevy forums they state emphatically that GL4 gear lubes should be used in Muncie transmissions and ditto for Nissan transaxles. GL4 isn't the easiest stuff to find nowadays. MT90 syn Redline is GL4 and my Nissan transaxle proceeded to start dripping from the axle seal shortly thereafter I started using it. I sent away for some Penzoil GL4 dino gear lube which I'm using as a fill to the Nissan transaxle and it has slowed the leak considerably. I also use the Penzoil GL4 in my Muncie 4 speed gearbox. All this being said, I've got Spirax GL5 in my Alfa trans. which everyone says is apparently OK.

 

no, it is 75w something, only a little thinner than the 80w90. possibly you are thinking ot the lube similar to automatic transmission lube popular with newer cars.
cliff

 

no, it is 75w something, only a little thinner than the 80w90. possibly you are thinking ot the lube similar to automatic transmission lube popular with newer cars.
cliff

That was it, thanks

 

I am now confused. Some additives such as friction modifiers can be required to work in some geared devices, but I am not really sure if that is the reason behind this....

 

The confusion stems from the preference to use Redline synthetic oils. For the differential Redline 75W/90 is great. It contains EP (Extreme Pressure) modifiers. The EP modifiers however, make the oil too slippery to use in the gearbox, as the synchros won't like this. Thus, for the transmission one must use synthetic Redline 75W/90 NS. The "NS" (Non-Slip) being the critical designation, meaning that it does not contain the EP modifiers that make the oil too slippery.

I would encourage a search, as there are a number of posts on this subject.

Best regards,

 

Thanks, Zunige, but I believe this redline ns stuff is shrouded in suspicious "dark science". It cant be the only gera oil without modifiers, as GL4 is just that, I believe. I talked with the tech rep from Exxon 2 days ago, and he believes all the little guys tout their brew to get an "edge", in different words, of course.

If you dont need the modifiers, maybe we should stay away from GL5, then........use GL4. Most sources say GL4 is for MOST manual trans's.

Note: the additives of Sulfur do not harm our alfas as far as corrosion, since there are no "yellow" metals in there(although they may maqke the stuff sliperier.

 

Unfortunately, this doesn't answer the question of using Spirax GL5 in the gearbox.

 

Right. So why do they claim their GL5 does not have the modifiers, if GL5 is supposed to contain them(scratching scalp like a primate, confused).......

 

redline mtl is "Manual transmission lube" it works for me. a lot better than whatever the prevoius owner put in.
cliff

 

I believe the GL1/GL4 designation is for the NON Moly synchro's in the earlier gearboxes.

Alfa Factory spec PA381500000000 for the 115 Spider, which updates the English language workshop manual lists acceptable GL5 lubricants in Dino 80W/90 and Syn 75W/90.

An individual can learn a lot by going to the Red Line website.

The "correct" Red Line oil for our transmission is 75W90NS.

One should bear in mind that we are looking at 20+ year old transmissions, Syn gear oils started to come on the scene not much before that time. Oil formulations even for the same product are much different today (2008).

All oils when reformulated, still need to be re-certified to carry their respective SAE and API Classifications.

Elio

 

OK, Elio, you are Hillary, and I am Barak, and "you were my friend before this thread, and you will still be my friend after this thread"....LOLOLOL

I have been on that redline site, and it is kinda scant as far as specifications/additives go. They cant be the only ones making a gear oil for our alfas. Industry/business doesnt work that way. They are dispelling "dark science" to the point of having duped the alfa comunity into thinking they are the only ones that will save our synchros. They are lacking , to me, of objective info, and specs.

Naturally suspicious,
Joe (Giuseppe)

 

Watch out which "experts" you invite.......These experts are the ones that may have caused this confusion with their claims in the first place......

 

I dont know additives or work for any suppliers of oil, I only know I put in redline mtl in the winter of 2005 and my transmission shifts much better in my 74 spider.
cliff

 

I dont know additives or work for any suppliers of oil, I only know I put in redline mtl in the winter of 2005 and my transmission shifts much better in my 74 spider.

cliff

and no leaks?

 

Redline is a good trans oil, as well as for diffs.
BG synroshift 1 and 2 both can substitute ATF and require no additives. There are road race and drag cars using it. I have personaly experience it, and it feels like a trans rebuild lol. No problems ever.

 

Giuseppe, let me assure you you have not and are not about to lose 50% of your italian friends. BTW does your middle name start with an "H"?

Oil chemistry is NOT like analytical and pure chemistry, it is like wine making, certain aspects are dark science.

I would only advise that you put in GL5 spec oil in your trans "project". Whether it is Dino or Syn is your choice, but I would advise NOT to go with GL1/GL4.

(BTW I worked as an instrument engineer in process control in the lube plant, research pilot plant and test plant of one of the major lube oil refiners)

Ciao Giuseppe, snowing up here!, send some Spring please!

Elio

 

Whew (wiping sweat from forehead), glad I still have you guys as friends..LOL.

Hey Elio, thanks for shedding light on the dark aspect of this subject. OK, You convinced me not to use GL4. I will probably order some spirax 80w-90.

(darn, does this mean this thread may die now?)

Just realized I dont have to cover my coffee tree...it froze last month with that 40 degre cold snap..........maybe it will sprout in May??

 

My 2 cents: I just put Redline MTL90 (75W-90) in my spider trans to help with extreme cold weather drivability. It helped. I can change gears in 35F degree weather without waiting for 45 minutes before driving off. I had Spirax 80W-90 before. Both are recommended for spider trans. There was nothing wrong with the Spirax in the summer.
I know that this does not answer your question about the GL4 vs GL5 dilemma, and definetly does not put the issue to rest. I'm not sure that we can find the differences between the two (who wants to try and post the unobjective results?). there will always be some question of objectivity in the research. That's why the issue of OIL, coolant, and brake fluid will not go away.

ps. Nissan was mentioned before, what year and model are we talking about?

 

ps. Nissan was mentioned before, what year and model are we talking about?

Nissan 1991 Sentra SE-R's anyway. It calls specifically for a GL4 and most guys run MT90.
Redline 75W90 GL5+ Hypoid Gear Oil - SR20 Forum

 

How can you make sense of it all? If you say the spec is GL5, then turn around and say Spirax is GL5 but without additives, when GL5 is basically WITH these additives , made for the hypoid gears, which are not even in the gearbox!! That is contradictory.

The confusion stems from the preference to use Redline synthetic oils. For the differential Redline 75W/90 is great. It contains EP (Extreme Pressure) modifiers. The EP modifiers however, make the oil too slippery to use in the gearbox, as the synchros won't like this. Thus, for the transmission one must use synthetic Redline 75W/90 NS. The "NS" (Non-Slip) being the critical designation, meaning that it does not contain the EP modifiers that make the oil too slippery.

The problem is that you guys are confusing the additives. The GL-5 hypoid additives are EP additives (extreme pressure) and are not what mess up the synchronizers. The limited slip additive (a friction modifier, which is not in Spirax or Redline 75W90NS) is what messes up the synchronizers.

Spirax *absolutely* has EP additives, otherwise if you used it in the diff your pinion and ring gears would eat themselves.

There's an awful lot of debate about this subject considering that the factory recommended Spirax is cheap and works well

 

The problem is that you guys are confusing the additives. The GL-5 hypoid additives are EP additives (extreme pressure) and are not what mess up the synchronizers. The limited slip additive (a friction modifier, which is not in Spirax or Redline 75W90NS) is what messes up the synchronizers.

Now I'm confused. A limited slip additive reduces friction and a syncro works on the principle of friction. Would this then not improve the shifting by increasing the syncro friction?
I'm now at a loss as to how to explain why, after draining a hypoid EP gear oil out of an Alfa gearbox that had shifting issues, and replacing it with a non-EP lubricant (50 weight engine oil to be exact) that the shifting issues disappear.

 

Gubi,
Yes, I did confuse the additives... I stand corrected on that description. However, I'm not confused as to the reason why the additive is not good for the tranny, and which product is supposed to go into the differential or gearbox, regardless of this being the factory specified Spirax or the synthetic Redline products...

Best regards,

 

Gubi hit the nail on the head, as usual....

And Giuseppe, the coffee tree will sprout again, only the top that got hit by the cold will die, look for a new sprout and cut off the dead top above the new sprout. What spec water are you going to give the poor thing?

Elio

 

I ran Spirax mixed with one qt of redline for about 150,000 miles in the Milano then went to all Spirax
then I went to all redline ns and then redline worked the best for me.
then I put in a rebult box with the redline.
I have Spirax in the spider and redline in the Milano both with now rebult boxes and lightend gears. and the Milano shifts much better. the Spirax seems to need a long time to warm up. the redline is good to go as soon as I turn the key.

I did run ATF in the spider before I got the new box and it seemed to help a lot. but I do not know what the long term damage might be using ATF. and as I knew I was going to put in a new box I did not care at the time.

 

I have Spirax in the spider and redline in the Milano both with now rebult boxes and lightend gears. and the Milano shifts much better. the Spirax seems to need a long time to warm up. the redline is good to go as soon as I turn the key.

No surprise there - the Redline is synthetic and has a lower winter rating (75W vs 80W) so it's thinner when cold.

 

Papajam, I think the differences are in "slip" or "shear" charachteristics. These are lumped in with the "friction modifier" package.

If the oil is too "slippery" it will not bring the syncros to speed.

You can reduce friction, but in doing so you don't want the oil to be too slippery, the force that drags the synchro.

The Redline has this NS designation (Non Slip? Neutral Slip?) they formulate specifically to achieve that desireable Shear or Slip characteristic, while reducing friction on the load bearing surfaces.

My understanding anyway FWIW. Best regards, Elio

 

Well, I'd agree with you, except that the EP additives don't work by making the oil more slippery, they work by chemically reacting at the point of metal-to-metal contact when the oil film breaks down. So I still don't know the answer for you.

 

Well, I'd agree with you, except that the EP additives don't work by making the oil more slippery, they work by chemically reacting at the point of metal-to-metal contact when the oil film breaks down.

I recall that the EP additive, unlike it's name implies, actually has nothing to do with 'pressure' or film break down but has everything to do with temperature. Temperature as in the result of friction. As temperature increases, like when a syncro is trying work, the EP additive forms a 'barrier' to prevent metal to metal contact. In essence, it increases lubricity. Or colloquially speaking, makes it slippery.
This explains why replacing an EP oil in a gearbox with a non-EP lubricant can result in the syncros starting to work again. One should also note that when Alfa switched the syncro material in 1968, the sticker by the gearbox fill plug was changed to say something like 'do not use EP oil', or words to that effect.

 

...what material are the synchros in the Spider gearboxes made of?

 

They're molybdenum. Everything in the modern Alfa tranny is GL-5 compatible - no brass.

 

Close. It's high temperature at the point of metal to metal contact. If the metal surfaces don't touch then the EP lube doesn't come into play. Good discussion and illustration at the link (taught me a few things, that's for sure):

Oil analysis and lubrication learning cennter

Could this affect the synchronizer operation? Mongo dunno. But if the non-EP works better because you get more friction because you have more metal-metal contact, I'm not sure that's the way you want to go.

I think you've got it backwards on the synchro material: the pre-'68s use non EP (Dentax GL-1), the post-'68s use EP (Spirax). The thread below seems to agree with this.

http://www.alfabb.com/bb/forums/giulietta-giulia-1954-65/11202-transmission-oil.html

 

I purchase Redline products from Jack Beck in Omaha, NE. He used to race Alfas and still builds Alfa race cars, engines, etc. When I bought my '86 Spider last summer I went to him to purchase some oil for the transmission. He sold me Redline MTL. I later read some threads here that had me worried. I called back and was assured that MTL is all he has ever used in Alfa's (at least of the Redline products) and he has had no problems.

 

I put Redline 7590ns in mine. The only time Ive driven it (around the block, on 2-3 cyliners and not-very-good brakes) I had to really slam the gears to keep moving so it wouldnt die and to slow down and such. I didnt have a single crunch and no over-excessive pressure to get it in gear. seems to be good stuff.

 

Whew!! Glad this is cleared up now..LOL

One really needs to be an organic chemist to get all this stuff........

Jake at IAP was telling me a few days ago, that some of the claims the oil companies make should be taken with a grain of salt, in other words, and that the only real way to improve the tranny is to lighten the gears, cuz alfa made them waaaaay too heavy for this little car. (and of course, check rings and all while youre in there). This sounds like the right direction.......

Anyone know someone that can do a good job of this at fair price?

 

...Jake at IAP was telling me ... that the only real way to improve the tranny is to lighten the gears, cuz alfa made them waaaaay too heavy for this little car. ...

Jake's statement, if he really did say this, is one of the most ignorant any person can make regarding an Alfa Spider transmission. I would not ever trust a person with this lack of knowledge, and unfortunately IAP has several sales people that truly know nothing about Alfas. (I know IAP monitors this Board, so I truly hope they read this and correct this most irresponsible spreading of bad information.) By the way, the gearbox is not an Alfa design and it is used by other marques of the period.

Joe,
You should do a search on lightened gears, and you will see some very knowledgeable people weighing in on the debate about doing it or not. (There's a thread started by bianchi1 that I remember.) A couple of points, just to get you started. There is very little that can be and is removed to lighten the gears. Some knowledgeable people say that you cannot tell the difference between a gearbox rebuilt with standard gears and one with lightened gears, and that just the rebuild is all that is needed. Some will say that going to this extreme is what racers do to reduce every ounce of weight. Others disagree and say that it really does improve the shifting and you can tell the difference. All agree that there is no harm in lightening the gears, and that if it is going to be done, to do it when the tranny is going to be rebuilt. Certainly no one suggests opening a gearbox that is in good working order to do this.

From personal experience, I can tell you that I have always wanted to do this to my gearbox. However, I drove one of my Spiders 4+ hours to an Alfa outfit that specializes in this type of work. They test drove my car for a few good miles, and then refused to open my transmission to do this, as it was in good working order. I give them a lot of credit for this, as they support a lot of customers who are into performance and racing. When the time comes, they will get my business.

Best regards,

 

Thanks, Enrique! I appreciate your candid perspective, and now I have a good excuse not to drill holes into my gears. I can understand racers wanting to obsess over miniscule factors, etc. But I am not a racer....have too much respect for machinery for that....LOL!!!

Jake was trying to help, I dont really blame him, but, I guess one must weigh every opinion one gets. But, as you suggest, drilling holes may be a last resort. Inabout a half hour, I will drain my oil and add a clean GL5 80-90. But I am guessing it will have to come out next month, or so.

Lightening gears does seem like extreme. And expensive, Im guessing, as it has to be done right. (Why is it that alfa has so much troubles with their trans??) My sunbird has 152,000 miles, never had a problem with it. Oh well.........