GL-1: Long story short(er)

Bob S

Bob S

1974 X1/9 owned since '77
... wanting to change trans oil this weekend on my '74 X ... I found one of our preferred suppliers was out of stock on GL-1. Previous discussions on this board recommend Redline MTL or MT90 ... but having seals in this trans that are from the 1980's ... I decided to not go with synthetic as it would leak more (just a few drips currently) than non-synth according to trusted source MadMatt. Debate amongst yourselves 'bout that.

A-n-y-h-o-w, fast-forward: Searched net for a long time and followed up on many dead ends including a GL-1 manufacturer StarBrite that gave me names of boating stores that carried their product ... but none knew of it.

Last resort, looked on Midwest124 site and saw on home page that he recomended GL-1 and that NAPA carried it. Called two NAPAs and both said "huh? We got GL-5"

Then via email request Midwest124 gave me a stock number for 5-gal and from the msds sheet I was able to track down the 1 gal p/n. TaDa! Here are the stock numbers for Napa 90 GL-1 Gear Oil. Can be ordered from any dealer ... and I even found a local dealer that had it in stock ... and just $8 for a gallon, enough for a complete fill on the X.

NHF65201 (1-gal)
NHF65205 (5-gal)

http://tinyurl.com/d34j4o
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Why?

Why would you use GL1 when there are excellent petrolium alternatives. 20w50 Motor oil is an excellent substitute and works way better than GL1. Nor will it leak more than GL1 in those 30 year old seals.
 
stupid question time

I am trying synthetic motor oil (10w-30) for the first time. Does this mean the engine's gonna leak more than it already does?
 
Thanks and a Question

In our local Fiat Club we have a lot of Fiat Spider owners what Trans oil do you recommend they use? Oh and what Trans oil for my 850 friend? Thanks
 
racerx said:
In our local Fiat Club we have a lot of Fiat Spider owners what Trans oil do you recommend they use? Oh and what Trans oil for my 850 friend? Thanks
Click to expand...

I ran 20/50 motor oil in my 124 Coupe and Spider. It works great. Should work fine in the 850 too. But Redline MT90 is probably the best for either app.
 
Why?

Guess this is one of those topics that can start a bar fight! As long as Midwest X1/9 and Midwest 124 both put GL-1 at the top of their list for an older trans ... AND I was able to find it down the street .... I'll give it a try. BUT at least all those in-the-know seem to agree that if you have some leaks and drips ... you will have MORE with a synthetic.

I'll let y'all know how it runs on a fresh gallon of GL-1

Steve- Is there a simple explanation why GEAR oils are even made if regular motor oil can be used with no disadvantage?
 
I just change mine also

But I went with Amsoil 75/90 gear lube. I don't think that the tranny has been change in a long time it came out black as coal with a lot of metal flakes, not good :eek: Maybe that's where my reverse is or why it won't stay in gear when backing up need to feather the clutch and gas while holding it Reverse. Not as bad now with new oil in it but still it looks like a rebuild is in order or get one from Matt.
 
A good reverse is the interaction of the reverse idler gear, the reverse "gear teeth" that are actually on the 1-2 shift slider's outer circumfrence, and the reverse gear teeth that are machined into the driven shaft.

From recent experience I can tell you that "retail" prices for the reverse idler gear can be as much as $75, the 1-2 shift slider as much as $150, and the driven shaft can be either $200-250 or unobtanium, depending upon whether your 5th gear is keyed or splined to the driven shaft.

And you have to be careful if you decide to buy cores in the hopes of mixing and matching...the last edition of the X1/9 5-sp used a slightly larger diameter reverse idler gear shaft, which not only means the gears are different it also means the cases are different!
 
I bought a 5 gallon pale from ...

About 11-12 years ago I bought a 5 gallon pale of GL1 from Walmart. It was called SAE 90 Mineral Gear Oil and is marketed for tractors and fleet vehicles. The part number on the bucket is 5314. Now it might be called something else like "Super Tech" and **might be** made for Walmart by Penzoil. Here's a sku I got off of the Internet - 7874213208.

Best regards, Chris
 
Why GL-1 ????

Yes, this was spec at one point in FIAT history, since then, lubrication technology has move on and advanced in many ways. These days, Synthetic lubricants are used in ever car, machine tool and mechanical object in our shop. Narry a problem with any of them. This includes a 1957 Triumph TR3 that uses rope seals in the engine.. The 1997 Miata had Dino oil for the first 10 years of it's life and was changed to synethic, no leaks.

Gasoline engine oils today have reduced levels of ZDDP and are formulated differently from years ago. I do recall a rather in-depth discussion about this topic on X web a while ago.

Years ago, BMW owners complained about stiff gear shifting in cold weather, so BMW issued a service bulletin to over to W20-50, this helped significantly, but their warranty claims on transmission problems went up.

The factory manual for my SAAB 9000T specifies W20-50 engine oil for the transaxle. The original transaxle lasted ~180,000 miles, and died, 5th gear dissolved and the bearings were shot. A rebuilt was insalled except this time filled with Red Line MTL, It's gone near equal the miles of the orginal transaxle and is still shifts nice with nosigns of excessive wear.

If you are concerned about leaking transaxle seals, change them. It's not that difficult to do.

I' m not trying to criticize or insult or be critical, I'm just trying to understand why one would choose GL-1 today when there are better choices available today.
 
Bob... I'm not Steve... but a simple answer is...

Specific lubes such as MT90 and MTL have "secrfet ingredients" that assist the syncros (dare I say, "provide FRICTION qualities") so that cog speeds can be better matched for smoother shifting, all while still providing excellent lubrication and cooling capabilities.

Not being an engineer or rocket scientist... I have installed MTL in three tranmissions and have noticed GREAT improvements after only a 100 miles or so. Two of the transmissions had not been rebuilt... but felt like they had new syncros installed within a half-tank of gas... and a better all around feel while shifting.

I useta be known around here as Mr. Frugal... so it takes a bit outta me to spend, say 40 bucks, versus 10 bucks for typical gear lube.

I use MTL and recommend it highly... and I would install it in an otherwise good trans that leaked a bit too. The gains would outweigh the drips, IMHO.
 
Agree with Tone-nay...

...who cares if the Redline drips a bit!
The improvement in shifting quality
far outweighs leaving a "red spot".
I've put it in multiple trannies,
and have always seen improved shift quality.
Even in a tranny that shifted perfectly with
whatever gumbo was installed by PO.
Even in a Porsche transaxle that had suffered abuse.
Like a tranny rebuild in a bottle.
MM
 
Ha! (as Tony would say)

Had thought about responding to Tony's post with pretty much the exact sentiments, but lacking the prose. But "transmission rebuild in a bottle" did come to mind.

Works wonders on BMW 'boxes as well. First found it trying to solve a crunchy second gear downshift until the 'box had warmed up completely. MTL worked so well I've recommended it ever since.

I understand Swepco offers something that works even better, but I've not tried it so I can't comment either way. Wonder if Steve H has.... Most likely has, knowing him, yet he still comes back to MTL or MT-90.

Regarding the concern for leaks, the oil makers claim that's an old wives tale. I've been lucky in that installing synthetics in older engines/transmissions/differentials has not seemed to cause leaks. Occasionally might add a bit to an existing leak, but not always.

My most interesting experience with disappearing synthetics is that Mobil 1 motor oil seems to get consumed quite a bit quicker than other synthetics. Had heard this before but didn't realize the difference until Mobil reformulated 1 and I switched to Rotella T Synthetic. Oil consumption on the daily driver 140k mile Benz went from 3+ quarts per 5k miles to less than one quart, with virtually no leaks using either oil.

In other words, what Tony and Mike said...

///Mike
 
I agree...

I agree and use synthetic gear lubes in all my cars. Modern oils are the way to go most of the time.

When I bought the bucket of GL-1, my Yugo had a hole in the inner CV joint boot and I didn't feel like fixing it in 20°northeast winter weather. I kept the bucket with me and would pump some in every couple of days. It entertained my co-workers doing this in the parking lot at work during snow storms.:laugh:

In my X1/9 that's been sitting for a long time, I'll will probably use conventional motor oil but will use MTL in the trans because these transmissions need all the help they can get.

Best regards, Chris
 
Just one more

On the pedestal for Redline. Changed it out in my 28K miles X and almost instantly felt the difference. Much smoother shifting.
 
Bob Shutan said:
Guess this is one of those topics that can start a bar fight! As long as Midwest X1/9 and Midwest 124 both put GL-1 at the top of their list for an older trans ... AND I was able to find it down the street .... I'll give it a try. BUT at least all those in-the-know seem to agree that if you have some leaks and drips ... you will have MORE with a synthetic.

I'll let y'all know how it runs on a fresh gallon of GL-1

Steve- Is there a simple explanation why GEAR oils are even made if regular motor oil can be used with no disadvantage?
Click to expand...

I'm not Steve and hope I can make my point without starting an argument (it seems hard to do and is the reason I don’t post much) but I can tell you why they make gear oils and why they make motor oils. Simply put manual transmissions have vastly different requirements than those of motors. All oil starts out as a base oil (70-95%) and then additives are put into it to make it GL1 or 10W-40 etc. Motor oil additives are primarily focused on dispercency and detergency with consideration to anti-wear and oxidation as well. A manual transmission oil additive pack would focus on friction control and corrosion inhibition more than anything else and have no dispersancy demands at all. For these reasons I would not recommend using motor oil in a gear box that wasn’t design for it anymore than I would recommend running ATF in your motor.

It is no small task to develop these additives either. There are PhD chemists that have dedicated their life’s work to formulating these additives and it is a highly technical and field. Anecdotal data points are nice but I’m sticking with science. If you want an anecdotal data point for GL1, my ’74 has 109,000 miles on it and I have all the service records from day one. All it has ever had is GL1 and it shifts like new and doesn’t leak. The negative is that it is stiff as hell when it hits about 40 degrees outside.

As for the leaks…
“Synthetics” are generally oils made from Polyalphaolefins (PAO) base stocks. There actually are different definitions of what constitutes a synthetic so what we call a synthetic (maybe an API Group III based oil) may not legally be synthetic in Europe. Anyhow, the reason they tend to leak in certain applications is that the seals were not designed with Polyalphaolefins in mind. Generally, mineral oils swell the seal materials slightly due to the aromatics in the oil. The engineers know this and design the fit of the seal to the shaft taking this into account. Often, PAO’s don’t have these aromatics so the seals don’t swell and therefore, don’t seal properly.

One last thing is that these classifications such as GL1, GL4, GL5, etc are performance based rather than formulaic. In other words, it’s not like they are dusting off a 30 year old formula to make GL1. It’s simply a performance classification that was defined 30 years ago.
 
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