USE NON EP GL-1 gearbox oil in your 124

Tech chat w/ Marc Matzer
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Marc
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USE NON EP GL-1 gearbox oil in your 124

Post by Marc » Tue Oct 10, 2006 9:02 pm

The reason for Fiat gearboxes needing non EP gear oil or GL-1 rating, is that GL-5 oil will cause you alloy brass syncros to pit and corrode.
Penzoil makes a "Syncromesh trans fluid" for GM and Chrysler specs.It is the correct fluid for our gearboxes.I called Penzoil and spoke with an engineer at Penzoil about our needs.He recommended this product for Fiats.It is readily available almost anywhere.
The label does not mention GL-1 specs,only the GM and Chrysler spec numbers.It does however mention it is suited for Syncromesh brass and copper based alloys like in our Fiats.It is a non high pressure oil like GL-1.To be sure I called Penzoil and confirmed this.Hope this will save us time and money looking for the stuff as it is hard to find anywhere.Stay away from synthetics in your gearbox,its great for the motor,or rear.It is not good for the Fiat gearbox because of flow and coating characteristics.The gearbox in a spider was designed in the early 1960's based around the GL-1 spec for not only the syncros, but on flow and coating of the parts.
Last edited by Marc on Thu Jan 10, 2008 4:44 pm, edited 2 times in total.

ventura ace
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Post by ventura ace » Sun Oct 14, 2007 10:04 am

Any experience with Valvoline Racing VR1 50 wt motor oil (in the gearbox)? I have heard that this makes a good substitution for the GL-1. This is what I put in my freshly rebuilt 1438cc tranny last week, and wanting to get a good warm fuzzy that I'm not hurting anything. Feels good to drive so far (120 miles).
Alvon Elrod; Ventura, CA
'70 124 spider, mod 1.8L

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allenlofland
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Post by allenlofland » Sun Oct 14, 2007 6:25 pm

I would suggest a WARNING USE AT YOUR OWN RISK under these kind of suggestions. Some of our trannies seem to work well with red line products and then there is the mobile product that also falls into the proper specs for our cars BUT bottom line. GL! is the only factory authorized spec and also I might mentionl what works in one will not always work in another.
Point in fact. Mobile oil that was thought to be great for our trannies turned out to be just to slippery and did not stick to the upper gears, I would wonder if this might not be the bottom line with the Penzoil stuff. BUT simply be aware that GLI is readily available at Walmart and other places you just have to look.Also our vendors sell the right stuf .. Try the modern brews and make your own decissions. I tried several many moons ago and ended back with GLI in all three Fiats :) Just my 2 cents worth
Allen & Lynette Lofland
Wichita Kansas
Back on Land with Our Fiat :)

ventura ace
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Post by ventura ace » Sun Oct 14, 2007 9:05 pm

Thanks for your input Allen, but I've been down that path somewhat already. I put GL-1 (from Vick's) in a transmission after I rebuilt it a few years ago. It was very notchy to shift when cold (though better when warm), and got progressively worse as I put on more miles. After 10,000 miles, I changed to new GL-1 (from Bruce's), and was quite bothered that the shifting was even worse with new GL-1. It was extremely notchy at any temperature.

Knowing that I would be pulling the tranny soon to take care of a leak, I experimented with regular EP 90 wt gear oil, and found that the tranny shifted really smoothly -- even though I know that this is not recommended for the brass/copper synchros. The EP 90 wt gear oil behaved magnitudes better than GL-1!!

I put the Valvoline 50 wt racing motor oil (equivalent to 90 wt gear oil) in after this rebuild, since I didn't want to go through a similar experience with GL-1, and didn't want to use an EP oil, and had heard or read good results with the 50 wt racing oil from a few sources. That is why I am posting here, to see if there are others with good / bad / mixed results with Valvoline 50 wt racing motor oil.

Again, thanks for your inputs Allen. I don't doubt that you, and others, have had good results with GL-1. I, for whatever reason, have not been that fortunate.
Alvon Elrod; Ventura, CA
'70 124 spider, mod 1.8L

rpconlon
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Post by rpconlon » Mon Oct 15, 2007 10:35 am

Alvon:

I believe that enough tests have been done with high quality motor oil to indicate that it is an acceptable substitute as is the Redline product.
GL-1 is not hard to find as Gear Oil at common autostores if you read the labels. I found it by the gallon at Autozone and use it.
I do find the shifting is stiffer when cold if I try to shift below 3000 rpms but above that and cold seems to operate smoothly and more so after a minute of running with GL-1.

Cheers
Ron
Ron Conlon
2016 Fiat 500 Sport
Ottawa, Ontario
Canada

Marc
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Synchros

Post by Marc » Tue Feb 19, 2008 8:23 am

Fiat synchros work based on friction.Many oils out there are too slippery for our application.Red Line MT-90 is an oil that will work and has the correct additives for proper synchro engagement.Long term,the jury is still out.I've tried it and had selecter forks suddenly wear out,could be a coincidence.I run synthetic in everything else.Regular Gl-1 in the gearbox
Worn shifter forks, sliders and worn teeth on the synchro sub-assemblies will cause all kinds of engagenent issues when cold,Parts get hot expand and take up slop in the parts ,so it gets better when its warmed up.

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juppy
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Post by juppy » Tue May 20, 2008 10:22 am

rpconlon wrote:I do find the shifting is stiffer when cold if I try to shift below 3000 rpms but above that and cold seems to operate smoothly and more so after a minute of running with GL-1.

Cheers
Ron


I just changed over to this stuff...

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Closest I could get to the ZC90 that FIAT recommend on the non EP boxes that most FIAT's used here until the 90s. Weirdly it's nearly non existent at FIAT dealers now and you never see it in auto stores :cry:

Not sure that the panda is 'Vintage' thou LOL (but the spec is right)

I'd been using engine oil in the box and swapping to the thicker oil was quite a shock as Ron says the box is much stiffer when cold and changing down to second needs a bit more for thought than before....

Jim
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