Synthetic or semi-synthetic oil by Tony Lloyd -- The use of a Synthetic or semi-synthetic oil in the gear box really does improve the gear change making the box much smoother and easier to select gears, particularly 2nd from cold. The oil I have been using is Castrol Syrtax which is available in 500ML containers (6 of these are needed for a Monte box) Don’t forget if you drain the gearbox there are two drain plugs, one in the gearbox housing and one in the differential. There are of course significant benefits associated with the superior lubrication qualities of synthetic oils in both engines and gearboxes
Subject: Re: tranny fluid From: stuart@hal.com (Stuart Hastings)
> What is the proper tranny fluid for a 78 fiat spider what will happen if a modern fluid is used such as a API GL-5 It says in my owners manual to use a non ep fluid what does it mean by EP
Oh No! Not the Dreaded Transmission Oil Subject Again!! (Sorry. The italian cars list has entertained some very extensive discussions on this subject. Many people have opinions, and nobody was able to persuade anybody else anything; we all *know* we're right, and everybody else is crazy!)
Expect lots of different opinions on this. Many people say that GL-5 is literally "too slippery," preventing your synchro rings from syncronizing, and promoting wear on the synchro gear teeth (Vandor @ Caribou).
Some people say EP will attack and corrode the synchro rings (don't recall who).
Some people say the EP additive in GL-5 will hurt your transmission bearings (oil wholesaler, and my experience).
Some people say GL-5 works fine in FIAT transmissions (Obert & Co. at FIAT PLUS).
"non-EP" means no "Extreme Pressure" additive in the oil. EP is added for the benefit of the "worm gears" (ring & pinion) in rear axles. The mating surfaces of these gears slide across each other, and these gears will wear out quickly without the EP additive.
I asked an oil wholesaler once, and was told that EP is really lead sulfide. The theory goes that worm gears naturally grind themselves away in operation, and lead sulfide will assist the worn-away bits of gear teeth to "re-weld" themselves back onto the worm gear teeth (presumably while under Extreme Pressure). Bearings supposedly don't like EP in their oil, so rear-axle bearings are made bigger or tougher so they will tolerate it. The theory sounds really crazy, but rear axles will destroy themselves very quickly if EP isn't present in their oil (somebody tried this in an Alfa differential).
Your transmission has no "worm gears." If you study your owner's manual, you'll probably find that FIAT specified EP oil for your rear axle differential, and non-EP oil for your transmission. Since FIAT has made this distinction, you may find it worthwhile to honor it. Some people say that GL-1 is available at NAPA stores. I haven't checked. RedLine also makes a suitable oil, but it is very expensive.
If you have trouble locating GL-1 in your area, look in your yellow pages under "Oils-Lubricating" and call around. I get mine from a local oil wholesaler in five-gallon buckets; they call it "Mineral 90."
Good Luck with your FIAT,
Stuart Hastings