Technical seicento 899 gearbox/oil spec

[rehtnap]

hi
i know there is a lot said about oil types im just curious as to what people find the best to run in a 899 seicento gearbox. now as i understand it the seicento 899 box is the same box as a cinquecento. the cinq started off with a ep 80 spec oil.when it got fitted to the seicento it crept from a 75/90 gl4 to finally a gl5 spec. does anyone know if the internals were altered or was this a case of fiat just specing the latest oil. also they spec a fully synthetic oil which is a great leap from good old ep 80.
knowing that gl5 spec is not good in a box that was only speced for gl4 and oils that advertized as gl4/gl5 are just as bad for a gl4 box it all seems a bit confused. auto data say its a gl4 spec??? fiat say gl5 fully synthetic.

 

[David C]

When I did mine, the Fiat dealer sold me Selenia, TUTELA ZC 75 Synth. (needed it in a rush as had the offer of the use of a garage to replace the wet driveshaft boot...)
Which at the time was a 75W90 GL5. That itself has now become 75W80 after also being a 75W85 for a while.

So, yes it is confusing, especially if the spec'd oil is no longer the same spec as when it was first spec'd...

Mine has been ok with the GL5.
Would I use GL4 next time... possibly.

The above is probably no help at all, but at least shows that the box didn't collapse in a heap with the use of GL5 synthetic...!

 

[rehtnap]

hi
yeh. i do know gl5 in a gl4 speced box can reduce syncro life a lot. it has to do with the antiwear deposit being double in gl5 and as it wears off it is so bonded to the syncro it pulls a microscopic layer of metal off.
i have some fully synthetic 75/90 gl4 im going to try in mine. i recon its half way between the first spec and the latest. it wouldnt surprise me if fiat did change the internal spec of the gearbox. when i come to power there will be one gear oil and one engine oil.

 

[Huwbishop]

It's an 899 so there isn't a lot of strain on the box anyway. I just use ep80 and balls to whether it likes it or not.

Not had any problems with wear, just internals committing suicide and leaks.
None of it down to oil, just bad luck with previously abused second hand boxes sitting about in scrap yards for too long.

 

[rehtnap]

i like your style. after all this gearbox isnt exactly a formula one slick shift. there is so much confused and part info out there,cut and paste has a lot to answerer for. what i have found out is some gl5 spec oils are ok with yellow metal and some are not it. its down to a corrosion test a lot of gl5 oils dont get as they are ment for hypoid boxes with no yellow metal parts. all way too techy.

 

[Huwbishop]

Gearbox technology in cars isn't a lot different than 30years ago, what swaps the cogs may have changed, but what is inside is essentially the same.

Truth is, if you change the oil in you're box to a good quality oil of the recommended grade, there is no reason why that should be the last you have to worry about it.
Let's face it, cars of this age are either going to be eaten by rust goblins, or some silly idiot is going to drive into it.

Save you're self a few quid and have another pint.

 

[rehtnap]

yes i have decided that if it was a low mileage box id use the fully synthetic stuff fiat recommend but as it has 90000 miles on it im going to go back to a mineral 80w oil and get the last out of the syncro`s. me thinks the synthetic and semi synthetic is now too slippery for them. im going for a gl5 spec as from what i read most of the modern oils are now safe with yellow metal.