Best gearbox oil for automated manual transmission

[oppilif]

Hi all!
I live in Italy and my gf has an old diesel Smart car with a getrag 6 speed manual automated transmission that calls for dexron 3 atf, since there are now on the market very thin manual transmission fluids with the same viscosity of dexron 3 I wonder if putting in one of those would be potentially better on syncro or bearing life rather than the atf, for example ravenol mtf 3 or liqui moly top tec 5300, I'd like to know your opinion on this, thank you

 

[Snagglefoot]

Dexron 3 has been superseded by Dexron 6, so that would be the starting point.

 

[Snagglefoot]

I recall that manually shifted “ automatic” transmission. The nature of automatic transmissions involves the use of clutches with fibrous material. I don't think manual transmission fluid takes that into account, but you pose an interesting question. I believe the “manual” part of it, is that it doesn’t use electric solenoids to activate the shifts, but the clutches still exist.

 

[Bailes1992]

I kind-of had the same idea as you.

Our Defender has a Land Rover R380 gearbox that was originally specified for Dexron II. Later on in the R380's life Land Rover came up with an MTF called "MTF-94" which was basically a 75w80 MTF with a few extra requirements and back spec'd all the R380's.

I've tried ATF, genuine MTF94 and a few generic 75w80 MTF's. But on the last service I had Castrol Syntrans 75w FE on the shelf which is an MTF that's around the same viscosity at Dexron II. Threw it in and it's the smoothest I've never known it in the 10 years or so we've had it. Still feels awful being an old Land Rover, but less awful than the other fluids.

My only concern with the automated manual, is if the fluid is used for any actuation/hydraulic purposes.

 

[oppilif]

Actually is not used for any hydraulic in my application hence why i think is potentially ideal to use a modern low viscosity mtf, but my intrest would be to understand if something like castrol 75w fe or one of the ones i cited before would be more useful for bearing, gears and syncro life because of the different additive package than dexron 3 or 6, who knows

 

[atikovi]

I recall that manually shifted “ automatic” transmission. The nature of automatic transmissions involves the use of clutches with fibrous material. I don't think manual transmission fluid takes that into account, but you pose an interesting question. I believe the “manual” part of it, is that it doesn’t use electric solenoids to activate the shifts, but the clutches still exist.

No, manual automated transmission is just what it says. A manual transmission with automated controls. I'll have to check what I used on my Smart diesel, but if it says Dexron 3, just use Dexron 6.

 

[Falcon_LS]

If it calls for Dexron III, I would use TES-295 fluid. If you have access to Liqui Moly products, you could use their Top Tec ATF 1200 with the orange label.

 

[Jetronic]

I recall that manually shifted “ automatic” transmission. The nature of automatic transmissions involves the use of clutches with fibrous material. I don't think manual transmission fluid takes that into account, but you pose an interesting question. I believe the “manual” part of it, is that it doesn’t use electric solenoids to activate the shifts, but the clutches still exist.

They operate like a manual transmission, except the clutch is solenoid controlled, as is the actual shifting. It's a dry clutch.