Thought you guys might like to read this.
At the NEC Classic Car show here in the Uk back in 2012 I got talking to a man called Mike Smith who had worked at Leyland Tramsmissions for 28 years developing the LT77 & the later R380 boxes. He later emailed me with these comments:
<font color="blue">When I was at Landrover developing the LT77 and the R380 unit we assessed various oils to give good gear and bearing life and smooth synchro performance. Together with Texaco we came up with the MTF94 as the best all rounder. I do remember assessing an Elf transmission oil that was also very good, so perhaps if you have the time and are still striving for more improvements you could try Elf.
I do not recognise any of the oils you mention in your list, so I cannot help you there, but of course there are many many influences on synchro performance, ie inertia of the clutch plate, design of the synchromesh system, coefficient of friction of the components, and sometimes the spec of the oil was an immediate no no to work with the design, so we never tried it. Dont forget that an arduous rig test which really proved the longevity of all components was carried out before we would recommend an oil for production, so I am sure you will find some advantage using the Texaco product.
Yes we did try ATF oil and it was good, but we favoured it only because it was able to run at a much higher temperature,and still maintain its viscosity and qualities. It also gave less resistance to the components which as you can appreciate these days is very important to fuel consumption, etc, etc.
The gearbox oil especially the Texaco products were designed for lifetime running, but like yourself I would change my transmission oil before that.
Unfortunately I seem to have forgotten a lot of info , but I worked at Landrover on manual gearboxes and transfer gearboxes for 28 years and travelled the world testing and destroying transmissions which was a great job.</font id="blue">
I think the Texaco MTF94 is now out of production, but it was interesting to talk with someone who was so deeply involved in the development side at Leyland & Landrover.
I use Motul Gear 300 in my TR8 box, it's very good & was the recommendation of the late Ken Tomlinson who built the boxes for BL Motorsport. In my TR7 I have Castrol SMX which is also very good, in fact the Castrol is a little better from cold in reducing the baulkiness from 1st to 2nd.
Of course we are talking about what is available here in the UK so in the States other brands may be just as good & more easy to find.
Tony
<font size="1">1981 TR7 FHC Cavalry Blue
1980 TR7V8 DHC Jaguar Regency Red - sadly sold!
1977 TR8 FHC EFI Factory development car Inca Yellow</font id="size1">
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