Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Quantities

What does probably mean?
You know for a fact that it is perfectly acceptable to mix ATF and Syntrans, or you don’t know?

I am not being funny, but putting anything other than ATF into an LT77 gearbox seizes it up.

Agreed about the LT77. Yours is a R380. The Castrol option is OK for that. I would always ask the professionals, in your csse it looks like Lifes, anyway and maybe before asking on this forum.

Seizes it up ? Curious.... I've now done 191+k miles with Scruffymog's LT77 always using Castrol Syntrans with regular oil changes and it hasn't seized up yet. The only problem I've had was a worn input-shaft taper bearing (at 159k miles, causing the shaft to move slightly under load and 'box to get stuck in 4th) but apart from that, no problems at all.
Perhaps I've been lucky but I can't honestly see why Syntrans would cause a problem in the LT77 and not the R380...

Yeah, but wait until you've got a few miles on it.

I take your points. I based my opinion on quite a sizeable article in GoMog detailing the LT77 gearbox.
It explained that there is a small pump with a plastic impeller which is easily overwhelmed if the oil is too thick, with catastrophic consequences.
I am grateful for the information about Castrol Syntrans, which I am keen to install.

Incidentally, I replaced the diff oil today with MPM 75W-140 fully synthetic gear oil at £27 per litre.
Owners manual said 1 litre, GoMog said 1.3.
Actually probably 1.4.
Now if only the gearbox access hole was on the same side as the filler plug.

My '94 +8 has the LT77 gear box. From day one it had an intermittent fault of not being able to select first gear. While at the Factory having it's first service I mentioned this to the Service Manager who said "some of them do that". [a rare variation of "they all......"] If first gear was blocked I was advised to shift into second gear, then first. After some practice I mastered the technique and caused very few hold ups at traffic lights. 17 years later I retired and took over the routine maintenance. All the recommended fluids were no longer available! In 2016, for the gear box 'oil' change, I used Comma Automatic Transmission Fluid, AQF, Mineral, which has equivalent specs. About 2 liters from memory. Since then the gear changes have been perfect with no block on first gear.

Well, today I have completed the gearbox oil change to Castrol Syntrans.
A quick 20 mile test drive confirmed that it is quite a bit smoother than the ATF that was in before.
Just over 2 (maybe 2.2) litres of red ATF came out and 2.6 litres of Syntrans went in.
As the filler is on the right, I fabricated a length of hose pipe with a funnel attached fed down from the engine compartment and deftly pushed into the filler hole.
Then, the first two litres was easy, but I recruited my better half to pour the last half litre or so while I watched underneath.

That’s the last of the oil changes now. I am grateful for all your advice and comments. Although I was a mechanic in the army, that was a long time ago and I feel very much the novice now.
I still have an intermittent stall, which I feel is related to a battery drain, but I will know more when the auto electrician has done his thing with it next week.
At the moment I am quite pleased with myself and the car.
It is a journey and I am enjoying it.
Over and out.
Phil