LT77 gearbox oil

[stephencdavies]

Ok. i have no doubt this topic has come up time and time again, but i want an informed opinion from you guys.

i have an aged LT77 gearbox. it's a bit notchy, but not overly. i drained the gearbox oil out and refilled it with ATF a few months ago. my intention was that this was just a flush. the gearbox had been idle a long time. i've only done about 500 miles in it but it was only supposed to be a flush, so i'm now about to change it.

I've read that LR stopped recommending ATF in the LT77 gear box at some point and started to use MTF.

so what do you think, ATF or MTF

1/ what gearbox oil do you use. ATF or MTF. why this choice of oil.

2/ how often do you change your gearbox oil

3/ what brand do you use

thanks , steve

[Snagger]

I went from ATF Dextron III to MTF84 on my R380 and it was a big improvement. DIfflock also do an oil for it, but I can't remember anything other than that it was shockingly expensive!

[Mo Murphy]

ATF is still the recommendation for the LT77. MTF for the R380.

Mo

[miketomcat]

What mo said.

Mike

[GW8IZR]

1/ what gearbox oil do you use. ATF or MTF. why this choice of oil.

ATF, because its what is recommended by the manufacturer and Mr Ashcroft when I asked him :-) They both know more about it than me

2/ how often do you change your gearbox oil

Six months after the rebuild and from now on the recommended interval

3/ what brand do you use

To be honest whatever is on the shelf at the factor at a reasonable price.

HTH

[stephencdavies]

Thats that then. i'll stick with ATF. thanks everyone.

[Ex Member]

ATF is still the recommendation for the LT77. MTF for the R380.

Mo

They are more or less the same gearbox internally. Any MTF (there are many of them) will help prevent synchro contact and wear. It was never recommended for the LT77, because the fluid did not exist when they where making them.

[Ally V8]

MTF, improves shift quality - even my wife noticed it was better many years ago when I changed to it in her RRC TDI/LT77.

[stephencdavies]

HHHHmmmm the plot thickens.

[Ex Member]

Basically.... Most MTFs are thicker, making it harder to collapse the synchro film, causing synchro wear if the shift is forced. In order to allow rapid shifting, they use friction modifier that increase friction allowing the synchros to shift at an acceptable rate with the thicker fluid. The thicker fluid also provide better gear and bearing protection. There is really no downside.

[marktdi]

This is interesting . I have always used atf . My gear oil is due a change and I'm now thinking mtf might be an option

[reb78]

There is really no downside.

Well, it is more expensive and on my box (prior to

It's current issues - unrelated to oil) there was no difference between ATF or MTF. I figured stick with ATF as it's cheaper and change it more often.

[Diff]

In the past, I have tried both the Difflock evo oil and Land rover's MTF in my LT77, in both cases I switched back to ATF because the slight notchiness of the gear change was made worse.

I now use the ATF which is recommended by Ashcroft Transmissions on their website for LT77 gearboxes(Triple QX ATF Dextron III from Euro car parts). They should know what works. I am very happy with it. My gearbox has now done 188,000 miles on ATF and the notchiness is no worse than it was at 100,000 miles.

Regards, Diff.

[Ex Member]

They should know what works. I am very happy with it. My gearbox has now done 188,000 miles on ATF and the notchiness is no worse than it was at 100,000 miles.

Regards, Diff.

Actually... I've personally talked with Mr. Ashcroft on this subject. They suggest ATF because that was the latest recommendation from Land Rover. They do not want to get involved with recommending something else. It just leaves them open to people coming back to them with holding them responsible for failures based on their recommendation.

ATF will be fine as long as you know how to shift. The problem, as mentioned earlier, is that it is easier to cause synchro wear with it, if you try and rush a shift. Most people don't know how to shift. The MTF adds some safety factor and that is why Land Rover changed to recommending it midway through the R380 period.

[stephencdavies]

Some guy on anther Defender forum suggests mixing ATF and MTF. What hecks that about????

[Snagger]

With the R380 being a strengthened LT77 derivative, I'd use MTF94. The lubricating and protective qualities of ATF are not good. But any oil will give a bad gear change if it is rushed. The LT77 and R380 should be used with a brief "selection", or pause, in neutral. This is achieved when going up or dwon between 2nd and 3rd or 4th and 5th by the time taken to move the gear stick laterally to the next gate. It is the selections between 1st and 2nd or 3rd and 4th that get rushed, and the 2nd gear baulk ring wear is a known issue, easily solved by that very simple pause.