Which oil for LT77 gearbox

[martin_t]

Hi

Can anyone advise me on which oil to use in my SD1 LT77 gearbox please?

on a similar subject I am putting Valvoline 20/50 racing in the engine and Valvoline 80-90 GL-5 in the diff. Does that sound OK?

Thanks

Martin

[Sidecarbod]

Originally Posted by martin_t

Hi

Can anyone advise me on which oil to use in my SD1 LT77 gearbox please?

on a similar subject I am putting Valvoline 20/50 racing in the engine and Valvoline 80-90 GL-5 in the diff. Does that sound OK?

Thanks

Martin

Hi Martin,

I use Redline MTL (Not the 90 grade or heavy shock oil) in my LT77:-

Red Line Oil: Gear Lubricants


If you believe the gumph on the website its very good stuff.

The gearchange is slightly slow when the box is stone cold but is fine after a few miles. It is much better than the crap that Rover recomend.

The other oil that is suposed to be OK is Castrol SMX.

Vavoline VR1 20/50 is the right oil for motor.

Can't help with the diff...sorry!.

HTH,

Pete

[demus]

Was just about to ask the same question, can anyone also advise on the frequency of oil changes for the diff and gearbox? gearbox is LT77, not sure about the diff but is Jag lsd.

[craggle]

Standard or open diffs can be run with standard EP 80/90 gear oil.

Powerlock oil is special. It's essentially a standard EP80/90 gear oil but it has additives that prevent the clutch plates being damaged.

The Jag limited slip unit consists of clutch plates and spring washers that control the preload. Apparently using the wrong oil can cause the plates to swell and lock solid or fall apart and leave you with an open diff.

I use Morris XEP90 oil XEP 90 - Morris Lubricants - UK

Apparently Jag dealers will sell you a concentrate that you add to the diff before topping up with standard gear oil that does the same thing as the oil I used.

Craig.

[DELAGE]

A fully synthetic 72W/90 gear oil do not under any circumstances use TQF/ red auto fluid you will wreck every gear box you fit be it LT77 or R380 if used under load, IE track day work etc

[demus]

Craig,

When the plates lock solid, how solid does the diff go, would it be a nightmare to steer??

The diff on mine is pretty tight, if one side of the rear is jacked up and put down again the diff will stop the car from settling level untill I move it under power. The car drives well and steers ok so I'm guessing the diff is ok??

[Sidecarbod]

Originally Posted by DELAGE

A fully synthetic 72W/90 gear oil do not under any circumstances use TQF/ red auto fluid you will wreck every gear box you fit be it LT77 or R380 if used under load, IE track day work etc

Hi Leo,

Are you saying that the MTL stuff is no good for an LT77?

The tec PDF on the Redline website talks in detail about what the oil needs to do in a syncro box.

Regards,

Pete

[craggle]

Originally Posted by demus

Craig,

When the plates lock solid, how solid does the diff go, would it be a nightmare to steer??

The diff on mine is pretty tight, if one side of the rear is jacked up and put down again the diff will stop the car from settling level untill I move it under power. The car drives well and steers ok so I'm guessing the diff is ok??

I think what you are describing is related to the suspension.

If you measure the distance between the inside face of each wheel, then jack the wheels off the floor and measure again the measurement will have reduced. The wishbones on the jag Independent rear suspension move through an arc. If I jack my car up in the garage when it's parked on the carpet tiles, the tiles will move towards the centre of the car on the floor as the load is reduced. If I then lower the car back down it sits about 2-3" too high until it is pushed forwards or backwards.

If you can jack one wheel off the floor with the car in neutral and then turn that wheel with some resistance then the Limited slip diff is working. It should be fairly hard to turn but not to the point where you are blue in the face. If you can turn the wheel with no effort then you have an open diff or a non working limited slip one.

Craig.

[demus]

Thanks Craig,

Next time I jack the car up I'll try what you said. I think from memory it is quite hard to turn, but certainly didnt try to the extent of being blue faced..

Thanks again...

[DELAGE]

Originally Posted by Sidecarbod

Hi Leo,

Are you saying that the MTL stuff is no good for an LT77?

The tec PDF on the Redline website talks in detail about what the oil needs to do in a syncro box.

Regards,

Pete

Hi Pete yes exactly that, If my memory serves me correctly the older boxes LT77 fitted to TR7, SD1 and the like used to use EP80/90 gear oil, but Leyland in there wisdom due to complaints by women who could not get it in gear on a cold start recommended using auto/TQF type fluid the alleviate the problem. Perfectly okay for normal day to day work but not for heavy loading. I have recked three gearboxes (LT77) doing track days with this oil. I then woke up and D J Ellis when supplying me with a new R380 told me to use Vavoline fully synthetic 72W/90 I think or similar and nothing else.

Not had a problem since that time, but I have to say the R380 box in my opinion is a far better box which helps